From e710f654015d2d35d8a8df07ef54ddbc442cbc9d Mon Sep 17 00:00:00 2001
From: Bin Lu <bin.lu@arm.com>
Date: Tue, 26 Nov 2019 15:53:26 +0800
Subject: Prepare the vcpu environment for a container application

    Mainly 2 jobs were finished in this patch:
    1, context switching for a container application:
        a, R0-R30 b, pc\pstate\sp_el0 c, pagetable_el0 for container application
       This job can help us to pass the following test cases:
       "TestApplicationSyscall", "TestApplicationFault"
    2, checking pagetable_el0 is empty
       This job can help us to pass the following test case: "TestInvalidate"

Signed-off-by: Bin Lu <bin.lu@arm.com>
---
 pkg/sentry/platform/ring0/entry_arm64.s | 67 +++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)

diff --git a/pkg/sentry/platform/ring0/entry_arm64.s b/pkg/sentry/platform/ring0/entry_arm64.s
index 29c475882..674c569e1 100644
--- a/pkg/sentry/platform/ring0/entry_arm64.s
+++ b/pkg/sentry/platform/ring0/entry_arm64.s
@@ -337,6 +337,73 @@ TEXT ·Current(SB),NOSPLIT,$0-8
 #define STACK_FRAME_SIZE 16
 
 TEXT ·kernelExitToEl0(SB),NOSPLIT,$0
+	// Step1, save sentry context into memory.
+	REGISTERS_SAVE(RSV_REG, CPU_REGISTERS)
+	MOVD RSV_REG_APP, CPU_REGISTERS+PTRACE_R9(RSV_REG)
+
+	WORD $0xd5384003    //    MRS SPSR_EL1, R3
+	MOVD R3, CPU_REGISTERS+PTRACE_PSTATE(RSV_REG)
+	MOVD R30, CPU_REGISTERS+PTRACE_PC(RSV_REG)
+	MOVD RSP, R3
+	MOVD R3, CPU_REGISTERS+PTRACE_SP(RSV_REG)
+
+	MOVD CPU_REGISTERS+PTRACE_R3(RSV_REG), R3
+
+	// Step2, save SP_EL1, PSTATE into kernel temporary stack.
+	// switch to temporary stack.
+	LOAD_KERNEL_STACK(RSV_REG)
+	WORD $0xd538d092    //MRS   TPIDR_EL1, R18
+
+	SUB $STACK_FRAME_SIZE, RSP, RSP
+	MOVD CPU_REGISTERS+PTRACE_SP(RSV_REG), R11
+	MOVD CPU_REGISTERS+PTRACE_PSTATE(RSV_REG), R12
+	STP (R11, R12), 16*0(RSP)
+
+	MOVD CPU_REGISTERS+PTRACE_R11(RSV_REG), R11
+	MOVD CPU_REGISTERS+PTRACE_R12(RSV_REG), R12
+
+	// Step3, test user pagetable.
+	// If user pagetable is empty, trapped in el1_ia.
+	WORD $0xd538d092    //MRS   TPIDR_EL1, R18
+	SWITCH_TO_APP_PAGETABLE(RSV_REG)
+	WORD $0xd538d092    //MRS   TPIDR_EL1, R18
+	SWITCH_TO_KVM_PAGETABLE(RSV_REG)
+	WORD $0xd538d092    //MRS   TPIDR_EL1, R18
+
+	// If pagetable is not empty, recovery kernel temporary stack.
+	ADD $STACK_FRAME_SIZE, RSP, RSP
+
+	// Step4, load app context pointer.
+	MOVD CPU_APP_ADDR(RSV_REG), RSV_REG_APP
+
+	// Step5, prepare the environment for container application.
+	// set sp_el0.
+	MOVD PTRACE_SP(RSV_REG_APP), R1
+	WORD $0xd5184101        //MSR R1, SP_EL0
+	// set pc.
+	MOVD PTRACE_PC(RSV_REG_APP), R1
+	MSR R1, ELR_EL1
+	// set pstate.
+	MOVD PTRACE_PSTATE(RSV_REG_APP), R1
+	WORD $0xd5184001  //MSR R1, SPSR_EL1
+
+	// RSV_REG & RSV_REG_APP will be loaded at the end.
+	REGISTERS_LOAD(RSV_REG_APP, 0)
+
+	// switch to user pagetable.
+	MOVD PTRACE_R18(RSV_REG_APP), RSV_REG
+	MOVD PTRACE_R9(RSV_REG_APP), RSV_REG_APP
+
+	SUB $STACK_FRAME_SIZE, RSP, RSP
+	STP (RSV_REG, RSV_REG_APP), 16*0(RSP)
+
+	WORD $0xd538d092    //MRS   TPIDR_EL1, R18
+
+	SWITCH_TO_APP_PAGETABLE(RSV_REG)
+
+	LDP 16*0(RSP), (RSV_REG, RSV_REG_APP)
+	ADD $STACK_FRAME_SIZE, RSP, RSP
+
 	ERET()
 
 TEXT ·kernelExitToEl1(SB),NOSPLIT,$0
-- 
cgit v1.2.3


From cb533f18cbb93e3f236ba191d1693e93716313b5 Mon Sep 17 00:00:00 2001
From: Haibo Xu <haibo.xu@arm.com>
Date: Mon, 18 Nov 2019 09:34:02 +0000
Subject: Enable pkg/sentry/strace support on arm64.

Signed-off-by: Haibo Xu <haibo.xu@arm.com>
Change-Id: I006a1845b6aab2c2fdb9d80fffc1868a6a132ecd
---
 pkg/sentry/strace/BUILD            |   3 +-
 pkg/sentry/strace/linux64.go       | 367 -----------------------------------
 pkg/sentry/strace/linux64_amd64.go | 382 +++++++++++++++++++++++++++++++++++++
 pkg/sentry/strace/linux64_arm64.go | 323 +++++++++++++++++++++++++++++++
 pkg/sentry/strace/syscalls.go      |   9 +-
 5 files changed, 708 insertions(+), 376 deletions(-)
 delete mode 100644 pkg/sentry/strace/linux64.go
 create mode 100644 pkg/sentry/strace/linux64_amd64.go
 create mode 100644 pkg/sentry/strace/linux64_arm64.go

diff --git a/pkg/sentry/strace/BUILD b/pkg/sentry/strace/BUILD
index d46421199..aa1ac720c 100644
--- a/pkg/sentry/strace/BUILD
+++ b/pkg/sentry/strace/BUILD
@@ -10,7 +10,8 @@ go_library(
         "capability.go",
         "clone.go",
         "futex.go",
-        "linux64.go",
+        "linux64_amd64.go",
+        "linux64_arm64.go",
         "open.go",
         "poll.go",
         "ptrace.go",
diff --git a/pkg/sentry/strace/linux64.go b/pkg/sentry/strace/linux64.go
deleted file mode 100644
index e603f858f..000000000
--- a/pkg/sentry/strace/linux64.go
+++ /dev/null
@@ -1,367 +0,0 @@
-// Copyright 2018 The gVisor Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package strace
-
-// linuxAMD64 provides a mapping of the Linux amd64 syscalls and their argument
-// types for display / formatting.
-var linuxAMD64 = SyscallMap{
-	0:   makeSyscallInfo("read", FD, ReadBuffer, Hex),
-	1:   makeSyscallInfo("write", FD, WriteBuffer, Hex),
-	2:   makeSyscallInfo("open", Path, OpenFlags, Mode),
-	3:   makeSyscallInfo("close", FD),
-	4:   makeSyscallInfo("stat", Path, Stat),
-	5:   makeSyscallInfo("fstat", FD, Stat),
-	6:   makeSyscallInfo("lstat", Path, Stat),
-	7:   makeSyscallInfo("poll", PollFDs, Hex, Hex),
-	8:   makeSyscallInfo("lseek", Hex, Hex, Hex),
-	9:   makeSyscallInfo("mmap", Hex, Hex, Hex, Hex, FD, Hex),
-	10:  makeSyscallInfo("mprotect", Hex, Hex, Hex),
-	11:  makeSyscallInfo("munmap", Hex, Hex),
-	12:  makeSyscallInfo("brk", Hex),
-	13:  makeSyscallInfo("rt_sigaction", Signal, SigAction, PostSigAction),
-	14:  makeSyscallInfo("rt_sigprocmask", SignalMaskAction, SigSet, PostSigSet, Hex),
-	15:  makeSyscallInfo("rt_sigreturn"),
-	16:  makeSyscallInfo("ioctl", FD, Hex, Hex),
-	17:  makeSyscallInfo("pread64", FD, ReadBuffer, Hex, Hex),
-	18:  makeSyscallInfo("pwrite64", FD, WriteBuffer, Hex, Hex),
-	19:  makeSyscallInfo("readv", FD, ReadIOVec, Hex),
-	20:  makeSyscallInfo("writev", FD, WriteIOVec, Hex),
-	21:  makeSyscallInfo("access", Path, Oct),
-	22:  makeSyscallInfo("pipe", PipeFDs),
-	23:  makeSyscallInfo("select", Hex, SelectFDSet, SelectFDSet, SelectFDSet, Timeval),
-	24:  makeSyscallInfo("sched_yield"),
-	25:  makeSyscallInfo("mremap", Hex, Hex, Hex, Hex, Hex),
-	26:  makeSyscallInfo("msync", Hex, Hex, Hex),
-	27:  makeSyscallInfo("mincore", Hex, Hex, Hex),
-	28:  makeSyscallInfo("madvise", Hex, Hex, Hex),
-	29:  makeSyscallInfo("shmget", Hex, Hex, Hex),
-	30:  makeSyscallInfo("shmat", Hex, Hex, Hex),
-	31:  makeSyscallInfo("shmctl", Hex, Hex, Hex),
-	32:  makeSyscallInfo("dup", FD),
-	33:  makeSyscallInfo("dup2", FD, FD),
-	34:  makeSyscallInfo("pause"),
-	35:  makeSyscallInfo("nanosleep", Timespec, PostTimespec),
-	36:  makeSyscallInfo("getitimer", ItimerType, PostItimerVal),
-	37:  makeSyscallInfo("alarm", Hex),
-	38:  makeSyscallInfo("setitimer", ItimerType, ItimerVal, PostItimerVal),
-	39:  makeSyscallInfo("getpid"),
-	40:  makeSyscallInfo("sendfile", FD, FD, Hex, Hex),
-	41:  makeSyscallInfo("socket", SockFamily, SockType, SockProtocol),
-	42:  makeSyscallInfo("connect", FD, SockAddr, Hex),
-	43:  makeSyscallInfo("accept", FD, PostSockAddr, SockLen),
-	44:  makeSyscallInfo("sendto", FD, Hex, Hex, Hex, SockAddr, Hex),
-	45:  makeSyscallInfo("recvfrom", FD, Hex, Hex, Hex, PostSockAddr, SockLen),
-	46:  makeSyscallInfo("sendmsg", FD, SendMsgHdr, Hex),
-	47:  makeSyscallInfo("recvmsg", FD, RecvMsgHdr, Hex),
-	48:  makeSyscallInfo("shutdown", FD, Hex),
-	49:  makeSyscallInfo("bind", FD, SockAddr, Hex),
-	50:  makeSyscallInfo("listen", FD, Hex),
-	51:  makeSyscallInfo("getsockname", FD, PostSockAddr, SockLen),
-	52:  makeSyscallInfo("getpeername", FD, PostSockAddr, SockLen),
-	53:  makeSyscallInfo("socketpair", SockFamily, SockType, SockProtocol, Hex),
-	54:  makeSyscallInfo("setsockopt", FD, Hex, Hex, Hex, Hex),
-	55:  makeSyscallInfo("getsockopt", FD, Hex, Hex, Hex, Hex),
-	56:  makeSyscallInfo("clone", CloneFlags, Hex, Hex, Hex, Hex),
-	57:  makeSyscallInfo("fork"),
-	58:  makeSyscallInfo("vfork"),
-	59:  makeSyscallInfo("execve", Path, ExecveStringVector, ExecveStringVector),
-	60:  makeSyscallInfo("exit", Hex),
-	61:  makeSyscallInfo("wait4", Hex, Hex, Hex, Rusage),
-	62:  makeSyscallInfo("kill", Hex, Signal),
-	63:  makeSyscallInfo("uname", Uname),
-	64:  makeSyscallInfo("semget", Hex, Hex, Hex),
-	65:  makeSyscallInfo("semop", Hex, Hex, Hex),
-	66:  makeSyscallInfo("semctl", Hex, Hex, Hex, Hex),
-	67:  makeSyscallInfo("shmdt", Hex),
-	68:  makeSyscallInfo("msgget", Hex, Hex),
-	69:  makeSyscallInfo("msgsnd", Hex, Hex, Hex, Hex),
-	70:  makeSyscallInfo("msgrcv", Hex, Hex, Hex, Hex, Hex),
-	71:  makeSyscallInfo("msgctl", Hex, Hex, Hex),
-	72:  makeSyscallInfo("fcntl", FD, Hex, Hex),
-	73:  makeSyscallInfo("flock", FD, Hex),
-	74:  makeSyscallInfo("fsync", FD),
-	75:  makeSyscallInfo("fdatasync", FD),
-	76:  makeSyscallInfo("truncate", Path, Hex),
-	77:  makeSyscallInfo("ftruncate", FD, Hex),
-	78:  makeSyscallInfo("getdents", FD, Hex, Hex),
-	79:  makeSyscallInfo("getcwd", PostPath, Hex),
-	80:  makeSyscallInfo("chdir", Path),
-	81:  makeSyscallInfo("fchdir", FD),
-	82:  makeSyscallInfo("rename", Path, Path),
-	83:  makeSyscallInfo("mkdir", Path, Oct),
-	84:  makeSyscallInfo("rmdir", Path),
-	85:  makeSyscallInfo("creat", Path, Oct),
-	86:  makeSyscallInfo("link", Path, Path),
-	87:  makeSyscallInfo("unlink", Path),
-	88:  makeSyscallInfo("symlink", Path, Path),
-	89:  makeSyscallInfo("readlink", Path, ReadBuffer, Hex),
-	90:  makeSyscallInfo("chmod", Path, Mode),
-	91:  makeSyscallInfo("fchmod", FD, Mode),
-	92:  makeSyscallInfo("chown", Path, Hex, Hex),
-	93:  makeSyscallInfo("fchown", FD, Hex, Hex),
-	94:  makeSyscallInfo("lchown", Path, Hex, Hex),
-	95:  makeSyscallInfo("umask", Hex),
-	96:  makeSyscallInfo("gettimeofday", Timeval, Hex),
-	97:  makeSyscallInfo("getrlimit", Hex, Hex),
-	98:  makeSyscallInfo("getrusage", Hex, Rusage),
-	99:  makeSyscallInfo("sysinfo", Hex),
-	100: makeSyscallInfo("times", Hex),
-	101: makeSyscallInfo("ptrace", PtraceRequest, Hex, Hex, Hex),
-	102: makeSyscallInfo("getuid"),
-	103: makeSyscallInfo("syslog", Hex, Hex, Hex),
-	104: makeSyscallInfo("getgid"),
-	105: makeSyscallInfo("setuid", Hex),
-	106: makeSyscallInfo("setgid", Hex),
-	107: makeSyscallInfo("geteuid"),
-	108: makeSyscallInfo("getegid"),
-	109: makeSyscallInfo("setpgid", Hex, Hex),
-	110: makeSyscallInfo("getppid"),
-	111: makeSyscallInfo("getpgrp"),
-	112: makeSyscallInfo("setsid"),
-	113: makeSyscallInfo("setreuid", Hex, Hex),
-	114: makeSyscallInfo("setregid", Hex, Hex),
-	115: makeSyscallInfo("getgroups", Hex, Hex),
-	116: makeSyscallInfo("setgroups", Hex, Hex),
-	117: makeSyscallInfo("setresuid", Hex, Hex, Hex),
-	118: makeSyscallInfo("getresuid", Hex, Hex, Hex),
-	119: makeSyscallInfo("setresgid", Hex, Hex, Hex),
-	120: makeSyscallInfo("getresgid", Hex, Hex, Hex),
-	121: makeSyscallInfo("getpgid", Hex),
-	122: makeSyscallInfo("setfsuid", Hex),
-	123: makeSyscallInfo("setfsgid", Hex),
-	124: makeSyscallInfo("getsid", Hex),
-	125: makeSyscallInfo("capget", CapHeader, PostCapData),
-	126: makeSyscallInfo("capset", CapHeader, CapData),
-	127: makeSyscallInfo("rt_sigpending", Hex),
-	128: makeSyscallInfo("rt_sigtimedwait", SigSet, Hex, Timespec, Hex),
-	129: makeSyscallInfo("rt_sigqueueinfo", Hex, Signal, Hex),
-	130: makeSyscallInfo("rt_sigsuspend", Hex),
-	131: makeSyscallInfo("sigaltstack", Hex, Hex),
-	132: makeSyscallInfo("utime", Path, Utimbuf),
-	133: makeSyscallInfo("mknod", Path, Mode, Hex),
-	134: makeSyscallInfo("uselib", Hex),
-	135: makeSyscallInfo("personality", Hex),
-	136: makeSyscallInfo("ustat", Hex, Hex),
-	137: makeSyscallInfo("statfs", Path, Hex),
-	138: makeSyscallInfo("fstatfs", FD, Hex),
-	139: makeSyscallInfo("sysfs", Hex, Hex, Hex),
-	140: makeSyscallInfo("getpriority", Hex, Hex),
-	141: makeSyscallInfo("setpriority", Hex, Hex, Hex),
-	142: makeSyscallInfo("sched_setparam", Hex, Hex),
-	143: makeSyscallInfo("sched_getparam", Hex, Hex),
-	144: makeSyscallInfo("sched_setscheduler", Hex, Hex, Hex),
-	145: makeSyscallInfo("sched_getscheduler", Hex),
-	146: makeSyscallInfo("sched_get_priority_max", Hex),
-	147: makeSyscallInfo("sched_get_priority_min", Hex),
-	148: makeSyscallInfo("sched_rr_get_interval", Hex, Hex),
-	149: makeSyscallInfo("mlock", Hex, Hex),
-	150: makeSyscallInfo("munlock", Hex, Hex),
-	151: makeSyscallInfo("mlockall", Hex),
-	152: makeSyscallInfo("munlockall"),
-	153: makeSyscallInfo("vhangup"),
-	154: makeSyscallInfo("modify_ldt", Hex, Hex, Hex),
-	155: makeSyscallInfo("pivot_root", Path, Path),
-	156: makeSyscallInfo("_sysctl", Hex),
-	157: makeSyscallInfo("prctl", Hex, Hex, Hex, Hex, Hex),
-	158: makeSyscallInfo("arch_prctl", Hex, Hex),
-	159: makeSyscallInfo("adjtimex", Hex),
-	160: makeSyscallInfo("setrlimit", Hex, Hex),
-	161: makeSyscallInfo("chroot", Path),
-	162: makeSyscallInfo("sync"),
-	163: makeSyscallInfo("acct", Hex),
-	164: makeSyscallInfo("settimeofday", Timeval, Hex),
-	165: makeSyscallInfo("mount", Path, Path, Path, Hex, Path),
-	166: makeSyscallInfo("umount2", Path, Hex),
-	167: makeSyscallInfo("swapon", Hex, Hex),
-	168: makeSyscallInfo("swapoff", Hex),
-	169: makeSyscallInfo("reboot", Hex, Hex, Hex, Hex),
-	170: makeSyscallInfo("sethostname", Hex, Hex),
-	171: makeSyscallInfo("setdomainname", Hex, Hex),
-	172: makeSyscallInfo("iopl", Hex),
-	173: makeSyscallInfo("ioperm", Hex, Hex, Hex),
-	174: makeSyscallInfo("create_module", Path, Hex),
-	175: makeSyscallInfo("init_module", Hex, Hex, Hex),
-	176: makeSyscallInfo("delete_module", Hex, Hex),
-	177: makeSyscallInfo("get_kernel_syms", Hex),
-	// 178: query_module (only present in Linux < 2.6)
-	179: makeSyscallInfo("quotactl", Hex, Hex, Hex, Hex),
-	180: makeSyscallInfo("nfsservctl", Hex, Hex, Hex),
-	// 181: getpmsg (not implemented in the Linux kernel)
-	// 182: putpmsg (not implemented in the Linux kernel)
-	// 183: afs_syscall (not implemented in the Linux kernel)
-	// 184: tuxcall (not implemented in the Linux kernel)
-	// 185: security (not implemented in the Linux kernel)
-	186: makeSyscallInfo("gettid"),
-	187: makeSyscallInfo("readahead", Hex, Hex, Hex),
-	188: makeSyscallInfo("setxattr", Path, Path, Hex, Hex, Hex),
-	189: makeSyscallInfo("lsetxattr", Path, Path, Hex, Hex, Hex),
-	190: makeSyscallInfo("fsetxattr", FD, Path, Hex, Hex, Hex),
-	191: makeSyscallInfo("getxattr", Path, Path, Hex, Hex),
-	192: makeSyscallInfo("lgetxattr", Path, Path, Hex, Hex),
-	193: makeSyscallInfo("fgetxattr", FD, Path, Hex, Hex),
-	194: makeSyscallInfo("listxattr", Path, Path, Hex),
-	195: makeSyscallInfo("llistxattr", Path, Path, Hex),
-	196: makeSyscallInfo("flistxattr", FD, Path, Hex),
-	197: makeSyscallInfo("removexattr", Path, Path),
-	198: makeSyscallInfo("lremovexattr", Path, Path),
-	199: makeSyscallInfo("fremovexattr", FD, Path),
-	200: makeSyscallInfo("tkill", Hex, Signal),
-	201: makeSyscallInfo("time", Hex),
-	202: makeSyscallInfo("futex", Hex, FutexOp, Hex, Timespec, Hex, Hex),
-	203: makeSyscallInfo("sched_setaffinity", Hex, Hex, Hex),
-	204: makeSyscallInfo("sched_getaffinity", Hex, Hex, Hex),
-	205: makeSyscallInfo("set_thread_area", Hex),
-	206: makeSyscallInfo("io_setup", Hex, Hex),
-	207: makeSyscallInfo("io_destroy", Hex),
-	208: makeSyscallInfo("io_getevents", Hex, Hex, Hex, Hex, Timespec),
-	209: makeSyscallInfo("io_submit", Hex, Hex, Hex),
-	210: makeSyscallInfo("io_cancel", Hex, Hex, Hex),
-	211: makeSyscallInfo("get_thread_area", Hex),
-	212: makeSyscallInfo("lookup_dcookie", Hex, Hex, Hex),
-	213: makeSyscallInfo("epoll_create", Hex),
-	// 214: epoll_ctl_old (not implemented in the Linux kernel)
-	// 215: epoll_wait_old (not implemented in the Linux kernel)
-	216: makeSyscallInfo("remap_file_pages", Hex, Hex, Hex, Hex, Hex),
-	217: makeSyscallInfo("getdents64", FD, Hex, Hex),
-	218: makeSyscallInfo("set_tid_address", Hex),
-	219: makeSyscallInfo("restart_syscall"),
-	220: makeSyscallInfo("semtimedop", Hex, Hex, Hex, Hex),
-	221: makeSyscallInfo("fadvise64", FD, Hex, Hex, Hex),
-	222: makeSyscallInfo("timer_create", Hex, Hex, Hex),
-	223: makeSyscallInfo("timer_settime", Hex, Hex, ItimerSpec, PostItimerSpec),
-	224: makeSyscallInfo("timer_gettime", Hex, PostItimerSpec),
-	225: makeSyscallInfo("timer_getoverrun", Hex),
-	226: makeSyscallInfo("timer_delete", Hex),
-	227: makeSyscallInfo("clock_settime", Hex, Timespec),
-	228: makeSyscallInfo("clock_gettime", Hex, PostTimespec),
-	229: makeSyscallInfo("clock_getres", Hex, PostTimespec),
-	230: makeSyscallInfo("clock_nanosleep", Hex, Hex, Timespec, PostTimespec),
-	231: makeSyscallInfo("exit_group", Hex),
-	232: makeSyscallInfo("epoll_wait", Hex, Hex, Hex, Hex),
-	233: makeSyscallInfo("epoll_ctl", Hex, Hex, FD, Hex),
-	234: makeSyscallInfo("tgkill", Hex, Hex, Signal),
-	235: makeSyscallInfo("utimes", Path, Timeval),
-	// 236: vserver (not implemented in the Linux kernel)
-	237: makeSyscallInfo("mbind", Hex, Hex, Hex, Hex, Hex, Hex),
-	238: makeSyscallInfo("set_mempolicy", Hex, Hex, Hex),
-	239: makeSyscallInfo("get_mempolicy", Hex, Hex, Hex, Hex, Hex),
-	240: makeSyscallInfo("mq_open", Hex, Hex, Hex, Hex),
-	241: makeSyscallInfo("mq_unlink", Hex),
-	242: makeSyscallInfo("mq_timedsend", Hex, Hex, Hex, Hex, Hex),
-	243: makeSyscallInfo("mq_timedreceive", Hex, Hex, Hex, Hex, Hex),
-	244: makeSyscallInfo("mq_notify", Hex, Hex),
-	245: makeSyscallInfo("mq_getsetattr", Hex, Hex, Hex),
-	246: makeSyscallInfo("kexec_load", Hex, Hex, Hex, Hex),
-	247: makeSyscallInfo("waitid", Hex, Hex, Hex, Hex, Rusage),
-	248: makeSyscallInfo("add_key", Hex, Hex, Hex, Hex, Hex),
-	249: makeSyscallInfo("request_key", Hex, Hex, Hex, Hex),
-	250: makeSyscallInfo("keyctl", Hex, Hex, Hex, Hex, Hex),
-	251: makeSyscallInfo("ioprio_set", Hex, Hex, Hex),
-	252: makeSyscallInfo("ioprio_get", Hex, Hex),
-	253: makeSyscallInfo("inotify_init"),
-	254: makeSyscallInfo("inotify_add_watch", Hex, Path, Hex),
-	255: makeSyscallInfo("inotify_rm_watch", Hex, Hex),
-	256: makeSyscallInfo("migrate_pages", Hex, Hex, Hex, Hex),
-	257: makeSyscallInfo("openat", FD, Path, OpenFlags, Mode),
-	258: makeSyscallInfo("mkdirat", FD, Path, Hex),
-	259: makeSyscallInfo("mknodat", FD, Path, Mode, Hex),
-	260: makeSyscallInfo("fchownat", FD, Path, Hex, Hex, Hex),
-	261: makeSyscallInfo("futimesat", FD, Path, Hex),
-	262: makeSyscallInfo("newfstatat", FD, Path, Stat, Hex),
-	263: makeSyscallInfo("unlinkat", FD, Path, Hex),
-	264: makeSyscallInfo("renameat", FD, Path, Hex, Path),
-	265: makeSyscallInfo("linkat", FD, Path, Hex, Path, Hex),
-	266: makeSyscallInfo("symlinkat", Path, Hex, Path),
-	267: makeSyscallInfo("readlinkat", FD, Path, ReadBuffer, Hex),
-	268: makeSyscallInfo("fchmodat", FD, Path, Mode),
-	269: makeSyscallInfo("faccessat", FD, Path, Oct, Hex),
-	270: makeSyscallInfo("pselect6", Hex, SelectFDSet, SelectFDSet, SelectFDSet, Timespec, SigSet),
-	271: makeSyscallInfo("ppoll", PollFDs, Hex, Timespec, SigSet, Hex),
-	272: makeSyscallInfo("unshare", CloneFlags),
-	273: makeSyscallInfo("set_robust_list", Hex, Hex),
-	274: makeSyscallInfo("get_robust_list", Hex, Hex, Hex),
-	275: makeSyscallInfo("splice", FD, Hex, FD, Hex, Hex, Hex),
-	276: makeSyscallInfo("tee", FD, FD, Hex, Hex),
-	277: makeSyscallInfo("sync_file_range", FD, Hex, Hex, Hex),
-	278: makeSyscallInfo("vmsplice", FD, Hex, Hex, Hex),
-	279: makeSyscallInfo("move_pages", Hex, Hex, Hex, Hex, Hex, Hex),
-	280: makeSyscallInfo("utimensat", FD, Path, UTimeTimespec, Hex),
-	281: makeSyscallInfo("epoll_pwait", Hex, Hex, Hex, Hex, SigSet, Hex),
-	282: makeSyscallInfo("signalfd", Hex, Hex, Hex),
-	283: makeSyscallInfo("timerfd_create", Hex, Hex),
-	284: makeSyscallInfo("eventfd", Hex),
-	285: makeSyscallInfo("fallocate", FD, Hex, Hex, Hex),
-	286: makeSyscallInfo("timerfd_settime", FD, Hex, ItimerSpec, PostItimerSpec),
-	287: makeSyscallInfo("timerfd_gettime", FD, PostItimerSpec),
-	288: makeSyscallInfo("accept4", FD, PostSockAddr, SockLen, SockFlags),
-	289: makeSyscallInfo("signalfd4", Hex, Hex, Hex, Hex),
-	290: makeSyscallInfo("eventfd2", Hex, Hex),
-	291: makeSyscallInfo("epoll_create1", Hex),
-	292: makeSyscallInfo("dup3", FD, FD, Hex),
-	293: makeSyscallInfo("pipe2", PipeFDs, Hex),
-	294: makeSyscallInfo("inotify_init1", Hex),
-	295: makeSyscallInfo("preadv", FD, ReadIOVec, Hex, Hex),
-	296: makeSyscallInfo("pwritev", FD, WriteIOVec, Hex, Hex),
-	297: makeSyscallInfo("rt_tgsigqueueinfo", Hex, Hex, Signal, Hex),
-	298: makeSyscallInfo("perf_event_open", Hex, Hex, Hex, Hex, Hex),
-	299: makeSyscallInfo("recvmmsg", FD, Hex, Hex, Hex, Hex),
-	300: makeSyscallInfo("fanotify_init", Hex, Hex),
-	301: makeSyscallInfo("fanotify_mark", Hex, Hex, Hex, Hex, Hex),
-	302: makeSyscallInfo("prlimit64", Hex, Hex, Hex, Hex),
-	303: makeSyscallInfo("name_to_handle_at", FD, Hex, Hex, Hex, Hex),
-	304: makeSyscallInfo("open_by_handle_at", FD, Hex, Hex),
-	305: makeSyscallInfo("clock_adjtime", Hex, Hex),
-	306: makeSyscallInfo("syncfs", FD),
-	307: makeSyscallInfo("sendmmsg", FD, Hex, Hex, Hex),
-	308: makeSyscallInfo("setns", FD, Hex),
-	309: makeSyscallInfo("getcpu", Hex, Hex, Hex),
-	310: makeSyscallInfo("process_vm_readv", Hex, ReadIOVec, Hex, IOVec, Hex, Hex),
-	311: makeSyscallInfo("process_vm_writev", Hex, IOVec, Hex, WriteIOVec, Hex, Hex),
-	312: makeSyscallInfo("kcmp", Hex, Hex, Hex, Hex, Hex),
-	313: makeSyscallInfo("finit_module", Hex, Hex, Hex),
-	314: makeSyscallInfo("sched_setattr", Hex, Hex, Hex),
-	315: makeSyscallInfo("sched_getattr", Hex, Hex, Hex),
-	316: makeSyscallInfo("renameat2", FD, Path, Hex, Path, Hex),
-	317: makeSyscallInfo("seccomp", Hex, Hex, Hex),
-	318: makeSyscallInfo("getrandom", Hex, Hex, Hex),
-	319: makeSyscallInfo("memfd_create", Path, Hex), // Not quite a path, but close.
-	320: makeSyscallInfo("kexec_file_load", FD, FD, Hex, Hex, Hex),
-	321: makeSyscallInfo("bpf", Hex, Hex, Hex),
-	322: makeSyscallInfo("execveat", FD, Path, ExecveStringVector, ExecveStringVector, Hex),
-	323: makeSyscallInfo("userfaultfd", Hex),
-	324: makeSyscallInfo("membarrier", Hex, Hex),
-	325: makeSyscallInfo("mlock2", Hex, Hex, Hex),
-	326: makeSyscallInfo("copy_file_range", FD, Hex, FD, Hex, Hex, Hex),
-	327: makeSyscallInfo("preadv2", FD, ReadIOVec, Hex, Hex, Hex),
-	328: makeSyscallInfo("pwritev2", FD, WriteIOVec, Hex, Hex, Hex),
-	329: makeSyscallInfo("pkey_mprotect", Hex, Hex, Hex, Hex),
-	330: makeSyscallInfo("pkey_alloc", Hex, Hex),
-	331: makeSyscallInfo("pkey_free", Hex),
-	332: makeSyscallInfo("statx", FD, Path, Hex, Hex, Hex),
-	333: makeSyscallInfo("io_pgetevents", Hex, Hex, Hex, Hex, Timespec, SigSet),
-	334: makeSyscallInfo("rseq", Hex, Hex, Hex, Hex),
-	424: makeSyscallInfo("pidfd_send_signal", FD, Signal, Hex, Hex),
-	425: makeSyscallInfo("io_uring_setup", Hex, Hex),
-	426: makeSyscallInfo("io_uring_enter", FD, Hex, Hex, Hex, SigSet, Hex),
-	427: makeSyscallInfo("io_uring_register", FD, Hex, Hex, Hex),
-	428: makeSyscallInfo("open_tree", FD, Path, Hex),
-	429: makeSyscallInfo("move_mount", FD, Path, FD, Path, Hex),
-	430: makeSyscallInfo("fsopen", Path, Hex), // Not quite a path, but close.
-	431: makeSyscallInfo("fsconfig", FD, Hex, Hex, Hex, Hex),
-	432: makeSyscallInfo("fsmount", FD, Hex, Hex),
-	433: makeSyscallInfo("fspick", FD, Path, Hex),
-	434: makeSyscallInfo("pidfd_open", Hex, Hex),
-	435: makeSyscallInfo("clone3", Hex, Hex),
-}
diff --git a/pkg/sentry/strace/linux64_amd64.go b/pkg/sentry/strace/linux64_amd64.go
new file mode 100644
index 000000000..9fa2f0e16
--- /dev/null
+++ b/pkg/sentry/strace/linux64_amd64.go
@@ -0,0 +1,382 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build amd64
+
+package strace
+
+import (
+	"gvisor.dev/gvisor/pkg/abi"
+	"gvisor.dev/gvisor/pkg/sentry/arch"
+)
+
+// linuxAMD64 provides a mapping of the Linux amd64 syscalls and their argument
+// types for display / formatting.
+var linuxAMD64 = SyscallMap{
+	0:   makeSyscallInfo("read", FD, ReadBuffer, Hex),
+	1:   makeSyscallInfo("write", FD, WriteBuffer, Hex),
+	2:   makeSyscallInfo("open", Path, OpenFlags, Mode),
+	3:   makeSyscallInfo("close", FD),
+	4:   makeSyscallInfo("stat", Path, Stat),
+	5:   makeSyscallInfo("fstat", FD, Stat),
+	6:   makeSyscallInfo("lstat", Path, Stat),
+	7:   makeSyscallInfo("poll", PollFDs, Hex, Hex),
+	8:   makeSyscallInfo("lseek", Hex, Hex, Hex),
+	9:   makeSyscallInfo("mmap", Hex, Hex, Hex, Hex, FD, Hex),
+	10:  makeSyscallInfo("mprotect", Hex, Hex, Hex),
+	11:  makeSyscallInfo("munmap", Hex, Hex),
+	12:  makeSyscallInfo("brk", Hex),
+	13:  makeSyscallInfo("rt_sigaction", Signal, SigAction, PostSigAction),
+	14:  makeSyscallInfo("rt_sigprocmask", SignalMaskAction, SigSet, PostSigSet, Hex),
+	15:  makeSyscallInfo("rt_sigreturn"),
+	16:  makeSyscallInfo("ioctl", FD, Hex, Hex),
+	17:  makeSyscallInfo("pread64", FD, ReadBuffer, Hex, Hex),
+	18:  makeSyscallInfo("pwrite64", FD, WriteBuffer, Hex, Hex),
+	19:  makeSyscallInfo("readv", FD, ReadIOVec, Hex),
+	20:  makeSyscallInfo("writev", FD, WriteIOVec, Hex),
+	21:  makeSyscallInfo("access", Path, Oct),
+	22:  makeSyscallInfo("pipe", PipeFDs),
+	23:  makeSyscallInfo("select", Hex, SelectFDSet, SelectFDSet, SelectFDSet, Timeval),
+	24:  makeSyscallInfo("sched_yield"),
+	25:  makeSyscallInfo("mremap", Hex, Hex, Hex, Hex, Hex),
+	26:  makeSyscallInfo("msync", Hex, Hex, Hex),
+	27:  makeSyscallInfo("mincore", Hex, Hex, Hex),
+	28:  makeSyscallInfo("madvise", Hex, Hex, Hex),
+	29:  makeSyscallInfo("shmget", Hex, Hex, Hex),
+	30:  makeSyscallInfo("shmat", Hex, Hex, Hex),
+	31:  makeSyscallInfo("shmctl", Hex, Hex, Hex),
+	32:  makeSyscallInfo("dup", FD),
+	33:  makeSyscallInfo("dup2", FD, FD),
+	34:  makeSyscallInfo("pause"),
+	35:  makeSyscallInfo("nanosleep", Timespec, PostTimespec),
+	36:  makeSyscallInfo("getitimer", ItimerType, PostItimerVal),
+	37:  makeSyscallInfo("alarm", Hex),
+	38:  makeSyscallInfo("setitimer", ItimerType, ItimerVal, PostItimerVal),
+	39:  makeSyscallInfo("getpid"),
+	40:  makeSyscallInfo("sendfile", FD, FD, Hex, Hex),
+	41:  makeSyscallInfo("socket", SockFamily, SockType, SockProtocol),
+	42:  makeSyscallInfo("connect", FD, SockAddr, Hex),
+	43:  makeSyscallInfo("accept", FD, PostSockAddr, SockLen),
+	44:  makeSyscallInfo("sendto", FD, Hex, Hex, Hex, SockAddr, Hex),
+	45:  makeSyscallInfo("recvfrom", FD, Hex, Hex, Hex, PostSockAddr, SockLen),
+	46:  makeSyscallInfo("sendmsg", FD, SendMsgHdr, Hex),
+	47:  makeSyscallInfo("recvmsg", FD, RecvMsgHdr, Hex),
+	48:  makeSyscallInfo("shutdown", FD, Hex),
+	49:  makeSyscallInfo("bind", FD, SockAddr, Hex),
+	50:  makeSyscallInfo("listen", FD, Hex),
+	51:  makeSyscallInfo("getsockname", FD, PostSockAddr, SockLen),
+	52:  makeSyscallInfo("getpeername", FD, PostSockAddr, SockLen),
+	53:  makeSyscallInfo("socketpair", SockFamily, SockType, SockProtocol, Hex),
+	54:  makeSyscallInfo("setsockopt", FD, Hex, Hex, Hex, Hex),
+	55:  makeSyscallInfo("getsockopt", FD, Hex, Hex, Hex, Hex),
+	56:  makeSyscallInfo("clone", CloneFlags, Hex, Hex, Hex, Hex),
+	57:  makeSyscallInfo("fork"),
+	58:  makeSyscallInfo("vfork"),
+	59:  makeSyscallInfo("execve", Path, ExecveStringVector, ExecveStringVector),
+	60:  makeSyscallInfo("exit", Hex),
+	61:  makeSyscallInfo("wait4", Hex, Hex, Hex, Rusage),
+	62:  makeSyscallInfo("kill", Hex, Signal),
+	63:  makeSyscallInfo("uname", Uname),
+	64:  makeSyscallInfo("semget", Hex, Hex, Hex),
+	65:  makeSyscallInfo("semop", Hex, Hex, Hex),
+	66:  makeSyscallInfo("semctl", Hex, Hex, Hex, Hex),
+	67:  makeSyscallInfo("shmdt", Hex),
+	68:  makeSyscallInfo("msgget", Hex, Hex),
+	69:  makeSyscallInfo("msgsnd", Hex, Hex, Hex, Hex),
+	70:  makeSyscallInfo("msgrcv", Hex, Hex, Hex, Hex, Hex),
+	71:  makeSyscallInfo("msgctl", Hex, Hex, Hex),
+	72:  makeSyscallInfo("fcntl", FD, Hex, Hex),
+	73:  makeSyscallInfo("flock", FD, Hex),
+	74:  makeSyscallInfo("fsync", FD),
+	75:  makeSyscallInfo("fdatasync", FD),
+	76:  makeSyscallInfo("truncate", Path, Hex),
+	77:  makeSyscallInfo("ftruncate", FD, Hex),
+	78:  makeSyscallInfo("getdents", FD, Hex, Hex),
+	79:  makeSyscallInfo("getcwd", PostPath, Hex),
+	80:  makeSyscallInfo("chdir", Path),
+	81:  makeSyscallInfo("fchdir", FD),
+	82:  makeSyscallInfo("rename", Path, Path),
+	83:  makeSyscallInfo("mkdir", Path, Oct),
+	84:  makeSyscallInfo("rmdir", Path),
+	85:  makeSyscallInfo("creat", Path, Oct),
+	86:  makeSyscallInfo("link", Path, Path),
+	87:  makeSyscallInfo("unlink", Path),
+	88:  makeSyscallInfo("symlink", Path, Path),
+	89:  makeSyscallInfo("readlink", Path, ReadBuffer, Hex),
+	90:  makeSyscallInfo("chmod", Path, Mode),
+	91:  makeSyscallInfo("fchmod", FD, Mode),
+	92:  makeSyscallInfo("chown", Path, Hex, Hex),
+	93:  makeSyscallInfo("fchown", FD, Hex, Hex),
+	94:  makeSyscallInfo("lchown", Path, Hex, Hex),
+	95:  makeSyscallInfo("umask", Hex),
+	96:  makeSyscallInfo("gettimeofday", Timeval, Hex),
+	97:  makeSyscallInfo("getrlimit", Hex, Hex),
+	98:  makeSyscallInfo("getrusage", Hex, Rusage),
+	99:  makeSyscallInfo("sysinfo", Hex),
+	100: makeSyscallInfo("times", Hex),
+	101: makeSyscallInfo("ptrace", PtraceRequest, Hex, Hex, Hex),
+	102: makeSyscallInfo("getuid"),
+	103: makeSyscallInfo("syslog", Hex, Hex, Hex),
+	104: makeSyscallInfo("getgid"),
+	105: makeSyscallInfo("setuid", Hex),
+	106: makeSyscallInfo("setgid", Hex),
+	107: makeSyscallInfo("geteuid"),
+	108: makeSyscallInfo("getegid"),
+	109: makeSyscallInfo("setpgid", Hex, Hex),
+	110: makeSyscallInfo("getppid"),
+	111: makeSyscallInfo("getpgrp"),
+	112: makeSyscallInfo("setsid"),
+	113: makeSyscallInfo("setreuid", Hex, Hex),
+	114: makeSyscallInfo("setregid", Hex, Hex),
+	115: makeSyscallInfo("getgroups", Hex, Hex),
+	116: makeSyscallInfo("setgroups", Hex, Hex),
+	117: makeSyscallInfo("setresuid", Hex, Hex, Hex),
+	118: makeSyscallInfo("getresuid", Hex, Hex, Hex),
+	119: makeSyscallInfo("setresgid", Hex, Hex, Hex),
+	120: makeSyscallInfo("getresgid", Hex, Hex, Hex),
+	121: makeSyscallInfo("getpgid", Hex),
+	122: makeSyscallInfo("setfsuid", Hex),
+	123: makeSyscallInfo("setfsgid", Hex),
+	124: makeSyscallInfo("getsid", Hex),
+	125: makeSyscallInfo("capget", CapHeader, PostCapData),
+	126: makeSyscallInfo("capset", CapHeader, CapData),
+	127: makeSyscallInfo("rt_sigpending", Hex),
+	128: makeSyscallInfo("rt_sigtimedwait", SigSet, Hex, Timespec, Hex),
+	129: makeSyscallInfo("rt_sigqueueinfo", Hex, Signal, Hex),
+	130: makeSyscallInfo("rt_sigsuspend", Hex),
+	131: makeSyscallInfo("sigaltstack", Hex, Hex),
+	132: makeSyscallInfo("utime", Path, Utimbuf),
+	133: makeSyscallInfo("mknod", Path, Mode, Hex),
+	134: makeSyscallInfo("uselib", Hex),
+	135: makeSyscallInfo("personality", Hex),
+	136: makeSyscallInfo("ustat", Hex, Hex),
+	137: makeSyscallInfo("statfs", Path, Hex),
+	138: makeSyscallInfo("fstatfs", FD, Hex),
+	139: makeSyscallInfo("sysfs", Hex, Hex, Hex),
+	140: makeSyscallInfo("getpriority", Hex, Hex),
+	141: makeSyscallInfo("setpriority", Hex, Hex, Hex),
+	142: makeSyscallInfo("sched_setparam", Hex, Hex),
+	143: makeSyscallInfo("sched_getparam", Hex, Hex),
+	144: makeSyscallInfo("sched_setscheduler", Hex, Hex, Hex),
+	145: makeSyscallInfo("sched_getscheduler", Hex),
+	146: makeSyscallInfo("sched_get_priority_max", Hex),
+	147: makeSyscallInfo("sched_get_priority_min", Hex),
+	148: makeSyscallInfo("sched_rr_get_interval", Hex, Hex),
+	149: makeSyscallInfo("mlock", Hex, Hex),
+	150: makeSyscallInfo("munlock", Hex, Hex),
+	151: makeSyscallInfo("mlockall", Hex),
+	152: makeSyscallInfo("munlockall"),
+	153: makeSyscallInfo("vhangup"),
+	154: makeSyscallInfo("modify_ldt", Hex, Hex, Hex),
+	155: makeSyscallInfo("pivot_root", Path, Path),
+	156: makeSyscallInfo("_sysctl", Hex),
+	157: makeSyscallInfo("prctl", Hex, Hex, Hex, Hex, Hex),
+	158: makeSyscallInfo("arch_prctl", Hex, Hex),
+	159: makeSyscallInfo("adjtimex", Hex),
+	160: makeSyscallInfo("setrlimit", Hex, Hex),
+	161: makeSyscallInfo("chroot", Path),
+	162: makeSyscallInfo("sync"),
+	163: makeSyscallInfo("acct", Hex),
+	164: makeSyscallInfo("settimeofday", Timeval, Hex),
+	165: makeSyscallInfo("mount", Path, Path, Path, Hex, Path),
+	166: makeSyscallInfo("umount2", Path, Hex),
+	167: makeSyscallInfo("swapon", Hex, Hex),
+	168: makeSyscallInfo("swapoff", Hex),
+	169: makeSyscallInfo("reboot", Hex, Hex, Hex, Hex),
+	170: makeSyscallInfo("sethostname", Hex, Hex),
+	171: makeSyscallInfo("setdomainname", Hex, Hex),
+	172: makeSyscallInfo("iopl", Hex),
+	173: makeSyscallInfo("ioperm", Hex, Hex, Hex),
+	174: makeSyscallInfo("create_module", Path, Hex),
+	175: makeSyscallInfo("init_module", Hex, Hex, Hex),
+	176: makeSyscallInfo("delete_module", Hex, Hex),
+	177: makeSyscallInfo("get_kernel_syms", Hex),
+	// 178: query_module (only present in Linux < 2.6)
+	179: makeSyscallInfo("quotactl", Hex, Hex, Hex, Hex),
+	180: makeSyscallInfo("nfsservctl", Hex, Hex, Hex),
+	// 181: getpmsg (not implemented in the Linux kernel)
+	// 182: putpmsg (not implemented in the Linux kernel)
+	// 183: afs_syscall (not implemented in the Linux kernel)
+	// 184: tuxcall (not implemented in the Linux kernel)
+	// 185: security (not implemented in the Linux kernel)
+	186: makeSyscallInfo("gettid"),
+	187: makeSyscallInfo("readahead", Hex, Hex, Hex),
+	188: makeSyscallInfo("setxattr", Path, Path, Hex, Hex, Hex),
+	189: makeSyscallInfo("lsetxattr", Path, Path, Hex, Hex, Hex),
+	190: makeSyscallInfo("fsetxattr", FD, Path, Hex, Hex, Hex),
+	191: makeSyscallInfo("getxattr", Path, Path, Hex, Hex),
+	192: makeSyscallInfo("lgetxattr", Path, Path, Hex, Hex),
+	193: makeSyscallInfo("fgetxattr", FD, Path, Hex, Hex),
+	194: makeSyscallInfo("listxattr", Path, Path, Hex),
+	195: makeSyscallInfo("llistxattr", Path, Path, Hex),
+	196: makeSyscallInfo("flistxattr", FD, Path, Hex),
+	197: makeSyscallInfo("removexattr", Path, Path),
+	198: makeSyscallInfo("lremovexattr", Path, Path),
+	199: makeSyscallInfo("fremovexattr", FD, Path),
+	200: makeSyscallInfo("tkill", Hex, Signal),
+	201: makeSyscallInfo("time", Hex),
+	202: makeSyscallInfo("futex", Hex, FutexOp, Hex, Timespec, Hex, Hex),
+	203: makeSyscallInfo("sched_setaffinity", Hex, Hex, Hex),
+	204: makeSyscallInfo("sched_getaffinity", Hex, Hex, Hex),
+	205: makeSyscallInfo("set_thread_area", Hex),
+	206: makeSyscallInfo("io_setup", Hex, Hex),
+	207: makeSyscallInfo("io_destroy", Hex),
+	208: makeSyscallInfo("io_getevents", Hex, Hex, Hex, Hex, Timespec),
+	209: makeSyscallInfo("io_submit", Hex, Hex, Hex),
+	210: makeSyscallInfo("io_cancel", Hex, Hex, Hex),
+	211: makeSyscallInfo("get_thread_area", Hex),
+	212: makeSyscallInfo("lookup_dcookie", Hex, Hex, Hex),
+	213: makeSyscallInfo("epoll_create", Hex),
+	// 214: epoll_ctl_old (not implemented in the Linux kernel)
+	// 215: epoll_wait_old (not implemented in the Linux kernel)
+	216: makeSyscallInfo("remap_file_pages", Hex, Hex, Hex, Hex, Hex),
+	217: makeSyscallInfo("getdents64", FD, Hex, Hex),
+	218: makeSyscallInfo("set_tid_address", Hex),
+	219: makeSyscallInfo("restart_syscall"),
+	220: makeSyscallInfo("semtimedop", Hex, Hex, Hex, Hex),
+	221: makeSyscallInfo("fadvise64", FD, Hex, Hex, Hex),
+	222: makeSyscallInfo("timer_create", Hex, Hex, Hex),
+	223: makeSyscallInfo("timer_settime", Hex, Hex, ItimerSpec, PostItimerSpec),
+	224: makeSyscallInfo("timer_gettime", Hex, PostItimerSpec),
+	225: makeSyscallInfo("timer_getoverrun", Hex),
+	226: makeSyscallInfo("timer_delete", Hex),
+	227: makeSyscallInfo("clock_settime", Hex, Timespec),
+	228: makeSyscallInfo("clock_gettime", Hex, PostTimespec),
+	229: makeSyscallInfo("clock_getres", Hex, PostTimespec),
+	230: makeSyscallInfo("clock_nanosleep", Hex, Hex, Timespec, PostTimespec),
+	231: makeSyscallInfo("exit_group", Hex),
+	232: makeSyscallInfo("epoll_wait", Hex, Hex, Hex, Hex),
+	233: makeSyscallInfo("epoll_ctl", Hex, Hex, FD, Hex),
+	234: makeSyscallInfo("tgkill", Hex, Hex, Signal),
+	235: makeSyscallInfo("utimes", Path, Timeval),
+	// 236: vserver (not implemented in the Linux kernel)
+	237: makeSyscallInfo("mbind", Hex, Hex, Hex, Hex, Hex, Hex),
+	238: makeSyscallInfo("set_mempolicy", Hex, Hex, Hex),
+	239: makeSyscallInfo("get_mempolicy", Hex, Hex, Hex, Hex, Hex),
+	240: makeSyscallInfo("mq_open", Hex, Hex, Hex, Hex),
+	241: makeSyscallInfo("mq_unlink", Hex),
+	242: makeSyscallInfo("mq_timedsend", Hex, Hex, Hex, Hex, Hex),
+	243: makeSyscallInfo("mq_timedreceive", Hex, Hex, Hex, Hex, Hex),
+	244: makeSyscallInfo("mq_notify", Hex, Hex),
+	245: makeSyscallInfo("mq_getsetattr", Hex, Hex, Hex),
+	246: makeSyscallInfo("kexec_load", Hex, Hex, Hex, Hex),
+	247: makeSyscallInfo("waitid", Hex, Hex, Hex, Hex, Rusage),
+	248: makeSyscallInfo("add_key", Hex, Hex, Hex, Hex, Hex),
+	249: makeSyscallInfo("request_key", Hex, Hex, Hex, Hex),
+	250: makeSyscallInfo("keyctl", Hex, Hex, Hex, Hex, Hex),
+	251: makeSyscallInfo("ioprio_set", Hex, Hex, Hex),
+	252: makeSyscallInfo("ioprio_get", Hex, Hex),
+	253: makeSyscallInfo("inotify_init"),
+	254: makeSyscallInfo("inotify_add_watch", Hex, Path, Hex),
+	255: makeSyscallInfo("inotify_rm_watch", Hex, Hex),
+	256: makeSyscallInfo("migrate_pages", Hex, Hex, Hex, Hex),
+	257: makeSyscallInfo("openat", FD, Path, OpenFlags, Mode),
+	258: makeSyscallInfo("mkdirat", FD, Path, Hex),
+	259: makeSyscallInfo("mknodat", FD, Path, Mode, Hex),
+	260: makeSyscallInfo("fchownat", FD, Path, Hex, Hex, Hex),
+	261: makeSyscallInfo("futimesat", FD, Path, Hex),
+	262: makeSyscallInfo("newfstatat", FD, Path, Stat, Hex),
+	263: makeSyscallInfo("unlinkat", FD, Path, Hex),
+	264: makeSyscallInfo("renameat", FD, Path, Hex, Path),
+	265: makeSyscallInfo("linkat", FD, Path, Hex, Path, Hex),
+	266: makeSyscallInfo("symlinkat", Path, Hex, Path),
+	267: makeSyscallInfo("readlinkat", FD, Path, ReadBuffer, Hex),
+	268: makeSyscallInfo("fchmodat", FD, Path, Mode),
+	269: makeSyscallInfo("faccessat", FD, Path, Oct, Hex),
+	270: makeSyscallInfo("pselect6", Hex, SelectFDSet, SelectFDSet, SelectFDSet, Timespec, SigSet),
+	271: makeSyscallInfo("ppoll", PollFDs, Hex, Timespec, SigSet, Hex),
+	272: makeSyscallInfo("unshare", CloneFlags),
+	273: makeSyscallInfo("set_robust_list", Hex, Hex),
+	274: makeSyscallInfo("get_robust_list", Hex, Hex, Hex),
+	275: makeSyscallInfo("splice", FD, Hex, FD, Hex, Hex, Hex),
+	276: makeSyscallInfo("tee", FD, FD, Hex, Hex),
+	277: makeSyscallInfo("sync_file_range", FD, Hex, Hex, Hex),
+	278: makeSyscallInfo("vmsplice", FD, Hex, Hex, Hex),
+	279: makeSyscallInfo("move_pages", Hex, Hex, Hex, Hex, Hex, Hex),
+	280: makeSyscallInfo("utimensat", FD, Path, UTimeTimespec, Hex),
+	281: makeSyscallInfo("epoll_pwait", Hex, Hex, Hex, Hex, SigSet, Hex),
+	282: makeSyscallInfo("signalfd", Hex, Hex, Hex),
+	283: makeSyscallInfo("timerfd_create", Hex, Hex),
+	284: makeSyscallInfo("eventfd", Hex),
+	285: makeSyscallInfo("fallocate", FD, Hex, Hex, Hex),
+	286: makeSyscallInfo("timerfd_settime", FD, Hex, ItimerSpec, PostItimerSpec),
+	287: makeSyscallInfo("timerfd_gettime", FD, PostItimerSpec),
+	288: makeSyscallInfo("accept4", FD, PostSockAddr, SockLen, SockFlags),
+	289: makeSyscallInfo("signalfd4", Hex, Hex, Hex, Hex),
+	290: makeSyscallInfo("eventfd2", Hex, Hex),
+	291: makeSyscallInfo("epoll_create1", Hex),
+	292: makeSyscallInfo("dup3", FD, FD, Hex),
+	293: makeSyscallInfo("pipe2", PipeFDs, Hex),
+	294: makeSyscallInfo("inotify_init1", Hex),
+	295: makeSyscallInfo("preadv", FD, ReadIOVec, Hex, Hex),
+	296: makeSyscallInfo("pwritev", FD, WriteIOVec, Hex, Hex),
+	297: makeSyscallInfo("rt_tgsigqueueinfo", Hex, Hex, Signal, Hex),
+	298: makeSyscallInfo("perf_event_open", Hex, Hex, Hex, Hex, Hex),
+	299: makeSyscallInfo("recvmmsg", FD, Hex, Hex, Hex, Hex),
+	300: makeSyscallInfo("fanotify_init", Hex, Hex),
+	301: makeSyscallInfo("fanotify_mark", Hex, Hex, Hex, Hex, Hex),
+	302: makeSyscallInfo("prlimit64", Hex, Hex, Hex, Hex),
+	303: makeSyscallInfo("name_to_handle_at", FD, Hex, Hex, Hex, Hex),
+	304: makeSyscallInfo("open_by_handle_at", FD, Hex, Hex),
+	305: makeSyscallInfo("clock_adjtime", Hex, Hex),
+	306: makeSyscallInfo("syncfs", FD),
+	307: makeSyscallInfo("sendmmsg", FD, Hex, Hex, Hex),
+	308: makeSyscallInfo("setns", FD, Hex),
+	309: makeSyscallInfo("getcpu", Hex, Hex, Hex),
+	310: makeSyscallInfo("process_vm_readv", Hex, ReadIOVec, Hex, IOVec, Hex, Hex),
+	311: makeSyscallInfo("process_vm_writev", Hex, IOVec, Hex, WriteIOVec, Hex, Hex),
+	312: makeSyscallInfo("kcmp", Hex, Hex, Hex, Hex, Hex),
+	313: makeSyscallInfo("finit_module", Hex, Hex, Hex),
+	314: makeSyscallInfo("sched_setattr", Hex, Hex, Hex),
+	315: makeSyscallInfo("sched_getattr", Hex, Hex, Hex),
+	316: makeSyscallInfo("renameat2", FD, Path, Hex, Path, Hex),
+	317: makeSyscallInfo("seccomp", Hex, Hex, Hex),
+	318: makeSyscallInfo("getrandom", Hex, Hex, Hex),
+	319: makeSyscallInfo("memfd_create", Path, Hex), // Not quite a path, but close.
+	320: makeSyscallInfo("kexec_file_load", FD, FD, Hex, Hex, Hex),
+	321: makeSyscallInfo("bpf", Hex, Hex, Hex),
+	322: makeSyscallInfo("execveat", FD, Path, ExecveStringVector, ExecveStringVector, Hex),
+	323: makeSyscallInfo("userfaultfd", Hex),
+	324: makeSyscallInfo("membarrier", Hex, Hex),
+	325: makeSyscallInfo("mlock2", Hex, Hex, Hex),
+	326: makeSyscallInfo("copy_file_range", FD, Hex, FD, Hex, Hex, Hex),
+	327: makeSyscallInfo("preadv2", FD, ReadIOVec, Hex, Hex, Hex),
+	328: makeSyscallInfo("pwritev2", FD, WriteIOVec, Hex, Hex, Hex),
+	329: makeSyscallInfo("pkey_mprotect", Hex, Hex, Hex, Hex),
+	330: makeSyscallInfo("pkey_alloc", Hex, Hex),
+	331: makeSyscallInfo("pkey_free", Hex),
+	332: makeSyscallInfo("statx", FD, Path, Hex, Hex, Hex),
+	333: makeSyscallInfo("io_pgetevents", Hex, Hex, Hex, Hex, Timespec, SigSet),
+	334: makeSyscallInfo("rseq", Hex, Hex, Hex, Hex),
+	424: makeSyscallInfo("pidfd_send_signal", FD, Signal, Hex, Hex),
+	425: makeSyscallInfo("io_uring_setup", Hex, Hex),
+	426: makeSyscallInfo("io_uring_enter", FD, Hex, Hex, Hex, SigSet, Hex),
+	427: makeSyscallInfo("io_uring_register", FD, Hex, Hex, Hex),
+	428: makeSyscallInfo("open_tree", FD, Path, Hex),
+	429: makeSyscallInfo("move_mount", FD, Path, FD, Path, Hex),
+	430: makeSyscallInfo("fsopen", Path, Hex), // Not quite a path, but close.
+	431: makeSyscallInfo("fsconfig", FD, Hex, Hex, Hex, Hex),
+	432: makeSyscallInfo("fsmount", FD, Hex, Hex),
+	433: makeSyscallInfo("fspick", FD, Path, Hex),
+	434: makeSyscallInfo("pidfd_open", Hex, Hex),
+	435: makeSyscallInfo("clone3", Hex, Hex),
+}
+
+func init() {
+	syscallTables = append(syscallTables,
+		syscallTable{
+			os:       abi.Linux,
+			arch:     arch.AMD64,
+			syscalls: linuxAMD64})
+}
diff --git a/pkg/sentry/strace/linux64_arm64.go b/pkg/sentry/strace/linux64_arm64.go
new file mode 100644
index 000000000..c3ac5248d
--- /dev/null
+++ b/pkg/sentry/strace/linux64_arm64.go
@@ -0,0 +1,323 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build arm64
+
+package strace
+
+import (
+	"gvisor.dev/gvisor/pkg/abi"
+	"gvisor.dev/gvisor/pkg/sentry/arch"
+)
+
+// linuxARM64 provides a mapping of the Linux arm64 syscalls and their argument
+// types for display / formatting.
+var linuxARM64 = SyscallMap{
+	0:   makeSyscallInfo("io_setup", Hex, Hex),
+	1:   makeSyscallInfo("io_destroy", Hex),
+	2:   makeSyscallInfo("io_submit", Hex, Hex, Hex),
+	3:   makeSyscallInfo("io_cancel", Hex, Hex, Hex),
+	4:   makeSyscallInfo("io_getevents", Hex, Hex, Hex, Hex, Timespec),
+	5:   makeSyscallInfo("setxattr", Path, Path, Hex, Hex, Hex),
+	6:   makeSyscallInfo("lsetxattr", Path, Path, Hex, Hex, Hex),
+	7:   makeSyscallInfo("fsetxattr", FD, Path, Hex, Hex, Hex),
+	8:   makeSyscallInfo("getxattr", Path, Path, Hex, Hex),
+	9:   makeSyscallInfo("lgetxattr", Path, Path, Hex, Hex),
+	10:  makeSyscallInfo("fgetxattr", FD, Path, Hex, Hex),
+	11:  makeSyscallInfo("listxattr", Path, Path, Hex),
+	12:  makeSyscallInfo("llistxattr", Path, Path, Hex),
+	13:  makeSyscallInfo("flistxattr", FD, Path, Hex),
+	14:  makeSyscallInfo("removexattr", Path, Path),
+	15:  makeSyscallInfo("lremovexattr", Path, Path),
+	16:  makeSyscallInfo("fremovexattr", FD, Path),
+	17:  makeSyscallInfo("getcwd", PostPath, Hex),
+	18:  makeSyscallInfo("lookup_dcookie", Hex, Hex, Hex),
+	19:  makeSyscallInfo("eventfd2", Hex, Hex),
+	20:  makeSyscallInfo("epoll_create1", Hex),
+	21:  makeSyscallInfo("epoll_ctl", Hex, Hex, FD, Hex),
+	22:  makeSyscallInfo("epoll_pwait", Hex, Hex, Hex, Hex, SigSet, Hex),
+	23:  makeSyscallInfo("dup", FD),
+	24:  makeSyscallInfo("dup3", FD, FD, Hex),
+	25:  makeSyscallInfo("fcntl", FD, Hex, Hex),
+	26:  makeSyscallInfo("inotify_init1", Hex),
+	27:  makeSyscallInfo("inotify_add_watch", Hex, Path, Hex),
+	28:  makeSyscallInfo("inotify_rm_watch", Hex, Hex),
+	29:  makeSyscallInfo("ioctl", FD, Hex, Hex),
+	30:  makeSyscallInfo("ioprio_set", Hex, Hex, Hex),
+	31:  makeSyscallInfo("ioprio_get", Hex, Hex),
+	32:  makeSyscallInfo("flock", FD, Hex),
+	33:  makeSyscallInfo("mknodat", FD, Path, Mode, Hex),
+	34:  makeSyscallInfo("mkdirat", FD, Path, Hex),
+	35:  makeSyscallInfo("unlinkat", FD, Path, Hex),
+	36:  makeSyscallInfo("symlinkat", Path, Hex, Path),
+	37:  makeSyscallInfo("linkat", FD, Path, Hex, Path, Hex),
+	38:  makeSyscallInfo("renameat", FD, Path, Hex, Path),
+	39:  makeSyscallInfo("umount2", Path, Hex),
+	40:  makeSyscallInfo("mount", Path, Path, Path, Hex, Path),
+	41:  makeSyscallInfo("pivot_root", Path, Path),
+	42:  makeSyscallInfo("nfsservctl", Hex, Hex, Hex),
+	43:  makeSyscallInfo("statfs", Path, Hex),
+	44:  makeSyscallInfo("fstatfs", FD, Hex),
+	45:  makeSyscallInfo("truncate", Path, Hex),
+	46:  makeSyscallInfo("ftruncate", FD, Hex),
+	47:  makeSyscallInfo("fallocate", FD, Hex, Hex, Hex),
+	48:  makeSyscallInfo("faccessat", FD, Path, Oct, Hex),
+	49:  makeSyscallInfo("chdir", Path),
+	50:  makeSyscallInfo("fchdir", FD),
+	51:  makeSyscallInfo("chroot", Path),
+	52:  makeSyscallInfo("fchmod", FD, Mode),
+	53:  makeSyscallInfo("fchmodat", FD, Path, Mode),
+	54:  makeSyscallInfo("fchownat", FD, Path, Hex, Hex, Hex),
+	55:  makeSyscallInfo("fchown", FD, Hex, Hex),
+	56:  makeSyscallInfo("openat", FD, Path, OpenFlags, Mode),
+	57:  makeSyscallInfo("close", FD),
+	58:  makeSyscallInfo("vhangup"),
+	59:  makeSyscallInfo("pipe2", PipeFDs, Hex),
+	60:  makeSyscallInfo("quotactl", Hex, Hex, Hex, Hex),
+	61:  makeSyscallInfo("getdents64", FD, Hex, Hex),
+	62:  makeSyscallInfo("lseek", Hex, Hex, Hex),
+	63:  makeSyscallInfo("read", FD, ReadBuffer, Hex),
+	64:  makeSyscallInfo("write", FD, WriteBuffer, Hex),
+	65:  makeSyscallInfo("readv", FD, ReadIOVec, Hex),
+	66:  makeSyscallInfo("writev", FD, WriteIOVec, Hex),
+	67:  makeSyscallInfo("pread64", FD, ReadBuffer, Hex, Hex),
+	68:  makeSyscallInfo("pwrite64", FD, WriteBuffer, Hex, Hex),
+	69:  makeSyscallInfo("preadv", FD, ReadIOVec, Hex, Hex),
+	70:  makeSyscallInfo("pwritev", FD, WriteIOVec, Hex, Hex),
+	71:  makeSyscallInfo("sendfile", FD, FD, Hex, Hex),
+	72:  makeSyscallInfo("pselect6", Hex, Hex, Hex, Hex, Hex, Hex),
+	73:  makeSyscallInfo("ppoll", PollFDs, Hex, Timespec, SigSet, Hex),
+	74:  makeSyscallInfo("signalfd4", Hex, Hex, Hex, Hex),
+	75:  makeSyscallInfo("vmsplice", FD, Hex, Hex, Hex),
+	76:  makeSyscallInfo("splice", FD, Hex, FD, Hex, Hex, Hex),
+	77:  makeSyscallInfo("tee", FD, FD, Hex, Hex),
+	78:  makeSyscallInfo("readlinkat", FD, Path, ReadBuffer, Hex),
+	79:  makeSyscallInfo("fstatat", FD, Path, Stat, Hex),
+	80:  makeSyscallInfo("fstat", FD, Stat),
+	81:  makeSyscallInfo("sync"),
+	82:  makeSyscallInfo("fsync", FD),
+	83:  makeSyscallInfo("fdatasync", FD),
+	84:  makeSyscallInfo("sync_file_range", FD, Hex, Hex, Hex),
+	85:  makeSyscallInfo("timerfd_create", Hex, Hex),
+	86:  makeSyscallInfo("timerfd_settime", FD, Hex, ItimerSpec, PostItimerSpec),
+	87:  makeSyscallInfo("timerfd_gettime", FD, PostItimerSpec),
+	88:  makeSyscallInfo("utimensat", FD, Path, UTimeTimespec, Hex),
+	89:  makeSyscallInfo("acct", Hex),
+	90:  makeSyscallInfo("capget", CapHeader, PostCapData),
+	91:  makeSyscallInfo("capset", CapHeader, CapData),
+	92:  makeSyscallInfo("personality", Hex),
+	93:  makeSyscallInfo("exit", Hex),
+	94:  makeSyscallInfo("exit_group", Hex),
+	95:  makeSyscallInfo("waitid", Hex, Hex, Hex, Hex, Rusage),
+	96:  makeSyscallInfo("set_tid_address", Hex),
+	97:  makeSyscallInfo("unshare", CloneFlags),
+	98:  makeSyscallInfo("futex", Hex, FutexOp, Hex, Timespec, Hex, Hex),
+	99:  makeSyscallInfo("set_robust_list", Hex, Hex),
+	100: makeSyscallInfo("get_robust_list", Hex, Hex, Hex),
+	101: makeSyscallInfo("nanosleep", Timespec, PostTimespec),
+	102: makeSyscallInfo("getitimer", ItimerType, PostItimerVal),
+	103: makeSyscallInfo("setitimer", ItimerType, ItimerVal, PostItimerVal),
+	104: makeSyscallInfo("kexec_load", Hex, Hex, Hex, Hex),
+	105: makeSyscallInfo("init_module", Hex, Hex, Hex),
+	106: makeSyscallInfo("delete_module", Hex, Hex),
+	107: makeSyscallInfo("timer_create", Hex, Hex, Hex),
+	108: makeSyscallInfo("timer_gettime", Hex, PostItimerSpec),
+	109: makeSyscallInfo("timer_getoverrun", Hex),
+	110: makeSyscallInfo("timer_settime", Hex, Hex, ItimerSpec, PostItimerSpec),
+	111: makeSyscallInfo("timer_delete", Hex),
+	112: makeSyscallInfo("clock_settime", Hex, Timespec),
+	113: makeSyscallInfo("clock_gettime", Hex, PostTimespec),
+	114: makeSyscallInfo("clock_getres", Hex, PostTimespec),
+	115: makeSyscallInfo("clock_nanosleep", Hex, Hex, Timespec, PostTimespec),
+	116: makeSyscallInfo("syslog", Hex, Hex, Hex),
+	117: makeSyscallInfo("ptrace", PtraceRequest, Hex, Hex, Hex),
+	118: makeSyscallInfo("sched_setparam", Hex, Hex),
+	119: makeSyscallInfo("sched_setscheduler", Hex, Hex, Hex),
+	120: makeSyscallInfo("sched_getscheduler", Hex),
+	121: makeSyscallInfo("sched_getparam", Hex, Hex),
+	122: makeSyscallInfo("sched_setaffinity", Hex, Hex, Hex),
+	123: makeSyscallInfo("sched_getaffinity", Hex, Hex, Hex),
+	124: makeSyscallInfo("sched_yield"),
+	125: makeSyscallInfo("sched_get_priority_max", Hex),
+	126: makeSyscallInfo("sched_get_priority_min", Hex),
+	127: makeSyscallInfo("sched_rr_get_interval", Hex, Hex),
+	128: makeSyscallInfo("restart_syscall"),
+	129: makeSyscallInfo("kill", Hex, Signal),
+	130: makeSyscallInfo("tkill", Hex, Signal),
+	131: makeSyscallInfo("tgkill", Hex, Hex, Signal),
+	132: makeSyscallInfo("sigaltstack", Hex, Hex),
+	133: makeSyscallInfo("rt_sigsuspend", Hex),
+	134: makeSyscallInfo("rt_sigaction", Signal, SigAction, PostSigAction),
+	135: makeSyscallInfo("rt_sigprocmask", SignalMaskAction, SigSet, PostSigSet, Hex),
+	136: makeSyscallInfo("rt_sigpending", Hex),
+	137: makeSyscallInfo("rt_sigtimedwait", SigSet, Hex, Timespec, Hex),
+	138: makeSyscallInfo("rt_sigqueueinfo", Hex, Signal, Hex),
+	139: makeSyscallInfo("rt_sigreturn"),
+	140: makeSyscallInfo("setpriority", Hex, Hex, Hex),
+	141: makeSyscallInfo("getpriority", Hex, Hex),
+	142: makeSyscallInfo("reboot", Hex, Hex, Hex, Hex),
+	143: makeSyscallInfo("setregid", Hex, Hex),
+	144: makeSyscallInfo("setgid", Hex),
+	145: makeSyscallInfo("setreuid", Hex, Hex),
+	146: makeSyscallInfo("setuid", Hex),
+	147: makeSyscallInfo("setresuid", Hex, Hex, Hex),
+	148: makeSyscallInfo("getresuid", Hex, Hex, Hex),
+	149: makeSyscallInfo("setresgid", Hex, Hex, Hex),
+	150: makeSyscallInfo("getresgid", Hex, Hex, Hex),
+	151: makeSyscallInfo("setfsuid", Hex),
+	152: makeSyscallInfo("setfsgid", Hex),
+	153: makeSyscallInfo("times", Hex),
+	154: makeSyscallInfo("setpgid", Hex, Hex),
+	155: makeSyscallInfo("getpgid", Hex),
+	156: makeSyscallInfo("getsid", Hex),
+	157: makeSyscallInfo("setsid"),
+	158: makeSyscallInfo("getgroups", Hex, Hex),
+	159: makeSyscallInfo("setgroups", Hex, Hex),
+	160: makeSyscallInfo("uname", Uname),
+	161: makeSyscallInfo("sethostname", Hex, Hex),
+	162: makeSyscallInfo("setdomainname", Hex, Hex),
+	163: makeSyscallInfo("getrlimit", Hex, Hex),
+	164: makeSyscallInfo("setrlimit", Hex, Hex),
+	165: makeSyscallInfo("getrusage", Hex, Rusage),
+	166: makeSyscallInfo("umask", Hex),
+	167: makeSyscallInfo("prctl", Hex, Hex, Hex, Hex, Hex),
+	168: makeSyscallInfo("getcpu", Hex, Hex, Hex),
+	169: makeSyscallInfo("gettimeofday", Timeval, Hex),
+	170: makeSyscallInfo("settimeofday", Timeval, Hex),
+	171: makeSyscallInfo("adjtimex", Hex),
+	172: makeSyscallInfo("getpid"),
+	173: makeSyscallInfo("getppid"),
+	174: makeSyscallInfo("getuid"),
+	175: makeSyscallInfo("geteuid"),
+	176: makeSyscallInfo("getgid"),
+	177: makeSyscallInfo("getegid"),
+	178: makeSyscallInfo("gettid"),
+	179: makeSyscallInfo("sysinfo", Hex),
+	180: makeSyscallInfo("mq_open", Hex, Hex, Hex, Hex),
+	181: makeSyscallInfo("mq_unlink", Hex),
+	182: makeSyscallInfo("mq_timedsend", Hex, Hex, Hex, Hex, Hex),
+	183: makeSyscallInfo("mq_timedreceive", Hex, Hex, Hex, Hex, Hex),
+	184: makeSyscallInfo("mq_notify", Hex, Hex),
+	185: makeSyscallInfo("mq_getsetattr", Hex, Hex, Hex),
+	186: makeSyscallInfo("msgget", Hex, Hex),
+	187: makeSyscallInfo("msgctl", Hex, Hex, Hex),
+	188: makeSyscallInfo("msgrcv", Hex, Hex, Hex, Hex, Hex),
+	189: makeSyscallInfo("msgsnd", Hex, Hex, Hex, Hex),
+	190: makeSyscallInfo("semget", Hex, Hex, Hex),
+	191: makeSyscallInfo("semctl", Hex, Hex, Hex, Hex),
+	192: makeSyscallInfo("semtimedop", Hex, Hex, Hex, Hex),
+	193: makeSyscallInfo("semop", Hex, Hex, Hex),
+	194: makeSyscallInfo("shmget", Hex, Hex, Hex),
+	195: makeSyscallInfo("shmctl", Hex, Hex, Hex),
+	196: makeSyscallInfo("shmat", Hex, Hex, Hex),
+	197: makeSyscallInfo("shmdt", Hex),
+	198: makeSyscallInfo("socket", SockFamily, SockType, SockProtocol),
+	199: makeSyscallInfo("socketpair", SockFamily, SockType, SockProtocol, Hex),
+	200: makeSyscallInfo("bind", FD, SockAddr, Hex),
+	201: makeSyscallInfo("listen", FD, Hex),
+	202: makeSyscallInfo("accept", FD, PostSockAddr, SockLen),
+	203: makeSyscallInfo("connect", FD, SockAddr, Hex),
+	204: makeSyscallInfo("getsockname", FD, PostSockAddr, SockLen),
+	205: makeSyscallInfo("getpeername", FD, PostSockAddr, SockLen),
+	206: makeSyscallInfo("sendto", FD, Hex, Hex, Hex, SockAddr, Hex),
+	207: makeSyscallInfo("recvfrom", FD, Hex, Hex, Hex, PostSockAddr, SockLen),
+	208: makeSyscallInfo("setsockopt", FD, Hex, Hex, Hex, Hex),
+	209: makeSyscallInfo("getsockopt", FD, Hex, Hex, Hex, Hex),
+	210: makeSyscallInfo("shutdown", FD, Hex),
+	211: makeSyscallInfo("sendmsg", FD, SendMsgHdr, Hex),
+	212: makeSyscallInfo("recvmsg", FD, RecvMsgHdr, Hex),
+	213: makeSyscallInfo("readahead", Hex, Hex, Hex),
+	214: makeSyscallInfo("brk", Hex),
+	215: makeSyscallInfo("munmap", Hex, Hex),
+	216: makeSyscallInfo("mremap", Hex, Hex, Hex, Hex, Hex),
+	217: makeSyscallInfo("add_key", Hex, Hex, Hex, Hex, Hex),
+	218: makeSyscallInfo("request_key", Hex, Hex, Hex, Hex),
+	219: makeSyscallInfo("keyctl", Hex, Hex, Hex, Hex, Hex),
+	220: makeSyscallInfo("clone", CloneFlags, Hex, Hex, Hex, Hex),
+	221: makeSyscallInfo("execve", Path, ExecveStringVector, ExecveStringVector),
+	222: makeSyscallInfo("mmap", Hex, Hex, Hex, Hex, FD, Hex),
+	223: makeSyscallInfo("fadvise64", FD, Hex, Hex, Hex),
+	224: makeSyscallInfo("swapon", Hex, Hex),
+	225: makeSyscallInfo("swapoff", Hex),
+	226: makeSyscallInfo("mprotect", Hex, Hex, Hex),
+	227: makeSyscallInfo("msync", Hex, Hex, Hex),
+	228: makeSyscallInfo("mlock", Hex, Hex),
+	229: makeSyscallInfo("munlock", Hex, Hex),
+	230: makeSyscallInfo("mlockall", Hex),
+	231: makeSyscallInfo("munlockall"),
+	232: makeSyscallInfo("mincore", Hex, Hex, Hex),
+	233: makeSyscallInfo("madvise", Hex, Hex, Hex),
+	234: makeSyscallInfo("remap_file_pages", Hex, Hex, Hex, Hex, Hex),
+	235: makeSyscallInfo("mbind", Hex, Hex, Hex, Hex, Hex, Hex),
+	236: makeSyscallInfo("get_mempolicy", Hex, Hex, Hex, Hex, Hex),
+	237: makeSyscallInfo("set_mempolicy", Hex, Hex, Hex),
+	238: makeSyscallInfo("migrate_pages", Hex, Hex, Hex, Hex),
+	239: makeSyscallInfo("move_pages", Hex, Hex, Hex, Hex, Hex, Hex),
+	240: makeSyscallInfo("rt_tgsigqueueinfo", Hex, Hex, Signal, Hex),
+	241: makeSyscallInfo("perf_event_open", Hex, Hex, Hex, Hex, Hex),
+	242: makeSyscallInfo("accept4", FD, PostSockAddr, SockLen, SockFlags),
+	243: makeSyscallInfo("recvmmsg", FD, Hex, Hex, Hex, Hex),
+
+	260: makeSyscallInfo("wait4", Hex, Hex, Hex, Rusage),
+	261: makeSyscallInfo("prlimit64", Hex, Hex, Hex, Hex),
+	262: makeSyscallInfo("fanotify_init", Hex, Hex),
+	263: makeSyscallInfo("fanotify_mark", Hex, Hex, Hex, Hex, Hex),
+	264: makeSyscallInfo("name_to_handle_at", FD, Hex, Hex, Hex, Hex),
+	265: makeSyscallInfo("open_by_handle_at", FD, Hex, Hex),
+	266: makeSyscallInfo("clock_adjtime", Hex, Hex),
+	267: makeSyscallInfo("syncfs", FD),
+	268: makeSyscallInfo("setns", FD, Hex),
+	269: makeSyscallInfo("sendmmsg", FD, Hex, Hex, Hex),
+	270: makeSyscallInfo("process_vm_readv", Hex, ReadIOVec, Hex, IOVec, Hex, Hex),
+	271: makeSyscallInfo("process_vm_writev", Hex, IOVec, Hex, WriteIOVec, Hex, Hex),
+	272: makeSyscallInfo("kcmp", Hex, Hex, Hex, Hex, Hex),
+	273: makeSyscallInfo("finit_module", Hex, Hex, Hex),
+	274: makeSyscallInfo("sched_setattr", Hex, Hex, Hex),
+	275: makeSyscallInfo("sched_getattr", Hex, Hex, Hex),
+	276: makeSyscallInfo("renameat2", FD, Path, Hex, Path, Hex),
+	277: makeSyscallInfo("seccomp", Hex, Hex, Hex),
+	278: makeSyscallInfo("getrandom", Hex, Hex, Hex),
+	279: makeSyscallInfo("memfd_create", Path, Hex),
+	280: makeSyscallInfo("bpf", Hex, Hex, Hex),
+	281: makeSyscallInfo("execveat", FD, Path, Hex, Hex, Hex),
+	282: makeSyscallInfo("userfaultfd", Hex),
+	283: makeSyscallInfo("membarrier", Hex),
+	284: makeSyscallInfo("mlock2", Hex, Hex, Hex),
+	285: makeSyscallInfo("copy_file_range", FD, Hex, FD, Hex, Hex, Hex),
+	286: makeSyscallInfo("preadv2", FD, ReadIOVec, Hex, Hex, Hex),
+	287: makeSyscallInfo("pwritev2", FD, WriteIOVec, Hex, Hex, Hex),
+	291: makeSyscallInfo("statx", FD, Path, Hex, Hex, Hex),
+	292: makeSyscallInfo("io_pgetevents", Hex, Hex, Hex, Hex, Timespec, SigSet),
+	293: makeSyscallInfo("rseq", Hex, Hex, Hex, Hex),
+	424: makeSyscallInfo("pidfd_send_signal", FD, Signal, Hex, Hex),
+	425: makeSyscallInfo("io_uring_setup", Hex, Hex),
+	426: makeSyscallInfo("io_uring_enter", FD, Hex, Hex, Hex, SigSet, Hex),
+	427: makeSyscallInfo("io_uring_register", FD, Hex, Hex, Hex),
+	428: makeSyscallInfo("open_tree", FD, Path, Hex),
+	429: makeSyscallInfo("move_mount", FD, Path, FD, Path, Hex),
+	430: makeSyscallInfo("fsopen", Path, Hex), // Not quite a path, but close.
+	431: makeSyscallInfo("fsconfig", FD, Hex, Hex, Hex, Hex),
+	432: makeSyscallInfo("fsmount", FD, Hex, Hex),
+	433: makeSyscallInfo("fspick", FD, Path, Hex),
+	434: makeSyscallInfo("pidfd_open", Hex, Hex),
+	435: makeSyscallInfo("clone3", Hex, Hex),
+}
+
+func init() {
+	syscallTables = append(syscallTables,
+		syscallTable{
+			os:       abi.Linux,
+			arch:     arch.ARM64,
+			syscalls: linuxARM64})
+}
diff --git a/pkg/sentry/strace/syscalls.go b/pkg/sentry/strace/syscalls.go
index e5d486c4e..24e29a2ba 100644
--- a/pkg/sentry/strace/syscalls.go
+++ b/pkg/sentry/strace/syscalls.go
@@ -250,14 +250,7 @@ type syscallTable struct {
 	syscalls SyscallMap
 }
 
-// syscallTables contains all syscall tables.
-var syscallTables = []syscallTable{
-	{
-		os:       abi.Linux,
-		arch:     arch.AMD64,
-		syscalls: linuxAMD64,
-	},
-}
+var syscallTables []syscallTable
 
 // Lookup returns the SyscallMap for the OS/Arch combination. The returned map
 // must not be changed.
-- 
cgit v1.2.3


From 08a97a6d193f46cd547fadae3bb4125cc788543b Mon Sep 17 00:00:00 2001
From: Marek Majkowski <marek@cloudflare.com>
Date: Thu, 2 Jan 2020 12:09:24 +0100
Subject: #1398 - send ACK when available buffer space gets larger than 1 MSS

When receiving data, netstack avoids sending spurious acks. When
user does recv() should netstack send ack telling the sender that
the window was increased? It depends. Before this patch, netstack
_will_ send the ack in the case when window was zero or window >>
scale was zero. Basically - when recv space increased from zero.

This is not working right with silly-window-avoidance on the sender
side. Some network stacks refuse to transmit segments, that will fill
the window but are below MSS. Before this patch, this confuses
netstack. On one hand if the window was like 3 bytes, netstack
will _not_ send ack if the window increases. On the other hand
sending party will refuse to transmit 3-byte packet.

This patch changes that, making netstack will send an ACK when
the available buffer size increases to or above 1*MSS. This will
inform other party buffer is large enough, and hopefully uncork it.


Signed-off-by: Marek Majkowski <marek@cloudflare.com>
---
 pkg/tcpip/transport/tcp/endpoint.go |  30 +++++---
 pkg/tcpip/transport/tcp/rcv.go      |   6 --
 pkg/tcpip/transport/tcp/tcp_test.go | 139 ++++++++++++++++++++++++++++++++++++
 3 files changed, 161 insertions(+), 14 deletions(-)

diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index fe629aa40..5d42f8045 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -955,10 +955,20 @@ func (e *endpoint) readLocked() (buffer.View, *tcpip.Error) {
 	}
 
 	e.rcvBufUsed -= len(v)
+
+	avail := e.receiveBufferAvailableLocked()
+
+	// If the window was small before, lower than MSS, send immediate
+	// ack. Without this, the sender might be stuck  waiting for the
+	// window to grow, while we think the window is non-zero so we
+	// don't need to send acks. To avoid silly window syndrome, send
+	// ack only when the window grows above one MSS.
+	crossedMSS := avail-len(v) < int(e.amss) && avail >= int(e.amss)
+
 	// If the window was zero before this read and if the read freed up
 	// enough buffer space for the scaled window to be non-zero then notify
 	// the protocol goroutine to send a window update.
-	if e.zeroWindow && !e.zeroReceiveWindow(e.rcv.rcvWndScale) {
+	if (e.zeroWindow && !e.zeroReceiveWindow(e.rcv.rcvWndScale)) || crossedMSS {
 		e.zeroWindow = false
 		e.notifyProtocolGoroutine(notifyNonZeroReceiveWindow)
 	}
@@ -1138,11 +1148,8 @@ func (e *endpoint) Peek(vec [][]byte) (int64, tcpip.ControlMessages, *tcpip.Erro
 //
 // It must be called with rcvListMu held.
 func (e *endpoint) zeroReceiveWindow(scale uint8) bool {
-	if e.rcvBufUsed >= e.rcvBufSize {
-		return true
-	}
-
-	return ((e.rcvBufSize - e.rcvBufUsed) >> scale) == 0
+	avail := e.receiveBufferAvailableLocked()
+	return (avail >> scale) == 0
 }
 
 // SetSockOptInt sets a socket option.
@@ -1181,9 +1188,16 @@ func (e *endpoint) SetSockOptInt(opt tcpip.SockOpt, v int) *tcpip.Error {
 			size = math.MaxInt32 / 2
 		}
 
+		availBefore := e.receiveBufferAvailableLocked()
 		e.rcvBufSize = size
+		availAfter := e.receiveBufferAvailableLocked()
+
 		e.rcvAutoParams.disabled = true
-		if e.zeroWindow && !e.zeroReceiveWindow(scale) {
+
+		// Immediatelly send ACK in two cases: when the buffer
+		// grows so that it leaves zero-window state, when the
+		// buffer grows from small < MSS to >= MSS.
+		if (e.zeroWindow && !e.zeroReceiveWindow(scale)) || (availBefore < int(e.amss) && availAfter >= int(e.amss)) {
 			e.zeroWindow = false
 			mask |= notifyNonZeroReceiveWindow
 		}
@@ -2229,7 +2243,7 @@ func (e *endpoint) readyToRead(s *segment) {
 		// we set the zero window before we deliver the segment to ensure
 		// that a subsequent read of the segment will correctly trigger
 		// a non-zero notification.
-		if avail := e.receiveBufferAvailableLocked(); avail>>e.rcv.rcvWndScale == 0 {
+		if e.zeroReceiveWindow(e.rcv.rcvWndScale) {
 			e.stats.ReceiveErrors.ZeroRcvWindowState.Increment()
 			e.zeroWindow = true
 		}
diff --git a/pkg/tcpip/transport/tcp/rcv.go b/pkg/tcpip/transport/tcp/rcv.go
index 0a5534959..05c8488f8 100644
--- a/pkg/tcpip/transport/tcp/rcv.go
+++ b/pkg/tcpip/transport/tcp/rcv.go
@@ -98,12 +98,6 @@ func (r *receiver) getSendParams() (rcvNxt seqnum.Value, rcvWnd seqnum.Size) {
 // in such cases we may need to send an ack to indicate to our peer that it can
 // resume sending data.
 func (r *receiver) nonZeroWindow() {
-	if (r.rcvAcc-r.rcvNxt)>>r.rcvWndScale != 0 {
-		// We never got around to announcing a zero window size, so we
-		// don't need to immediately announce a nonzero one.
-		return
-	}
-
 	// Immediately send an ack.
 	r.ep.snd.sendAck()
 }
diff --git a/pkg/tcpip/transport/tcp/tcp_test.go b/pkg/tcpip/transport/tcp/tcp_test.go
index e8fe4dab5..a05365c6a 100644
--- a/pkg/tcpip/transport/tcp/tcp_test.go
+++ b/pkg/tcpip/transport/tcp/tcp_test.go
@@ -6561,3 +6561,142 @@ func TestKeepaliveWithUserTimeout(t *testing.T) {
 		t.Errorf("got c.Stack().Stats().TCP.EstablishedTimedout = %v, want = %v", got, want)
 	}
 }
+
+func TestIncreaseWindowOnReceive(t *testing.T) {
+	// This test ensures that the endpoint sends an ack,
+	// after recv() when the window grows to more than 1 MSS.
+	c := context.New(t, defaultMTU)
+	defer c.Cleanup()
+
+	const rcvBuf = 65535 * 10
+	c.CreateConnected(789, 30000, rcvBuf)
+
+	// Write chunks of ~30000 bytes. It's important that two
+	// payloads make it equal or longer than MSS.
+	remain := rcvBuf
+	sent := 0
+	data := make([]byte, defaultMTU/2)
+	lastWnd := uint16(0)
+
+	for remain > len(data) {
+		c.SendPacket(data, &context.Headers{
+			SrcPort: context.TestPort,
+			DstPort: c.Port,
+			Flags:   header.TCPFlagAck,
+			SeqNum:  seqnum.Value(790 + sent),
+			AckNum:  c.IRS.Add(1),
+			RcvWnd:  30000,
+		})
+		sent += len(data)
+		remain -= len(data)
+
+		lastWnd = uint16(remain)
+		if remain > 0xffff {
+			lastWnd = 0xffff
+		}
+		checker.IPv4(t, c.GetPacket(),
+			checker.PayloadLen(header.TCPMinimumSize),
+			checker.TCP(
+				checker.DstPort(context.TestPort),
+				checker.SeqNum(uint32(c.IRS)+1),
+				checker.AckNum(uint32(790+sent)),
+				checker.Window(lastWnd),
+				checker.TCPFlags(header.TCPFlagAck),
+			),
+		)
+	}
+
+	if lastWnd == 0xffff || lastWnd == 0 {
+		t.Fatalf("expected small, non-zero window: %d", lastWnd)
+	}
+
+	// We now have < 1 MSS in the buffer space.  Read the data! An
+	// ack should be sent in response to that. The window was not
+	// zero, but it grew to larger than MSS.
+	_, _, err := c.EP.Read(nil)
+	if err != nil {
+		t.Fatalf("Read failed: %v", err)
+	}
+
+	_, _, err = c.EP.Read(nil)
+	if err != nil {
+		t.Fatalf("Read failed: %v", err)
+	}
+
+	// After reading two packets, we surely crossed MSS. See the ack:
+	checker.IPv4(t, c.GetPacket(),
+		checker.PayloadLen(header.TCPMinimumSize),
+		checker.TCP(
+			checker.DstPort(context.TestPort),
+			checker.SeqNum(uint32(c.IRS)+1),
+			checker.AckNum(uint32(790+sent)),
+			checker.Window(uint16(0xffff)),
+			checker.TCPFlags(header.TCPFlagAck),
+		),
+	)
+}
+
+func TestIncreaseWindowOnBufferResize(t *testing.T) {
+	// This test ensures that the endpoint sends an ack,
+	// after available recv buffer grows to more than 1 MSS.
+	c := context.New(t, defaultMTU)
+	defer c.Cleanup()
+
+	const rcvBuf = 65535 * 10
+	c.CreateConnected(789, 30000, rcvBuf)
+
+	// Write chunks of ~30000 bytes. It's important that two
+	// payloads make it equal or longer than MSS.
+	remain := rcvBuf
+	sent := 0
+	data := make([]byte, defaultMTU/2)
+	lastWnd := uint16(0)
+
+	for remain > len(data) {
+		c.SendPacket(data, &context.Headers{
+			SrcPort: context.TestPort,
+			DstPort: c.Port,
+			Flags:   header.TCPFlagAck,
+			SeqNum:  seqnum.Value(790 + sent),
+			AckNum:  c.IRS.Add(1),
+			RcvWnd:  30000,
+		})
+		sent += len(data)
+		remain -= len(data)
+
+		lastWnd = uint16(remain)
+		if remain > 0xffff {
+			lastWnd = 0xffff
+		}
+		checker.IPv4(t, c.GetPacket(),
+			checker.PayloadLen(header.TCPMinimumSize),
+			checker.TCP(
+				checker.DstPort(context.TestPort),
+				checker.SeqNum(uint32(c.IRS)+1),
+				checker.AckNum(uint32(790+sent)),
+				checker.Window(lastWnd),
+				checker.TCPFlags(header.TCPFlagAck),
+			),
+		)
+	}
+
+	if lastWnd == 0xffff || lastWnd == 0 {
+		t.Fatalf("expected small, non-zero window: %d", lastWnd)
+	}
+
+	// Increasing the buffer from should generate an ACK,
+	// since window grew from small value to larger equal MSS
+	c.EP.SetSockOptInt(tcpip.ReceiveBufferSizeOption, rcvBuf*2)
+
+	// After reading two packets, we surely crossed MSS. See the ack:
+	checker.IPv4(t, c.GetPacket(),
+		checker.PayloadLen(header.TCPMinimumSize),
+		checker.TCP(
+			checker.DstPort(context.TestPort),
+			checker.SeqNum(uint32(c.IRS)+1),
+			checker.AckNum(uint32(790+sent)),
+			checker.Window(uint16(0xffff)),
+			checker.TCPFlags(header.TCPFlagAck),
+		),
+	)
+}
-- 
cgit v1.2.3


From c276e4740f225068dc394a500dfdddd64af1d18a Mon Sep 17 00:00:00 2001
From: Marek Majkowski <marek@cloudflare.com>
Date: Wed, 8 Jan 2020 12:56:39 +0000
Subject: Fix #1522 - implement silly window sydrome protection on rx side

Before, each of small read()'s that raises window either from zero
or above threshold of aMSS, would generate an ACK. In a classic
silly-window-syndrome scenario, we can imagine a pessimistic case
when small read()'s generate a stream of ACKs.

This PR fixes that, essentially treating window size < aMSS as zero.
We send ACK exactly in a moment when window increases to >= aMSS
or half of receive buffer size (whichever smaller).
---
 pkg/tcpip/transport/tcp/endpoint.go | 73 +++++++++++++++++++++----------------
 pkg/tcpip/transport/tcp/tcp_test.go | 14 ++++---
 2 files changed, 51 insertions(+), 36 deletions(-)

diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index 5d42f8045..8ff125855 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -956,20 +956,11 @@ func (e *endpoint) readLocked() (buffer.View, *tcpip.Error) {
 
 	e.rcvBufUsed -= len(v)
 
-	avail := e.receiveBufferAvailableLocked()
-
-	// If the window was small before, lower than MSS, send immediate
-	// ack. Without this, the sender might be stuck  waiting for the
-	// window to grow, while we think the window is non-zero so we
-	// don't need to send acks. To avoid silly window syndrome, send
-	// ack only when the window grows above one MSS.
-	crossedMSS := avail-len(v) < int(e.amss) && avail >= int(e.amss)
-
-	// If the window was zero before this read and if the read freed up
-	// enough buffer space for the scaled window to be non-zero then notify
-	// the protocol goroutine to send a window update.
-	if (e.zeroWindow && !e.zeroReceiveWindow(e.rcv.rcvWndScale)) || crossedMSS {
-		e.zeroWindow = false
+	// If the window was small before this read and if the read
+	// freed up enough buffer space, to either fit an aMSS or half
+	// a receive buffer (whichever smaller), then notify the
+	// protocol goroutine to send a window update.
+	if e.windowCrossedACKThreshold(len(v)) == 1 {
 		e.notifyProtocolGoroutine(notifyNonZeroReceiveWindow)
 	}
 
@@ -1143,13 +1134,35 @@ func (e *endpoint) Peek(vec [][]byte) (int64, tcpip.ControlMessages, *tcpip.Erro
 	return num, tcpip.ControlMessages{}, nil
 }
 
-// zeroReceiveWindow checks if the receive window to be announced now would be
-// zero, based on the amount of available buffer and the receive window scaling.
+// windowCrossedACKThreshold checks if the receive window to be announced now would be
+// under aMSS or under half receive buffer, whichever smaller. This is useful as
+// a receive side silly window syndrome prevention mechanism. If window grows
+// to reasonable value, we should send ACK to the sender to inform the rx space is now
+// large. We also want ensure a series of small read()'s won't trigger a flood of
+// spurious tiny ACK's.
 //
-// It must be called with rcvListMu held.
-func (e *endpoint) zeroReceiveWindow(scale uint8) bool {
-	avail := e.receiveBufferAvailableLocked()
-	return (avail >> scale) == 0
+// For large receive buffers, the threshold is aMSS - once reader reads more than aMSS
+// we'll send ACK. For tiny receive buffers, the threshold is half of receive buffer size.
+// This is chosen arbitrairly.
+func (e *endpoint) windowCrossedACKThreshold(deltaBefore int) int {
+	newAvail := e.receiveBufferAvailableLocked()
+	oldAvail := newAvail - deltaBefore
+	if oldAvail < 0 {
+		oldAvail = 0
+	}
+
+	threshold := int(e.amss)
+	if threshold > e.rcvBufSize/2 {
+		threshold = e.rcvBufSize / 2
+	}
+
+	switch {
+	case oldAvail < threshold && newAvail >= threshold:
+		return 1
+	case oldAvail >= threshold && newAvail < threshold:
+		return -1
+	}
+	return 0
 }
 
 // SetSockOptInt sets a socket option.
@@ -1194,11 +1207,11 @@ func (e *endpoint) SetSockOptInt(opt tcpip.SockOpt, v int) *tcpip.Error {
 
 		e.rcvAutoParams.disabled = true
 
-		// Immediatelly send ACK in two cases: when the buffer
-		// grows so that it leaves zero-window state, when the
-		// buffer grows from small < MSS to >= MSS.
-		if (e.zeroWindow && !e.zeroReceiveWindow(scale)) || (availBefore < int(e.amss) && availAfter >= int(e.amss)) {
-			e.zeroWindow = false
+		// Immediatelly send an ACK to uncork the sender silly
+		// window syndrome prevetion, when our available space
+		// grows above aMSS or half receive buffer, whichever
+		// smaller.
+		if e.windowCrossedACKThreshold(availAfter-availBefore) == 1 {
 			mask |= notifyNonZeroReceiveWindow
 		}
 		e.rcvListMu.Unlock()
@@ -2239,13 +2252,11 @@ func (e *endpoint) readyToRead(s *segment) {
 	if s != nil {
 		s.incRef()
 		e.rcvBufUsed += s.data.Size()
-		// Check if the receive window is now closed. If so make sure
-		// we set the zero window before we deliver the segment to ensure
-		// that a subsequent read of the segment will correctly trigger
-		// a non-zero notification.
-		if e.zeroReceiveWindow(e.rcv.rcvWndScale) {
+		// Increase counter if the receive window falls down
+		// below MSS or half receive buffer size, whichever
+		// smaller.
+		if e.windowCrossedACKThreshold(-s.data.Size()) == -1 {
 			e.stats.ReceiveErrors.ZeroRcvWindowState.Increment()
-			e.zeroWindow = true
 		}
 		e.rcvList.PushBack(s)
 	} else {
diff --git a/pkg/tcpip/transport/tcp/tcp_test.go b/pkg/tcpip/transport/tcp/tcp_test.go
index a05365c6a..4c2e458e3 100644
--- a/pkg/tcpip/transport/tcp/tcp_test.go
+++ b/pkg/tcpip/transport/tcp/tcp_test.go
@@ -2091,10 +2091,14 @@ func TestZeroScaledWindowReceive(t *testing.T) {
 		)
 	}
 
-	// Read some data. An ack should be sent in response to that.
-	v, _, err := c.EP.Read(nil)
-	if err != nil {
-		t.Fatalf("Read failed: %v", err)
+	// Read at least 1MSS of data. An ack should be sent in response to that.
+	sz := 0
+	for sz < defaultMTU {
+		v, _, err := c.EP.Read(nil)
+		if err != nil {
+			t.Fatalf("Read failed: %v", err)
+		}
+		sz += len(v)
 	}
 
 	checker.IPv4(t, c.GetPacket(),
@@ -2103,7 +2107,7 @@ func TestZeroScaledWindowReceive(t *testing.T) {
 			checker.DstPort(context.TestPort),
 			checker.SeqNum(uint32(c.IRS)+1),
 			checker.AckNum(uint32(790+sent)),
-			checker.Window(uint16(len(v)>>ws)),
+			checker.Window(uint16(sz>>ws)),
 			checker.TCPFlags(header.TCPFlagAck),
 		),
 	)
-- 
cgit v1.2.3


From 9df018767cdfee5d837746b6dce6dafd9b9fcfce Mon Sep 17 00:00:00 2001
From: Tamir Duberstein <tamird@google.com>
Date: Wed, 8 Jan 2020 10:10:57 -0800
Subject: Remove redundant function argument

PacketLooping is already a member on the passed Route.

PiperOrigin-RevId: 288721500
---
 pkg/tcpip/network/arp/arp.go    |  6 +++---
 pkg/tcpip/network/ip_test.go    |  4 ++--
 pkg/tcpip/network/ipv4/ipv4.go  | 18 +++++++++---------
 pkg/tcpip/network/ipv6/ipv6.go  | 14 +++++++-------
 pkg/tcpip/stack/registration.go |  6 +++---
 pkg/tcpip/stack/route.go        |  6 +++---
 pkg/tcpip/stack/stack_test.go   | 10 +++++-----
 7 files changed, 32 insertions(+), 32 deletions(-)

diff --git a/pkg/tcpip/network/arp/arp.go b/pkg/tcpip/network/arp/arp.go
index da8482509..42cacb8a6 100644
--- a/pkg/tcpip/network/arp/arp.go
+++ b/pkg/tcpip/network/arp/arp.go
@@ -79,16 +79,16 @@ func (e *endpoint) MaxHeaderLength() uint16 {
 
 func (e *endpoint) Close() {}
 
-func (e *endpoint) WritePacket(*stack.Route, *stack.GSO, stack.NetworkHeaderParams, stack.PacketLooping, tcpip.PacketBuffer) *tcpip.Error {
+func (e *endpoint) WritePacket(*stack.Route, *stack.GSO, stack.NetworkHeaderParams, tcpip.PacketBuffer) *tcpip.Error {
 	return tcpip.ErrNotSupported
 }
 
 // WritePackets implements stack.NetworkEndpoint.WritePackets.
-func (e *endpoint) WritePackets(*stack.Route, *stack.GSO, []tcpip.PacketBuffer, stack.NetworkHeaderParams, stack.PacketLooping) (int, *tcpip.Error) {
+func (e *endpoint) WritePackets(*stack.Route, *stack.GSO, []tcpip.PacketBuffer, stack.NetworkHeaderParams) (int, *tcpip.Error) {
 	return 0, tcpip.ErrNotSupported
 }
 
-func (e *endpoint) WriteHeaderIncludedPacket(r *stack.Route, loop stack.PacketLooping, pkt tcpip.PacketBuffer) *tcpip.Error {
+func (e *endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt tcpip.PacketBuffer) *tcpip.Error {
 	return tcpip.ErrNotSupported
 }
 
diff --git a/pkg/tcpip/network/ip_test.go b/pkg/tcpip/network/ip_test.go
index 4144a7837..f1bc33adf 100644
--- a/pkg/tcpip/network/ip_test.go
+++ b/pkg/tcpip/network/ip_test.go
@@ -239,7 +239,7 @@ func TestIPv4Send(t *testing.T) {
 	if err != nil {
 		t.Fatalf("could not find route: %v", err)
 	}
-	if err := ep.WritePacket(&r, nil /* gso */, stack.NetworkHeaderParams{Protocol: 123, TTL: 123, TOS: stack.DefaultTOS}, stack.PacketOut, tcpip.PacketBuffer{
+	if err := ep.WritePacket(&r, nil /* gso */, stack.NetworkHeaderParams{Protocol: 123, TTL: 123, TOS: stack.DefaultTOS}, tcpip.PacketBuffer{
 		Header: hdr,
 		Data:   payload.ToVectorisedView(),
 	}); err != nil {
@@ -480,7 +480,7 @@ func TestIPv6Send(t *testing.T) {
 	if err != nil {
 		t.Fatalf("could not find route: %v", err)
 	}
-	if err := ep.WritePacket(&r, nil /* gso */, stack.NetworkHeaderParams{Protocol: 123, TTL: 123, TOS: stack.DefaultTOS}, stack.PacketOut, tcpip.PacketBuffer{
+	if err := ep.WritePacket(&r, nil /* gso */, stack.NetworkHeaderParams{Protocol: 123, TTL: 123, TOS: stack.DefaultTOS}, tcpip.PacketBuffer{
 		Header: hdr,
 		Data:   payload.ToVectorisedView(),
 	}); err != nil {
diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go
index e645cf62c..4ee3d5b45 100644
--- a/pkg/tcpip/network/ipv4/ipv4.go
+++ b/pkg/tcpip/network/ipv4/ipv4.go
@@ -238,11 +238,11 @@ func (e *endpoint) addIPHeader(r *stack.Route, hdr *buffer.Prependable, payloadS
 }
 
 // WritePacket writes a packet to the given destination address and protocol.
-func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.NetworkHeaderParams, loop stack.PacketLooping, pkt tcpip.PacketBuffer) *tcpip.Error {
+func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.NetworkHeaderParams, pkt tcpip.PacketBuffer) *tcpip.Error {
 	ip := e.addIPHeader(r, &pkt.Header, pkt.Data.Size(), params)
 	pkt.NetworkHeader = buffer.View(ip)
 
-	if loop&stack.PacketLoop != 0 {
+	if r.Loop&stack.PacketLoop != 0 {
 		// The inbound path expects the network header to still be in
 		// the PacketBuffer's Data field.
 		views := make([]buffer.View, 1, 1+len(pkt.Data.Views()))
@@ -256,7 +256,7 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.Netw
 
 		loopedR.Release()
 	}
-	if loop&stack.PacketOut == 0 {
+	if r.Loop&stack.PacketOut == 0 {
 		return nil
 	}
 	if pkt.Header.UsedLength()+pkt.Data.Size() > int(e.linkEP.MTU()) && (gso == nil || gso.Type == stack.GSONone) {
@@ -270,11 +270,11 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.Netw
 }
 
 // WritePackets implements stack.NetworkEndpoint.WritePackets.
-func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts []tcpip.PacketBuffer, params stack.NetworkHeaderParams, loop stack.PacketLooping) (int, *tcpip.Error) {
-	if loop&stack.PacketLoop != 0 {
+func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts []tcpip.PacketBuffer, params stack.NetworkHeaderParams) (int, *tcpip.Error) {
+	if r.Loop&stack.PacketLoop != 0 {
 		panic("multiple packets in local loop")
 	}
-	if loop&stack.PacketOut == 0 {
+	if r.Loop&stack.PacketOut == 0 {
 		return len(pkts), nil
 	}
 
@@ -289,7 +289,7 @@ func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts []tcpip.Pac
 
 // WriteHeaderIncludedPacket writes a packet already containing a network
 // header through the given route.
-func (e *endpoint) WriteHeaderIncludedPacket(r *stack.Route, loop stack.PacketLooping, pkt tcpip.PacketBuffer) *tcpip.Error {
+func (e *endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt tcpip.PacketBuffer) *tcpip.Error {
 	// The packet already has an IP header, but there are a few required
 	// checks.
 	ip := header.IPv4(pkt.Data.First())
@@ -324,10 +324,10 @@ func (e *endpoint) WriteHeaderIncludedPacket(r *stack.Route, loop stack.PacketLo
 	ip.SetChecksum(0)
 	ip.SetChecksum(^ip.CalculateChecksum())
 
-	if loop&stack.PacketLoop != 0 {
+	if r.Loop&stack.PacketLoop != 0 {
 		e.HandlePacket(r, pkt.Clone())
 	}
-	if loop&stack.PacketOut == 0 {
+	if r.Loop&stack.PacketOut == 0 {
 		return nil
 	}
 
diff --git a/pkg/tcpip/network/ipv6/ipv6.go b/pkg/tcpip/network/ipv6/ipv6.go
index e13f1fabf..58c3c79b9 100644
--- a/pkg/tcpip/network/ipv6/ipv6.go
+++ b/pkg/tcpip/network/ipv6/ipv6.go
@@ -112,11 +112,11 @@ func (e *endpoint) addIPHeader(r *stack.Route, hdr *buffer.Prependable, payloadS
 }
 
 // WritePacket writes a packet to the given destination address and protocol.
-func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.NetworkHeaderParams, loop stack.PacketLooping, pkt tcpip.PacketBuffer) *tcpip.Error {
+func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.NetworkHeaderParams, pkt tcpip.PacketBuffer) *tcpip.Error {
 	ip := e.addIPHeader(r, &pkt.Header, pkt.Data.Size(), params)
 	pkt.NetworkHeader = buffer.View(ip)
 
-	if loop&stack.PacketLoop != 0 {
+	if r.Loop&stack.PacketLoop != 0 {
 		// The inbound path expects the network header to still be in
 		// the PacketBuffer's Data field.
 		views := make([]buffer.View, 1, 1+len(pkt.Data.Views()))
@@ -130,7 +130,7 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.Netw
 
 		loopedR.Release()
 	}
-	if loop&stack.PacketOut == 0 {
+	if r.Loop&stack.PacketOut == 0 {
 		return nil
 	}
 
@@ -139,11 +139,11 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.Netw
 }
 
 // WritePackets implements stack.LinkEndpoint.WritePackets.
-func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts []tcpip.PacketBuffer, params stack.NetworkHeaderParams, loop stack.PacketLooping) (int, *tcpip.Error) {
-	if loop&stack.PacketLoop != 0 {
+func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts []tcpip.PacketBuffer, params stack.NetworkHeaderParams) (int, *tcpip.Error) {
+	if r.Loop&stack.PacketLoop != 0 {
 		panic("not implemented")
 	}
-	if loop&stack.PacketOut == 0 {
+	if r.Loop&stack.PacketOut == 0 {
 		return len(pkts), nil
 	}
 
@@ -161,7 +161,7 @@ func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts []tcpip.Pac
 
 // WriteHeaderIncludedPacker implements stack.NetworkEndpoint. It is not yet
 // supported by IPv6.
-func (*endpoint) WriteHeaderIncludedPacket(r *stack.Route, loop stack.PacketLooping, pkt tcpip.PacketBuffer) *tcpip.Error {
+func (*endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt tcpip.PacketBuffer) *tcpip.Error {
 	// TODO(b/146666412): Support IPv6 header-included packets.
 	return tcpip.ErrNotSupported
 }
diff --git a/pkg/tcpip/stack/registration.go b/pkg/tcpip/stack/registration.go
index 61fd46d66..2b8751d49 100644
--- a/pkg/tcpip/stack/registration.go
+++ b/pkg/tcpip/stack/registration.go
@@ -234,15 +234,15 @@ type NetworkEndpoint interface {
 	// WritePacket writes a packet to the given destination address and
 	// protocol. It sets pkt.NetworkHeader. pkt.TransportHeader must have
 	// already been set.
-	WritePacket(r *Route, gso *GSO, params NetworkHeaderParams, loop PacketLooping, pkt tcpip.PacketBuffer) *tcpip.Error
+	WritePacket(r *Route, gso *GSO, params NetworkHeaderParams, pkt tcpip.PacketBuffer) *tcpip.Error
 
 	// WritePackets writes packets to the given destination address and
 	// protocol. pkts must not be zero length.
-	WritePackets(r *Route, gso *GSO, pkts []tcpip.PacketBuffer, params NetworkHeaderParams, loop PacketLooping) (int, *tcpip.Error)
+	WritePackets(r *Route, gso *GSO, pkts []tcpip.PacketBuffer, params NetworkHeaderParams) (int, *tcpip.Error)
 
 	// WriteHeaderIncludedPacket writes a packet that includes a network
 	// header to the given destination address.
-	WriteHeaderIncludedPacket(r *Route, loop PacketLooping, pkt tcpip.PacketBuffer) *tcpip.Error
+	WriteHeaderIncludedPacket(r *Route, pkt tcpip.PacketBuffer) *tcpip.Error
 
 	// ID returns the network protocol endpoint ID.
 	ID() *NetworkEndpointID
diff --git a/pkg/tcpip/stack/route.go b/pkg/tcpip/stack/route.go
index 34307ae07..517f4b941 100644
--- a/pkg/tcpip/stack/route.go
+++ b/pkg/tcpip/stack/route.go
@@ -158,7 +158,7 @@ func (r *Route) WritePacket(gso *GSO, params NetworkHeaderParams, pkt tcpip.Pack
 		return tcpip.ErrInvalidEndpointState
 	}
 
-	err := r.ref.ep.WritePacket(r, gso, params, r.Loop, pkt)
+	err := r.ref.ep.WritePacket(r, gso, params, pkt)
 	if err != nil {
 		r.Stats().IP.OutgoingPacketErrors.Increment()
 	} else {
@@ -174,7 +174,7 @@ func (r *Route) WritePackets(gso *GSO, pkts []tcpip.PacketBuffer, params Network
 		return 0, tcpip.ErrInvalidEndpointState
 	}
 
-	n, err := r.ref.ep.WritePackets(r, gso, pkts, params, r.Loop)
+	n, err := r.ref.ep.WritePackets(r, gso, pkts, params)
 	if err != nil {
 		r.Stats().IP.OutgoingPacketErrors.IncrementBy(uint64(len(pkts) - n))
 	}
@@ -195,7 +195,7 @@ func (r *Route) WriteHeaderIncludedPacket(pkt tcpip.PacketBuffer) *tcpip.Error {
 		return tcpip.ErrInvalidEndpointState
 	}
 
-	if err := r.ref.ep.WriteHeaderIncludedPacket(r, r.Loop, pkt); err != nil {
+	if err := r.ref.ep.WriteHeaderIncludedPacket(r, pkt); err != nil {
 		r.Stats().IP.OutgoingPacketErrors.Increment()
 		return err
 	}
diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go
index bf057745e..33f20579f 100644
--- a/pkg/tcpip/stack/stack_test.go
+++ b/pkg/tcpip/stack/stack_test.go
@@ -124,7 +124,7 @@ func (f *fakeNetworkEndpoint) Capabilities() stack.LinkEndpointCapabilities {
 	return f.ep.Capabilities()
 }
 
-func (f *fakeNetworkEndpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.NetworkHeaderParams, loop stack.PacketLooping, pkt tcpip.PacketBuffer) *tcpip.Error {
+func (f *fakeNetworkEndpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.NetworkHeaderParams, pkt tcpip.PacketBuffer) *tcpip.Error {
 	// Increment the sent packet count in the protocol descriptor.
 	f.proto.sendPacketCount[int(r.RemoteAddress[0])%len(f.proto.sendPacketCount)]++
 
@@ -135,7 +135,7 @@ func (f *fakeNetworkEndpoint) WritePacket(r *stack.Route, gso *stack.GSO, params
 	b[1] = f.id.LocalAddress[0]
 	b[2] = byte(params.Protocol)
 
-	if loop&stack.PacketLoop != 0 {
+	if r.Loop&stack.PacketLoop != 0 {
 		views := make([]buffer.View, 1, 1+len(pkt.Data.Views()))
 		views[0] = pkt.Header.View()
 		views = append(views, pkt.Data.Views()...)
@@ -143,7 +143,7 @@ func (f *fakeNetworkEndpoint) WritePacket(r *stack.Route, gso *stack.GSO, params
 			Data: buffer.NewVectorisedView(len(views[0])+pkt.Data.Size(), views),
 		})
 	}
-	if loop&stack.PacketOut == 0 {
+	if r.Loop&stack.PacketOut == 0 {
 		return nil
 	}
 
@@ -151,11 +151,11 @@ func (f *fakeNetworkEndpoint) WritePacket(r *stack.Route, gso *stack.GSO, params
 }
 
 // WritePackets implements stack.LinkEndpoint.WritePackets.
-func (f *fakeNetworkEndpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts []tcpip.PacketBuffer, params stack.NetworkHeaderParams, loop stack.PacketLooping) (int, *tcpip.Error) {
+func (f *fakeNetworkEndpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts []tcpip.PacketBuffer, params stack.NetworkHeaderParams) (int, *tcpip.Error) {
 	panic("not implemented")
 }
 
-func (*fakeNetworkEndpoint) WriteHeaderIncludedPacket(r *stack.Route, loop stack.PacketLooping, pkt tcpip.PacketBuffer) *tcpip.Error {
+func (*fakeNetworkEndpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt tcpip.PacketBuffer) *tcpip.Error {
 	return tcpip.ErrNotSupported
 }
 
-- 
cgit v1.2.3


From db376e13924be59182ed4df95762328febf26298 Mon Sep 17 00:00:00 2001
From: Fabricio Voznika <fvoznika@google.com>
Date: Wed, 8 Jan 2020 10:30:50 -0800
Subject: Make /proc/[pid] offset start at TGID_OFFSET

Updates #1195

PiperOrigin-RevId: 288725745
---
 pkg/sentry/fsimpl/proc/tasks.go      | 102 ++++++++++++++++++------
 pkg/sentry/fsimpl/proc/tasks_test.go | 147 ++++++++++++++++++++++++++++++++++-
 2 files changed, 223 insertions(+), 26 deletions(-)

diff --git a/pkg/sentry/fsimpl/proc/tasks.go b/pkg/sentry/fsimpl/proc/tasks.go
index 50b2a832f..d8f92d52f 100644
--- a/pkg/sentry/fsimpl/proc/tasks.go
+++ b/pkg/sentry/fsimpl/proc/tasks.go
@@ -27,7 +27,11 @@ import (
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
-const defaultPermission = 0444
+const (
+	defaultPermission = 0444
+	selfName          = "self"
+	threadSelfName    = "thread-self"
+)
 
 // InoGenerator generates unique inode numbers for a given filesystem.
 type InoGenerator interface {
@@ -45,6 +49,11 @@ type tasksInode struct {
 
 	inoGen InoGenerator
 	pidns  *kernel.PIDNamespace
+
+	// '/proc/self' and '/proc/thread-self' have custom directory offsets in
+	// Linux. So handle them outside of OrderedChildren.
+	selfSymlink       *vfs.Dentry
+	threadSelfSymlink *vfs.Dentry
 }
 
 var _ kernfs.Inode = (*tasksInode)(nil)
@@ -54,20 +63,20 @@ func newTasksInode(inoGen InoGenerator, k *kernel.Kernel, pidns *kernel.PIDNames
 	contents := map[string]*kernfs.Dentry{
 		//"cpuinfo":     newCPUInfo(ctx, msrc),
 		//"filesystems": seqfile.NewSeqFileInode(ctx, &filesystemsData{}, msrc),
-		"loadavg":     newDentry(root, inoGen.NextIno(), defaultPermission, &loadavgData{}),
-		"meminfo":     newDentry(root, inoGen.NextIno(), defaultPermission, &meminfoData{k: k}),
-		"mounts":      kernfs.NewStaticSymlink(root, inoGen.NextIno(), defaultPermission, "self/mounts"),
-		"self":        newSelfSymlink(root, inoGen.NextIno(), defaultPermission, pidns),
-		"stat":        newDentry(root, inoGen.NextIno(), defaultPermission, &statData{k: k}),
-		"thread-self": newThreadSelfSymlink(root, inoGen.NextIno(), defaultPermission, pidns),
+		"loadavg": newDentry(root, inoGen.NextIno(), defaultPermission, &loadavgData{}),
+		"meminfo": newDentry(root, inoGen.NextIno(), defaultPermission, &meminfoData{k: k}),
+		"mounts":  kernfs.NewStaticSymlink(root, inoGen.NextIno(), defaultPermission, "self/mounts"),
+		"stat":    newDentry(root, inoGen.NextIno(), defaultPermission, &statData{k: k}),
 		//"uptime":      newUptime(ctx, msrc),
 		//"version": newVersionData(root, inoGen.NextIno(), k),
 		"version": newDentry(root, inoGen.NextIno(), defaultPermission, &versionData{k: k}),
 	}
 
 	inode := &tasksInode{
-		pidns:  pidns,
-		inoGen: inoGen,
+		pidns:             pidns,
+		inoGen:            inoGen,
+		selfSymlink:       newSelfSymlink(root, inoGen.NextIno(), 0444, pidns).VFSDentry(),
+		threadSelfSymlink: newThreadSelfSymlink(root, inoGen.NextIno(), 0444, pidns).VFSDentry(),
 	}
 	inode.InodeAttrs.Init(root, inoGen.NextIno(), linux.ModeDirectory|0555)
 
@@ -86,6 +95,13 @@ func (i *tasksInode) Lookup(ctx context.Context, name string) (*vfs.Dentry, erro
 	// Try to lookup a corresponding task.
 	tid, err := strconv.ParseUint(name, 10, 64)
 	if err != nil {
+		// If it failed to parse, check if it's one of the special handled files.
+		switch name {
+		case selfName:
+			return i.selfSymlink, nil
+		case threadSelfName:
+			return i.threadSelfSymlink, nil
+		}
 		return nil, syserror.ENOENT
 	}
 
@@ -104,41 +120,81 @@ func (i *tasksInode) Valid(ctx context.Context) bool {
 }
 
 // IterDirents implements kernfs.inodeDynamicLookup.
-//
-// TODO(gvisor.dev/issue/1195): Use tgid N offset = TGID_OFFSET + N.
-func (i *tasksInode) IterDirents(ctx context.Context, cb vfs.IterDirentsCallback, offset, relOffset int64) (int64, error) {
-	var tids []int
+func (i *tasksInode) IterDirents(ctx context.Context, cb vfs.IterDirentsCallback, offset, _ int64) (int64, error) {
+	// fs/proc/internal.h: #define FIRST_PROCESS_ENTRY 256
+	const FIRST_PROCESS_ENTRY = 256
+
+	// Use maxTaskID to shortcut searches that will result in 0 entries.
+	const maxTaskID = kernel.TasksLimit + 1
+	if offset >= maxTaskID {
+		return offset, nil
+	}
+
+	// According to Linux (fs/proc/base.c:proc_pid_readdir()), process directories
+	// start at offset FIRST_PROCESS_ENTRY with '/proc/self', followed by
+	// '/proc/thread-self' and then '/proc/[pid]'.
+	if offset < FIRST_PROCESS_ENTRY {
+		offset = FIRST_PROCESS_ENTRY
+	}
+
+	if offset == FIRST_PROCESS_ENTRY {
+		dirent := vfs.Dirent{
+			Name:    selfName,
+			Type:    linux.DT_LNK,
+			Ino:     i.inoGen.NextIno(),
+			NextOff: offset + 1,
+		}
+		if !cb.Handle(dirent) {
+			return offset, nil
+		}
+		offset++
+	}
+	if offset == FIRST_PROCESS_ENTRY+1 {
+		dirent := vfs.Dirent{
+			Name:    threadSelfName,
+			Type:    linux.DT_LNK,
+			Ino:     i.inoGen.NextIno(),
+			NextOff: offset + 1,
+		}
+		if !cb.Handle(dirent) {
+			return offset, nil
+		}
+		offset++
+	}
 
-	// Collect all tasks. Per linux we only include it in directory listings if
-	// it's the leader. But for whatever crazy reason, you can still walk to the
-	// given node.
+	// Collect all tasks that TGIDs are greater than the offset specified. Per
+	// Linux we only include in directory listings if it's the leader. But for
+	// whatever crazy reason, you can still walk to the given node.
+	var tids []int
+	startTid := offset - FIRST_PROCESS_ENTRY - 2
 	for _, tg := range i.pidns.ThreadGroups() {
+		tid := i.pidns.IDOfThreadGroup(tg)
+		if int64(tid) < startTid {
+			continue
+		}
 		if leader := tg.Leader(); leader != nil {
-			tids = append(tids, int(i.pidns.IDOfThreadGroup(tg)))
+			tids = append(tids, int(tid))
 		}
 	}
 
 	if len(tids) == 0 {
 		return offset, nil
 	}
-	if relOffset >= int64(len(tids)) {
-		return offset, nil
-	}
 
 	sort.Ints(tids)
-	for _, tid := range tids[relOffset:] {
+	for _, tid := range tids {
 		dirent := vfs.Dirent{
 			Name:    strconv.FormatUint(uint64(tid), 10),
 			Type:    linux.DT_DIR,
 			Ino:     i.inoGen.NextIno(),
-			NextOff: offset + 1,
+			NextOff: FIRST_PROCESS_ENTRY + 2 + int64(tid) + 1,
 		}
 		if !cb.Handle(dirent) {
 			return offset, nil
 		}
 		offset++
 	}
-	return offset, nil
+	return maxTaskID, nil
 }
 
 // Open implements kernfs.Inode.
diff --git a/pkg/sentry/fsimpl/proc/tasks_test.go b/pkg/sentry/fsimpl/proc/tasks_test.go
index 2560fcef9..ca8c87ec2 100644
--- a/pkg/sentry/fsimpl/proc/tasks_test.go
+++ b/pkg/sentry/fsimpl/proc/tasks_test.go
@@ -16,6 +16,7 @@ package proc
 
 import (
 	"fmt"
+	"math"
 	"path"
 	"strconv"
 	"testing"
@@ -30,6 +31,18 @@ import (
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
+var (
+	// Next offset 256 by convention. Adds 1 for the next offset.
+	selfLink       = vfs.Dirent{Type: linux.DT_LNK, NextOff: 256 + 0 + 1}
+	threadSelfLink = vfs.Dirent{Type: linux.DT_LNK, NextOff: 256 + 1 + 1}
+
+	// /proc/[pid] next offset starts at 256+2 (files above), then adds the
+	// PID, and adds 1 for the next offset.
+	proc1 = vfs.Dirent{Type: linux.DT_DIR, NextOff: 258 + 1 + 1}
+	proc2 = vfs.Dirent{Type: linux.DT_DIR, NextOff: 258 + 2 + 1}
+	proc3 = vfs.Dirent{Type: linux.DT_DIR, NextOff: 258 + 3 + 1}
+)
+
 type testIterDirentsCallback struct {
 	dirents []vfs.Dirent
 }
@@ -59,9 +72,9 @@ func checkTasksStaticFiles(gots []vfs.Dirent) ([]vfs.Dirent, error) {
 		"loadavg":     {Type: linux.DT_REG},
 		"meminfo":     {Type: linux.DT_REG},
 		"mounts":      {Type: linux.DT_LNK},
-		"self":        {Type: linux.DT_LNK},
+		"self":        selfLink,
 		"stat":        {Type: linux.DT_REG},
-		"thread-self": {Type: linux.DT_LNK},
+		"thread-self": threadSelfLink,
 		"version":     {Type: linux.DT_REG},
 	}
 	return checkFiles(gots, wants)
@@ -93,6 +106,9 @@ func checkFiles(gots []vfs.Dirent, wants map[string]vfs.Dirent) ([]vfs.Dirent, e
 		if want.Type != got.Type {
 			return gots, fmt.Errorf("wrong file type, want: %v, got: %v: %+v", want.Type, got.Type, got)
 		}
+		if want.NextOff != 0 && want.NextOff != got.NextOff {
+			return gots, fmt.Errorf("wrong dirent offset, want: %v, got: %v: %+v", want.NextOff, got.NextOff, got)
+		}
 
 		delete(wants, got.Name)
 		gots = append(gots[0:i], gots[i+1:]...)
@@ -154,7 +170,7 @@ func TestTasksEmpty(t *testing.T) {
 		t.Error(err.Error())
 	}
 	if len(cb.dirents) != 0 {
-		t.Error("found more files than expected: %+v", cb.dirents)
+		t.Errorf("found more files than expected: %+v", cb.dirents)
 	}
 }
 
@@ -216,6 +232,11 @@ func TestTasks(t *testing.T) {
 		if !found {
 			t.Errorf("Additional task ID %d listed: %v", pid, tasks)
 		}
+		// Next offset starts at 256+2 ('self' and 'thread-self'), then adds the
+		// PID, and adds 1 for the next offset.
+		if want := int64(256 + 2 + pid + 1); d.NextOff != want {
+			t.Errorf("Wrong dirent offset want: %d got: %d: %+v", want, d.NextOff, d)
+		}
 	}
 
 	// Test lookup.
@@ -246,6 +267,126 @@ func TestTasks(t *testing.T) {
 	}
 }
 
+func TestTasksOffset(t *testing.T) {
+	ctx, vfsObj, root, err := setup()
+	if err != nil {
+		t.Fatalf("Setup failed: %v", err)
+	}
+	defer root.DecRef()
+
+	k := kernel.KernelFromContext(ctx)
+	for i := 0; i < 3; i++ {
+		tc := k.NewThreadGroup(nil, k.RootPIDNamespace(), kernel.NewSignalHandlers(), linux.SIGCHLD, k.GlobalInit().Limits())
+		if _, err := createTask(ctx, fmt.Sprintf("name-%d", i), tc); err != nil {
+			t.Fatalf("CreateTask(): %v", err)
+		}
+	}
+
+	for _, tc := range []struct {
+		name   string
+		offset int64
+		wants  map[string]vfs.Dirent
+	}{
+		{
+			name:   "small offset",
+			offset: 100,
+			wants: map[string]vfs.Dirent{
+				"self":        selfLink,
+				"thread-self": threadSelfLink,
+				"1":           proc1,
+				"2":           proc2,
+				"3":           proc3,
+			},
+		},
+		{
+			name:   "offset at start",
+			offset: 256,
+			wants: map[string]vfs.Dirent{
+				"self":        selfLink,
+				"thread-self": threadSelfLink,
+				"1":           proc1,
+				"2":           proc2,
+				"3":           proc3,
+			},
+		},
+		{
+			name:   "skip /proc/self",
+			offset: 257,
+			wants: map[string]vfs.Dirent{
+				"thread-self": threadSelfLink,
+				"1":           proc1,
+				"2":           proc2,
+				"3":           proc3,
+			},
+		},
+		{
+			name:   "skip symlinks",
+			offset: 258,
+			wants: map[string]vfs.Dirent{
+				"1": proc1,
+				"2": proc2,
+				"3": proc3,
+			},
+		},
+		{
+			name:   "skip first process",
+			offset: 260,
+			wants: map[string]vfs.Dirent{
+				"2": proc2,
+				"3": proc3,
+			},
+		},
+		{
+			name:   "last process",
+			offset: 261,
+			wants: map[string]vfs.Dirent{
+				"3": proc3,
+			},
+		},
+		{
+			name:   "after last",
+			offset: 262,
+			wants:  nil,
+		},
+		{
+			name:   "TaskLimit+1",
+			offset: kernel.TasksLimit + 1,
+			wants:  nil,
+		},
+		{
+			name:   "max",
+			offset: math.MaxInt64,
+			wants:  nil,
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			fd, err := vfsObj.OpenAt(
+				ctx,
+				auth.CredentialsFromContext(ctx),
+				&vfs.PathOperation{Root: root, Start: root, Path: fspath.Parse("/")},
+				&vfs.OpenOptions{},
+			)
+			if err != nil {
+				t.Fatalf("vfsfs.OpenAt(/) failed: %v", err)
+			}
+			if _, err := fd.Impl().Seek(ctx, tc.offset, linux.SEEK_SET); err != nil {
+				t.Fatalf("Seek(%d, SEEK_SET): %v", tc.offset, err)
+			}
+
+			cb := testIterDirentsCallback{}
+			if err := fd.Impl().IterDirents(ctx, &cb); err != nil {
+				t.Fatalf("IterDirents(): %v", err)
+			}
+			if cb.dirents, err = checkFiles(cb.dirents, tc.wants); err != nil {
+				t.Error(err.Error())
+			}
+			if len(cb.dirents) != 0 {
+				t.Errorf("found more files than expected: %+v", cb.dirents)
+			}
+		})
+	}
+}
+
 func TestTask(t *testing.T) {
 	ctx, vfsObj, root, err := setup()
 	if err != nil {
-- 
cgit v1.2.3


From d01240d871c8737989b1af27c137f6ae40bc6d37 Mon Sep 17 00:00:00 2001
From: Tamir Duberstein <tamird@google.com>
Date: Wed, 8 Jan 2020 13:52:56 -0800
Subject: Take addresses as const

PiperOrigin-RevId: 288767927
---
 test/syscalls/linux/ip_socket_test_util.cc | 10 +++++-----
 test/syscalls/linux/ip_socket_test_util.h  |  6 +++---
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/test/syscalls/linux/ip_socket_test_util.cc b/test/syscalls/linux/ip_socket_test_util.cc
index 8398fc95f..6b472eb2f 100644
--- a/test/syscalls/linux/ip_socket_test_util.cc
+++ b/test/syscalls/linux/ip_socket_test_util.cc
@@ -187,24 +187,24 @@ PosixErrorOr<int> IfAddrHelper::GetIndex(std::string name) {
   return InterfaceIndex(name);
 }
 
-std::string GetAddr4Str(in_addr* a) {
+std::string GetAddr4Str(const in_addr* a) {
   char str[INET_ADDRSTRLEN];
   inet_ntop(AF_INET, a, str, sizeof(str));
   return std::string(str);
 }
 
-std::string GetAddr6Str(in6_addr* a) {
+std::string GetAddr6Str(const in6_addr* a) {
   char str[INET6_ADDRSTRLEN];
   inet_ntop(AF_INET6, a, str, sizeof(str));
   return std::string(str);
 }
 
-std::string GetAddrStr(sockaddr* a) {
+std::string GetAddrStr(const sockaddr* a) {
   if (a->sa_family == AF_INET) {
-    auto src = &(reinterpret_cast<sockaddr_in*>(a)->sin_addr);
+    auto src = &(reinterpret_cast<const sockaddr_in*>(a)->sin_addr);
     return GetAddr4Str(src);
   } else if (a->sa_family == AF_INET6) {
-    auto src = &(reinterpret_cast<sockaddr_in6*>(a)->sin6_addr);
+    auto src = &(reinterpret_cast<const sockaddr_in6*>(a)->sin6_addr);
     return GetAddr6Str(src);
   }
   return std::string("<invalid>");
diff --git a/test/syscalls/linux/ip_socket_test_util.h b/test/syscalls/linux/ip_socket_test_util.h
index 9cb4566db..0f58e0f77 100644
--- a/test/syscalls/linux/ip_socket_test_util.h
+++ b/test/syscalls/linux/ip_socket_test_util.h
@@ -105,14 +105,14 @@ class IfAddrHelper {
 };
 
 // GetAddr4Str returns the given IPv4 network address structure as a string.
-std::string GetAddr4Str(in_addr* a);
+std::string GetAddr4Str(const in_addr* a);
 
 // GetAddr6Str returns the given IPv6 network address structure as a string.
-std::string GetAddr6Str(in6_addr* a);
+std::string GetAddr6Str(const in6_addr* a);
 
 // GetAddrStr returns the given IPv4 or IPv6 network address structure as a
 // string.
-std::string GetAddrStr(sockaddr* a);
+std::string GetAddrStr(const sockaddr* a);
 
 }  // namespace testing
 }  // namespace gvisor
-- 
cgit v1.2.3


From a271bccfc61390be64ca0175b8fc7d20e66d05b6 Mon Sep 17 00:00:00 2001
From: Tamir Duberstein <tamird@google.com>
Date: Wed, 8 Jan 2020 14:16:38 -0800
Subject: Rename tcpip.SockOpt{,Int}

PiperOrigin-RevId: 288772878
---
 pkg/sentry/socket/netstack/netstack.go   |  4 ++--
 pkg/sentry/socket/unix/transport/unix.go |  8 ++++----
 pkg/tcpip/stack/transport_test.go        |  4 ++--
 pkg/tcpip/tcpip.go                       | 10 +++++-----
 pkg/tcpip/transport/icmp/endpoint.go     |  4 ++--
 pkg/tcpip/transport/packet/endpoint.go   |  4 ++--
 pkg/tcpip/transport/raw/endpoint.go      |  4 ++--
 pkg/tcpip/transport/tcp/endpoint.go      |  4 ++--
 pkg/tcpip/transport/udp/endpoint.go      |  4 ++--
 9 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go
index 140851c17..5f91a0d1a 100644
--- a/pkg/sentry/socket/netstack/netstack.go
+++ b/pkg/sentry/socket/netstack/netstack.go
@@ -224,7 +224,7 @@ type commonEndpoint interface {
 
 	// SetSockOptInt implements tcpip.Endpoint.SetSockOptInt and
 	// transport.Endpoint.SetSockOptInt.
-	SetSockOptInt(opt tcpip.SockOpt, v int) *tcpip.Error
+	SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error
 
 	// GetSockOpt implements tcpip.Endpoint.GetSockOpt and
 	// transport.Endpoint.GetSockOpt.
@@ -232,7 +232,7 @@ type commonEndpoint interface {
 
 	// GetSockOptInt implements tcpip.Endpoint.GetSockOptInt and
 	// transport.Endpoint.GetSockOpt.
-	GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error)
+	GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error)
 }
 
 // SocketOperations encapsulates all the state needed to represent a network stack
diff --git a/pkg/sentry/socket/unix/transport/unix.go b/pkg/sentry/socket/unix/transport/unix.go
index 529a7a7a9..fcba49435 100644
--- a/pkg/sentry/socket/unix/transport/unix.go
+++ b/pkg/sentry/socket/unix/transport/unix.go
@@ -177,7 +177,7 @@ type Endpoint interface {
 
 	// SetSockOptInt sets a socket option for simple cases when a value has
 	// the int type.
-	SetSockOptInt(opt tcpip.SockOpt, v int) *tcpip.Error
+	SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error
 
 	// GetSockOpt gets a socket option. opt should be a pointer to one of the
 	// tcpip.*Option types.
@@ -185,7 +185,7 @@ type Endpoint interface {
 
 	// GetSockOptInt gets a socket option for simple cases when a return
 	// value has the int type.
-	GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error)
+	GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error)
 
 	// State returns the current state of the socket, as represented by Linux in
 	// procfs.
@@ -851,11 +851,11 @@ func (e *baseEndpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 	return nil
 }
 
-func (e *baseEndpoint) SetSockOptInt(opt tcpip.SockOpt, v int) *tcpip.Error {
+func (e *baseEndpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
 	return nil
 }
 
-func (e *baseEndpoint) GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error) {
+func (e *baseEndpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
 	switch opt {
 	case tcpip.ReceiveQueueSizeOption:
 		v := 0
diff --git a/pkg/tcpip/stack/transport_test.go b/pkg/tcpip/stack/transport_test.go
index 748ce4ea5..095346f0b 100644
--- a/pkg/tcpip/stack/transport_test.go
+++ b/pkg/tcpip/stack/transport_test.go
@@ -103,12 +103,12 @@ func (*fakeTransportEndpoint) SetSockOpt(interface{}) *tcpip.Error {
 }
 
 // SetSockOptInt sets a socket option. Currently not supported.
-func (*fakeTransportEndpoint) SetSockOptInt(tcpip.SockOpt, int) *tcpip.Error {
+func (*fakeTransportEndpoint) SetSockOptInt(tcpip.SockOptInt, int) *tcpip.Error {
 	return tcpip.ErrInvalidEndpointState
 }
 
 // GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
-func (*fakeTransportEndpoint) GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error) {
+func (*fakeTransportEndpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
 	return -1, tcpip.ErrUnknownProtocolOption
 }
 
diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go
index f62fd729f..b172d71b0 100644
--- a/pkg/tcpip/tcpip.go
+++ b/pkg/tcpip/tcpip.go
@@ -425,7 +425,7 @@ type Endpoint interface {
 
 	// SetSockOptInt sets a socket option, for simple cases where a value
 	// has the int type.
-	SetSockOptInt(opt SockOpt, v int) *Error
+	SetSockOptInt(opt SockOptInt, v int) *Error
 
 	// GetSockOpt gets a socket option. opt should be a pointer to one of the
 	// *Option types.
@@ -433,7 +433,7 @@ type Endpoint interface {
 
 	// GetSockOptInt gets a socket option for simple cases where a return
 	// value has the int type.
-	GetSockOptInt(SockOpt) (int, *Error)
+	GetSockOptInt(SockOptInt) (int, *Error)
 
 	// State returns a socket's lifecycle state. The returned value is
 	// protocol-specific and is primarily used for diagnostics.
@@ -488,13 +488,13 @@ type WriteOptions struct {
 	Atomic bool
 }
 
-// SockOpt represents socket options which values have the int type.
-type SockOpt int
+// SockOptInt represents socket options which values have the int type.
+type SockOptInt int
 
 const (
 	// ReceiveQueueSizeOption is used in GetSockOptInt to specify that the
 	// number of unread bytes in the input buffer should be returned.
-	ReceiveQueueSizeOption SockOpt = iota
+	ReceiveQueueSizeOption SockOptInt = iota
 
 	// SendBufferSizeOption is used by SetSockOptInt/GetSockOptInt to
 	// specify the send buffer size option.
diff --git a/pkg/tcpip/transport/icmp/endpoint.go b/pkg/tcpip/transport/icmp/endpoint.go
index 9c40931b5..5816ce49a 100644
--- a/pkg/tcpip/transport/icmp/endpoint.go
+++ b/pkg/tcpip/transport/icmp/endpoint.go
@@ -351,12 +351,12 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 }
 
 // SetSockOptInt sets a socket option. Currently not supported.
-func (e *endpoint) SetSockOptInt(opt tcpip.SockOpt, v int) *tcpip.Error {
+func (e *endpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
 	return nil
 }
 
 // GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
-func (e *endpoint) GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error) {
+func (e *endpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
 	switch opt {
 	case tcpip.ReceiveQueueSizeOption:
 		v := 0
diff --git a/pkg/tcpip/transport/packet/endpoint.go b/pkg/tcpip/transport/packet/endpoint.go
index 0010b5e5f..6360ce880 100644
--- a/pkg/tcpip/transport/packet/endpoint.go
+++ b/pkg/tcpip/transport/packet/endpoint.go
@@ -251,12 +251,12 @@ func (ep *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 }
 
 // SetSockOptInt implements tcpip.Endpoint.SetSockOptInt.
-func (ep *endpoint) SetSockOptInt(opt tcpip.SockOpt, v int) *tcpip.Error {
+func (ep *endpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
 	return tcpip.ErrUnknownProtocolOption
 }
 
 // GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
-func (ep *endpoint) GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error) {
+func (ep *endpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
 	return 0, tcpip.ErrNotSupported
 }
 
diff --git a/pkg/tcpip/transport/raw/endpoint.go b/pkg/tcpip/transport/raw/endpoint.go
index 5aafe2615..0fd9c456a 100644
--- a/pkg/tcpip/transport/raw/endpoint.go
+++ b/pkg/tcpip/transport/raw/endpoint.go
@@ -510,12 +510,12 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 }
 
 // SetSockOptInt implements tcpip.Endpoint.SetSockOptInt.
-func (ep *endpoint) SetSockOptInt(opt tcpip.SockOpt, v int) *tcpip.Error {
+func (e *endpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
 	return tcpip.ErrUnknownProtocolOption
 }
 
 // GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
-func (e *endpoint) GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error) {
+func (e *endpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
 	switch opt {
 	case tcpip.ReceiveQueueSizeOption:
 		v := 0
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index fe629aa40..f79154b95 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -1146,7 +1146,7 @@ func (e *endpoint) zeroReceiveWindow(scale uint8) bool {
 }
 
 // SetSockOptInt sets a socket option.
-func (e *endpoint) SetSockOptInt(opt tcpip.SockOpt, v int) *tcpip.Error {
+func (e *endpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
 	switch opt {
 	case tcpip.ReceiveBufferSizeOption:
 		// Make sure the receive buffer size is within the min and max
@@ -1447,7 +1447,7 @@ func (e *endpoint) readyReceiveSize() (int, *tcpip.Error) {
 }
 
 // GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
-func (e *endpoint) GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error) {
+func (e *endpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
 	switch opt {
 	case tcpip.ReceiveQueueSizeOption:
 		return e.readyReceiveSize()
diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go
index 1ac4705af..dae373ea7 100644
--- a/pkg/tcpip/transport/udp/endpoint.go
+++ b/pkg/tcpip/transport/udp/endpoint.go
@@ -457,7 +457,7 @@ func (e *endpoint) Peek([][]byte) (int64, tcpip.ControlMessages, *tcpip.Error) {
 }
 
 // SetSockOptInt implements tcpip.Endpoint.SetSockOptInt.
-func (e *endpoint) SetSockOptInt(opt tcpip.SockOpt, v int) *tcpip.Error {
+func (e *endpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
 	return nil
 }
 
@@ -661,7 +661,7 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 }
 
 // GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
-func (e *endpoint) GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error) {
+func (e *endpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
 	switch opt {
 	case tcpip.ReceiveQueueSizeOption:
 		v := 0
-- 
cgit v1.2.3


From e21c5840569155d39e8e11ac18cee99bc6d67469 Mon Sep 17 00:00:00 2001
From: Bert Muthalaly <stijlist@google.com>
Date: Wed, 8 Jan 2020 14:49:12 -0800
Subject: Combine various Create*NIC methods into CreateNICWithOptions.

PiperOrigin-RevId: 288779416
---
 pkg/tcpip/stack/ndp_test.go                        |  6 +--
 pkg/tcpip/stack/stack.go                           | 46 ++++++++++------------
 pkg/tcpip/stack/stack_test.go                      | 10 +++--
 pkg/tcpip/stack/transport_demuxer_test.go          |  5 ++-
 pkg/tcpip/transport/tcp/tcp_test.go                |  5 ++-
 pkg/tcpip/transport/tcp/testing/context/context.go | 10 +++--
 pkg/tcpip/transport/udp/udp_test.go                |  5 ++-
 runsc/boot/network.go                              |  5 ++-
 8 files changed, 47 insertions(+), 45 deletions(-)

diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go
index 8d89859ba..070d80c8d 100644
--- a/pkg/tcpip/stack/ndp_test.go
+++ b/pkg/tcpip/stack/ndp_test.go
@@ -2500,9 +2500,9 @@ func TestAutoGenAddrWithOpaqueIID(t *testing.T) {
 			SecretKey: secretKey,
 		},
 	})
-
-	if err := s.CreateNamedNIC(nicID, nicName, e); err != nil {
-		t.Fatalf("CreateNamedNIC(%d, %q, _) = %s", nicID, nicName, err)
+	opts := stack.NICOptions{Name: nicName}
+	if err := s.CreateNICWithOptions(nicID, e, opts); err != nil {
+		t.Fatalf("CreateNICWithOptions(%d, _, %+v, _) = %s", nicID, opts, err)
 	}
 
 	expectAutoGenAddrEvent := func(addr tcpip.AddressWithPrefix, eventType ndpAutoGenAddrEventType) {
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 807f910f6..fb7ac409e 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -796,9 +796,21 @@ func (s *Stack) NewPacketEndpoint(cooked bool, netProto tcpip.NetworkProtocolNum
 	return s.rawFactory.NewPacketEndpoint(s, cooked, netProto, waiterQueue)
 }
 
-// createNIC creates a NIC with the provided id and link-layer endpoint, and
-// optionally enable it.
-func (s *Stack) createNIC(id tcpip.NICID, name string, ep LinkEndpoint, enabled bool) *tcpip.Error {
+// NICOptions specifies the configuration of a NIC as it is being created.
+// The zero value creates an enabled, unnamed NIC.
+type NICOptions struct {
+	// Name specifies the name of the NIC.
+	Name string
+
+	// Disabled specifies whether to avoid calling Attach on the passed
+	// LinkEndpoint.
+	Disabled bool
+}
+
+// CreateNICWithOptions creates a NIC with the provided id, LinkEndpoint, and
+// NICOptions. See the documentation on type NICOptions for details on how
+// NICs can be configured.
+func (s *Stack) CreateNICWithOptions(id tcpip.NICID, ep LinkEndpoint, opts NICOptions) *tcpip.Error {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
@@ -807,38 +819,20 @@ func (s *Stack) createNIC(id tcpip.NICID, name string, ep LinkEndpoint, enabled
 		return tcpip.ErrDuplicateNICID
 	}
 
-	n := newNIC(s, id, name, ep)
+	n := newNIC(s, id, opts.Name, ep)
 
 	s.nics[id] = n
-	if enabled {
+	if !opts.Disabled {
 		return n.enable()
 	}
 
 	return nil
 }
 
-// CreateNIC creates a NIC with the provided id and link-layer endpoint.
+// CreateNIC creates a NIC with the provided id and LinkEndpoint and calls
+// `LinkEndpoint.Attach` to start delivering packets to it.
 func (s *Stack) CreateNIC(id tcpip.NICID, ep LinkEndpoint) *tcpip.Error {
-	return s.createNIC(id, "", ep, true)
-}
-
-// CreateNamedNIC creates a NIC with the provided id and link-layer endpoint,
-// and a human-readable name.
-func (s *Stack) CreateNamedNIC(id tcpip.NICID, name string, ep LinkEndpoint) *tcpip.Error {
-	return s.createNIC(id, name, ep, true)
-}
-
-// CreateDisabledNIC creates a NIC with the provided id and link-layer endpoint,
-// but leave it disable. Stack.EnableNIC must be called before the link-layer
-// endpoint starts delivering packets to it.
-func (s *Stack) CreateDisabledNIC(id tcpip.NICID, ep LinkEndpoint) *tcpip.Error {
-	return s.createNIC(id, "", ep, false)
-}
-
-// CreateDisabledNamedNIC is a combination of CreateNamedNIC and
-// CreateDisabledNIC.
-func (s *Stack) CreateDisabledNamedNIC(id tcpip.NICID, name string, ep LinkEndpoint) *tcpip.Error {
-	return s.createNIC(id, name, ep, false)
+	return s.CreateNICWithOptions(id, ep, NICOptions{})
 }
 
 // EnableNIC enables the given NIC so that the link-layer endpoint can start
diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go
index 33f20579f..9ac50bb23 100644
--- a/pkg/tcpip/stack/stack_test.go
+++ b/pkg/tcpip/stack/stack_test.go
@@ -2097,8 +2097,9 @@ func TestNICAutoGenAddrWithOpaque(t *testing.T) {
 
 			e := channel.New(10, 1280, test.linkAddr)
 			s := stack.New(opts)
-			if err := s.CreateNamedNIC(nicID, test.nicName, e); err != nil {
-				t.Fatalf("CreateNamedNIC(%d, %q, _) = %s", nicID, test.nicName, err)
+			nicOpts := stack.NICOptions{Name: test.nicName}
+			if err := s.CreateNICWithOptions(nicID, e, nicOpts); err != nil {
+				t.Fatalf("CreateNICWithOptions(%d, _, %+v) = %s", nicID, opts, err)
 			}
 
 			addr, err := s.GetMainNICAddress(nicID, header.IPv6ProtocolNumber)
@@ -2156,8 +2157,9 @@ func TestNoLinkLocalAutoGenForLoopbackNIC(t *testing.T) {
 
 			e := loopback.New()
 			s := stack.New(opts)
-			if err := s.CreateNamedNIC(nicID, nicName, e); err != nil {
-				t.Fatalf("CreateNamedNIC(%d, %q, _) = %s", nicID, nicName, err)
+			nicOpts := stack.NICOptions{Name: nicName}
+			if err := s.CreateNICWithOptions(nicID, e, nicOpts); err != nil {
+				t.Fatalf("CreateNICWithOptions(%d, _, %+v) = %s", nicID, nicOpts, err)
 			}
 
 			addr, err := s.GetMainNICAddress(nicID, header.IPv6ProtocolNumber)
diff --git a/pkg/tcpip/stack/transport_demuxer_test.go b/pkg/tcpip/stack/transport_demuxer_test.go
index 3b28b06d0..33dbc0536 100644
--- a/pkg/tcpip/stack/transport_demuxer_test.go
+++ b/pkg/tcpip/stack/transport_demuxer_test.go
@@ -80,8 +80,9 @@ func newDualTestContextMultiNic(t *testing.T, mtu uint32, linkEpNames []string)
 	for i, linkEpName := range linkEpNames {
 		channelEP := channel.New(256, mtu, "")
 		nicID := tcpip.NICID(i + 1)
-		if err := s.CreateNamedNIC(nicID, linkEpName, channelEP); err != nil {
-			t.Fatalf("CreateNIC failed: %v", err)
+		opts := stack.NICOptions{Name: linkEpName}
+		if err := s.CreateNICWithOptions(nicID, channelEP, opts); err != nil {
+			t.Fatalf("CreateNICWithOptions(_, _, %+v) failed: %v", opts, err)
 		}
 		linkEPs[linkEpName] = channelEP
 
diff --git a/pkg/tcpip/transport/tcp/tcp_test.go b/pkg/tcpip/transport/tcp/tcp_test.go
index e8fe4dab5..9d7b0910d 100644
--- a/pkg/tcpip/transport/tcp/tcp_test.go
+++ b/pkg/tcpip/transport/tcp/tcp_test.go
@@ -3794,8 +3794,9 @@ func TestBindToDeviceOption(t *testing.T) {
 	}
 	defer ep.Close()
 
-	if err := s.CreateNamedNIC(321, "my_device", loopback.New()); err != nil {
-		t.Errorf("CreateNamedNIC failed: %v", err)
+	opts := stack.NICOptions{Name: "my_device"}
+	if err := s.CreateNICWithOptions(321, loopback.New(), opts); err != nil {
+		t.Errorf("CreateNICWithOptions(_, _, %+v) failed: %v", opts, err)
 	}
 
 	// Make an nameless NIC.
diff --git a/pkg/tcpip/transport/tcp/testing/context/context.go b/pkg/tcpip/transport/tcp/testing/context/context.go
index b0a376eba..50c81aa65 100644
--- a/pkg/tcpip/transport/tcp/testing/context/context.go
+++ b/pkg/tcpip/transport/tcp/testing/context/context.go
@@ -158,15 +158,17 @@ func New(t *testing.T, mtu uint32) *Context {
 	if testing.Verbose() {
 		wep = sniffer.New(ep)
 	}
-	if err := s.CreateNamedNIC(1, "nic1", wep); err != nil {
-		t.Fatalf("CreateNIC failed: %v", err)
+	opts := stack.NICOptions{Name: "nic1"}
+	if err := s.CreateNICWithOptions(1, wep, opts); err != nil {
+		t.Fatalf("CreateNICWithOptions(_, _, %+v) failed: %v", opts, err)
 	}
 	wep2 := stack.LinkEndpoint(channel.New(1000, mtu, ""))
 	if testing.Verbose() {
 		wep2 = sniffer.New(channel.New(1000, mtu, ""))
 	}
-	if err := s.CreateNamedNIC(2, "nic2", wep2); err != nil {
-		t.Fatalf("CreateNIC failed: %v", err)
+	opts2 := stack.NICOptions{Name: "nic2"}
+	if err := s.CreateNICWithOptions(2, wep2, opts2); err != nil {
+		t.Fatalf("CreateNICWithOptions(_, _, %+v) failed: %v", opts2, err)
 	}
 
 	if err := s.AddAddress(1, ipv4.ProtocolNumber, StackAddr); err != nil {
diff --git a/pkg/tcpip/transport/udp/udp_test.go b/pkg/tcpip/transport/udp/udp_test.go
index 7051a7a9c..65382b7f1 100644
--- a/pkg/tcpip/transport/udp/udp_test.go
+++ b/pkg/tcpip/transport/udp/udp_test.go
@@ -508,8 +508,9 @@ func TestBindToDeviceOption(t *testing.T) {
 	}
 	defer ep.Close()
 
-	if err := s.CreateNamedNIC(321, "my_device", loopback.New()); err != nil {
-		t.Errorf("CreateNamedNIC failed: %v", err)
+	opts := stack.NICOptions{Name: "my_device"}
+	if err := s.CreateNICWithOptions(321, loopback.New(), opts); err != nil {
+		t.Errorf("CreateNICWithOptions(_, _, %+v) failed: %v", opts, err)
 	}
 
 	// Make an nameless NIC.
diff --git a/runsc/boot/network.go b/runsc/boot/network.go
index 0240fe323..6a8765ec8 100644
--- a/runsc/boot/network.go
+++ b/runsc/boot/network.go
@@ -219,8 +219,9 @@ func (n *Network) CreateLinksAndRoutes(args *CreateLinksAndRoutesArgs, _ *struct
 // createNICWithAddrs creates a NIC in the network stack and adds the given
 // addresses.
 func (n *Network) createNICWithAddrs(id tcpip.NICID, name string, ep stack.LinkEndpoint, addrs []net.IP) error {
-	if err := n.Stack.CreateNamedNIC(id, name, sniffer.New(ep)); err != nil {
-		return fmt.Errorf("CreateNamedNIC(%v, %v, %v) failed: %v", id, name, ep, err)
+	opts := stack.NICOptions{Name: name}
+	if err := n.Stack.CreateNICWithOptions(id, sniffer.New(ep), opts); err != nil {
+		return fmt.Errorf("CreateNICWithOptions(%d, _, %+v) failed: %v", id, opts, err)
 	}
 
 	// Always start with an arp address for the NIC.
-- 
cgit v1.2.3


From d530df2f95c3f75488ecc56b8fd205c3ee0966f8 Mon Sep 17 00:00:00 2001
From: Tamir Duberstein <tamird@google.com>
Date: Wed, 8 Jan 2020 15:39:22 -0800
Subject: Introduce tcpip.SockOptBool

...and port V6OnlyOption to it.

PiperOrigin-RevId: 288789451
---
 pkg/sentry/socket/netstack/netstack.go             | 21 ++++--
 pkg/sentry/socket/unix/transport/unix.go           | 16 +++++
 pkg/tcpip/stack/ndp_test.go                        | 15 ++---
 pkg/tcpip/stack/transport_demuxer_test.go          | 48 +++++++-------
 pkg/tcpip/stack/transport_test.go                  | 10 +++
 pkg/tcpip/tcpip.go                                 | 21 ++++--
 pkg/tcpip/transport/icmp/endpoint.go               | 10 +++
 pkg/tcpip/transport/packet/endpoint.go             | 22 +++++--
 pkg/tcpip/transport/raw/endpoint.go                | 40 +++++++-----
 pkg/tcpip/transport/tcp/dual_stack_test.go         |  8 +--
 pkg/tcpip/transport/tcp/endpoint.go                | 75 ++++++++++++----------
 pkg/tcpip/transport/tcp/tcp_test.go                |  8 +--
 pkg/tcpip/transport/tcp/testing/context/context.go |  6 +-
 pkg/tcpip/transport/udp/endpoint.go                | 60 +++++++++--------
 pkg/tcpip/transport/udp/udp_test.go                |  2 +-
 15 files changed, 224 insertions(+), 138 deletions(-)

diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go
index 5f91a0d1a..9e0d69046 100644
--- a/pkg/sentry/socket/netstack/netstack.go
+++ b/pkg/sentry/socket/netstack/netstack.go
@@ -222,6 +222,10 @@ type commonEndpoint interface {
 	// transport.Endpoint.SetSockOpt.
 	SetSockOpt(interface{}) *tcpip.Error
 
+	// SetSockOptBool implements tcpip.Endpoint.SetSockOptBool and
+	// transport.Endpoint.SetSockOptBool.
+	SetSockOptBool(opt tcpip.SockOptBool, v bool) *tcpip.Error
+
 	// SetSockOptInt implements tcpip.Endpoint.SetSockOptInt and
 	// transport.Endpoint.SetSockOptInt.
 	SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error
@@ -230,6 +234,10 @@ type commonEndpoint interface {
 	// transport.Endpoint.GetSockOpt.
 	GetSockOpt(interface{}) *tcpip.Error
 
+	// GetSockOptBool implements tcpip.Endpoint.GetSockOptBool and
+	// transport.Endpoint.GetSockOpt.
+	GetSockOptBool(opt tcpip.SockOptBool) (bool, *tcpip.Error)
+
 	// GetSockOptInt implements tcpip.Endpoint.GetSockOptInt and
 	// transport.Endpoint.GetSockOpt.
 	GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error)
@@ -1213,12 +1221,15 @@ func getSockOptIPv6(t *kernel.Task, ep commonEndpoint, name, outLen int) (interf
 			return nil, syserr.ErrInvalidArgument
 		}
 
-		var v tcpip.V6OnlyOption
-		if err := ep.GetSockOpt(&v); err != nil {
+		v, err := ep.GetSockOptBool(tcpip.V6OnlyOption)
+		if err != nil {
 			return nil, syserr.TranslateNetstackError(err)
 		}
-
-		return int32(v), nil
+		var o uint32
+		if v {
+			o = 1
+		}
+		return int32(o), nil
 
 	case linux.IPV6_PATHMTU:
 		t.Kernel().EmitUnimplementedEvent(t)
@@ -1621,7 +1632,7 @@ func setSockOptIPv6(t *kernel.Task, ep commonEndpoint, name int, optVal []byte)
 		}
 
 		v := usermem.ByteOrder.Uint32(optVal)
-		return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.V6OnlyOption(v)))
+		return syserr.TranslateNetstackError(ep.SetSockOptBool(tcpip.V6OnlyOption, v != 0))
 
 	case linux.IPV6_ADD_MEMBERSHIP,
 		linux.IPV6_DROP_MEMBERSHIP,
diff --git a/pkg/sentry/socket/unix/transport/unix.go b/pkg/sentry/socket/unix/transport/unix.go
index fcba49435..37c7ac3c1 100644
--- a/pkg/sentry/socket/unix/transport/unix.go
+++ b/pkg/sentry/socket/unix/transport/unix.go
@@ -175,6 +175,10 @@ type Endpoint interface {
 	// types.
 	SetSockOpt(opt interface{}) *tcpip.Error
 
+	// SetSockOptBool sets a socket option for simple cases when a value has
+	// the int type.
+	SetSockOptBool(opt tcpip.SockOptBool, v bool) *tcpip.Error
+
 	// SetSockOptInt sets a socket option for simple cases when a value has
 	// the int type.
 	SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error
@@ -183,6 +187,10 @@ type Endpoint interface {
 	// tcpip.*Option types.
 	GetSockOpt(opt interface{}) *tcpip.Error
 
+	// GetSockOptBool gets a socket option for simple cases when a return
+	// value has the int type.
+	GetSockOptBool(opt tcpip.SockOptBool) (bool, *tcpip.Error)
+
 	// GetSockOptInt gets a socket option for simple cases when a return
 	// value has the int type.
 	GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error)
@@ -851,10 +859,18 @@ func (e *baseEndpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 	return nil
 }
 
+func (e *baseEndpoint) SetSockOptBool(opt tcpip.SockOptBool, v bool) *tcpip.Error {
+	return nil
+}
+
 func (e *baseEndpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
 	return nil
 }
 
+func (e *baseEndpoint) GetSockOptBool(opt tcpip.SockOptBool) (bool, *tcpip.Error) {
+	return false, tcpip.ErrUnknownProtocolOption
+}
+
 func (e *baseEndpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
 	switch opt {
 	case tcpip.ReceiveQueueSizeOption:
diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go
index 070d80c8d..e51462a55 100644
--- a/pkg/tcpip/stack/ndp_test.go
+++ b/pkg/tcpip/stack/ndp_test.go
@@ -1701,9 +1701,8 @@ func addrForNewConnection(t *testing.T, s *stack.Stack) tcpip.Address {
 		t.Fatalf("s.NewEndpoint(%d, %d, _): %s", header.UDPProtocolNumber, header.IPv6ProtocolNumber, err)
 	}
 	defer ep.Close()
-	v := tcpip.V6OnlyOption(1)
-	if err := ep.SetSockOpt(v); err != nil {
-		t.Fatalf("SetSockOpt(%+v): %s", v, err)
+	if err := ep.SetSockOptBool(tcpip.V6OnlyOption, true); err != nil {
+		t.Fatalf("SetSockOpt(tcpip.V6OnlyOption, true): %s", err)
 	}
 	if err := ep.Connect(dstAddr); err != nil {
 		t.Fatalf("ep.Connect(%+v): %s", dstAddr, err)
@@ -1728,9 +1727,8 @@ func addrForNewConnectionWithAddr(t *testing.T, s *stack.Stack, addr tcpip.FullA
 		t.Fatalf("s.NewEndpoint(%d, %d, _): %s", header.UDPProtocolNumber, header.IPv6ProtocolNumber, err)
 	}
 	defer ep.Close()
-	v := tcpip.V6OnlyOption(1)
-	if err := ep.SetSockOpt(v); err != nil {
-		t.Fatalf("SetSockOpt(%+v): %s", v, err)
+	if err := ep.SetSockOptBool(tcpip.V6OnlyOption, true); err != nil {
+		t.Fatalf("SetSockOpt(tcpip.V6OnlyOption, true): %s", err)
 	}
 	if err := ep.Bind(addr); err != nil {
 		t.Fatalf("ep.Bind(%+v): %s", addr, err)
@@ -2066,9 +2064,8 @@ func TestAutoGenAddrTimerDeprecation(t *testing.T) {
 		t.Fatalf("s.NewEndpoint(%d, %d, _): %s", header.UDPProtocolNumber, header.IPv6ProtocolNumber, err)
 	}
 	defer ep.Close()
-	v := tcpip.V6OnlyOption(1)
-	if err := ep.SetSockOpt(v); err != nil {
-		t.Fatalf("SetSockOpt(%+v): %s", v, err)
+	if err := ep.SetSockOptBool(tcpip.V6OnlyOption, true); err != nil {
+		t.Fatalf("SetSockOpt(tcpip.V6OnlyOption, true): %s", err)
 	}
 
 	if err := ep.Connect(dstAddr); err != tcpip.ErrNoRoute {
diff --git a/pkg/tcpip/stack/transport_demuxer_test.go b/pkg/tcpip/stack/transport_demuxer_test.go
index 33dbc0536..df5ced887 100644
--- a/pkg/tcpip/stack/transport_demuxer_test.go
+++ b/pkg/tcpip/stack/transport_demuxer_test.go
@@ -61,11 +61,7 @@ func (c *testContext) createV6Endpoint(v6only bool) {
 		c.t.Fatalf("NewEndpoint failed: %v", err)
 	}
 
-	var v tcpip.V6OnlyOption
-	if v6only {
-		v = 1
-	}
-	if err := c.ep.SetSockOpt(v); err != nil {
+	if err := c.ep.SetSockOptBool(tcpip.V6OnlyOption, v6only); err != nil {
 		c.t.Fatalf("SetSockOpt failed: %v", err)
 	}
 }
@@ -201,54 +197,54 @@ func TestDistribution(t *testing.T) {
 			"BindPortReuse",
 			// 5 endpoints that all have reuse set.
 			[]endpointSockopts{
-				endpointSockopts{1, ""},
-				endpointSockopts{1, ""},
-				endpointSockopts{1, ""},
-				endpointSockopts{1, ""},
-				endpointSockopts{1, ""},
+				{1, ""},
+				{1, ""},
+				{1, ""},
+				{1, ""},
+				{1, ""},
 			},
 			map[string][]float64{
 				// Injected packets on dev0 get distributed evenly.
-				"dev0": []float64{0.2, 0.2, 0.2, 0.2, 0.2},
+				"dev0": {0.2, 0.2, 0.2, 0.2, 0.2},
 			},
 		},
 		{
 			"BindToDevice",
 			// 3 endpoints with various bindings.
 			[]endpointSockopts{
-				endpointSockopts{0, "dev0"},
-				endpointSockopts{0, "dev1"},
-				endpointSockopts{0, "dev2"},
+				{0, "dev0"},
+				{0, "dev1"},
+				{0, "dev2"},
 			},
 			map[string][]float64{
 				// Injected packets on dev0 go only to the endpoint bound to dev0.
-				"dev0": []float64{1, 0, 0},
+				"dev0": {1, 0, 0},
 				// Injected packets on dev1 go only to the endpoint bound to dev1.
-				"dev1": []float64{0, 1, 0},
+				"dev1": {0, 1, 0},
 				// Injected packets on dev2 go only to the endpoint bound to dev2.
-				"dev2": []float64{0, 0, 1},
+				"dev2": {0, 0, 1},
 			},
 		},
 		{
 			"ReuseAndBindToDevice",
 			// 6 endpoints with various bindings.
 			[]endpointSockopts{
-				endpointSockopts{1, "dev0"},
-				endpointSockopts{1, "dev0"},
-				endpointSockopts{1, "dev1"},
-				endpointSockopts{1, "dev1"},
-				endpointSockopts{1, "dev1"},
-				endpointSockopts{1, ""},
+				{1, "dev0"},
+				{1, "dev0"},
+				{1, "dev1"},
+				{1, "dev1"},
+				{1, "dev1"},
+				{1, ""},
 			},
 			map[string][]float64{
 				// Injected packets on dev0 get distributed among endpoints bound to
 				// dev0.
-				"dev0": []float64{0.5, 0.5, 0, 0, 0, 0},
+				"dev0": {0.5, 0.5, 0, 0, 0, 0},
 				// Injected packets on dev1 get distributed among endpoints bound to
 				// dev1 or unbound.
-				"dev1": []float64{0, 0, 1. / 3, 1. / 3, 1. / 3, 0},
+				"dev1": {0, 0, 1. / 3, 1. / 3, 1. / 3, 0},
 				// Injected packets on dev999 go only to the unbound.
-				"dev999": []float64{0, 0, 0, 0, 0, 1},
+				"dev999": {0, 0, 0, 0, 0, 1},
 			},
 		},
 	} {
diff --git a/pkg/tcpip/stack/transport_test.go b/pkg/tcpip/stack/transport_test.go
index 095346f0b..f50604a8a 100644
--- a/pkg/tcpip/stack/transport_test.go
+++ b/pkg/tcpip/stack/transport_test.go
@@ -102,11 +102,21 @@ func (*fakeTransportEndpoint) SetSockOpt(interface{}) *tcpip.Error {
 	return tcpip.ErrInvalidEndpointState
 }
 
+// SetSockOptBool sets a socket option. Currently not supported.
+func (*fakeTransportEndpoint) SetSockOptBool(tcpip.SockOptBool, bool) *tcpip.Error {
+	return tcpip.ErrInvalidEndpointState
+}
+
 // SetSockOptInt sets a socket option. Currently not supported.
 func (*fakeTransportEndpoint) SetSockOptInt(tcpip.SockOptInt, int) *tcpip.Error {
 	return tcpip.ErrInvalidEndpointState
 }
 
+// GetSockOptBool implements tcpip.Endpoint.GetSockOptBool.
+func (*fakeTransportEndpoint) GetSockOptBool(opt tcpip.SockOptBool) (bool, *tcpip.Error) {
+	return false, tcpip.ErrUnknownProtocolOption
+}
+
 // GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
 func (*fakeTransportEndpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
 	return -1, tcpip.ErrUnknownProtocolOption
diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go
index b172d71b0..1eca76c30 100644
--- a/pkg/tcpip/tcpip.go
+++ b/pkg/tcpip/tcpip.go
@@ -423,6 +423,10 @@ type Endpoint interface {
 	// SetSockOpt sets a socket option. opt should be one of the *Option types.
 	SetSockOpt(opt interface{}) *Error
 
+	// SetSockOptBool sets a socket option, for simple cases where a value
+	// has the bool type.
+	SetSockOptBool(opt SockOptBool, v bool) *Error
+
 	// SetSockOptInt sets a socket option, for simple cases where a value
 	// has the int type.
 	SetSockOptInt(opt SockOptInt, v int) *Error
@@ -431,6 +435,10 @@ type Endpoint interface {
 	// *Option types.
 	GetSockOpt(opt interface{}) *Error
 
+	// GetSockOptBool gets a socket option for simple cases where a return
+	// value has the bool type.
+	GetSockOptBool(SockOptBool) (bool, *Error)
+
 	// GetSockOptInt gets a socket option for simple cases where a return
 	// value has the int type.
 	GetSockOptInt(SockOptInt) (int, *Error)
@@ -488,6 +496,15 @@ type WriteOptions struct {
 	Atomic bool
 }
 
+// SockOptBool represents socket options which values have the bool type.
+type SockOptBool int
+
+const (
+	// V6OnlyOption is used by {G,S}etSockOptBool to specify whether an IPv6
+	// socket is to be restricted to sending and receiving IPv6 packets only.
+	V6OnlyOption SockOptBool = iota
+)
+
 // SockOptInt represents socket options which values have the int type.
 type SockOptInt int
 
@@ -521,10 +538,6 @@ const (
 // the endpoint should be cleared and returned.
 type ErrorOption struct{}
 
-// V6OnlyOption is used by SetSockOpt/GetSockOpt to specify whether an IPv6
-// socket is to be restricted to sending and receiving IPv6 packets only.
-type V6OnlyOption int
-
 // CorkOption is used by SetSockOpt/GetSockOpt to specify if data should be
 // held until segments are full by the TCP transport protocol.
 type CorkOption int
diff --git a/pkg/tcpip/transport/icmp/endpoint.go b/pkg/tcpip/transport/icmp/endpoint.go
index 5816ce49a..c7ce74cdd 100644
--- a/pkg/tcpip/transport/icmp/endpoint.go
+++ b/pkg/tcpip/transport/icmp/endpoint.go
@@ -350,11 +350,21 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 	return nil
 }
 
+// SetSockOptBool sets a socket option. Currently not supported.
+func (e *endpoint) SetSockOptBool(opt tcpip.SockOptBool, v bool) *tcpip.Error {
+	return nil
+}
+
 // SetSockOptInt sets a socket option. Currently not supported.
 func (e *endpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
 	return nil
 }
 
+// GetSockOptBool implements tcpip.Endpoint.GetSockOptBool.
+func (e *endpoint) GetSockOptBool(opt tcpip.SockOptBool) (bool, *tcpip.Error) {
+	return false, tcpip.ErrUnknownProtocolOption
+}
+
 // GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
 func (e *endpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
 	switch opt {
diff --git a/pkg/tcpip/transport/packet/endpoint.go b/pkg/tcpip/transport/packet/endpoint.go
index 6360ce880..07ffa8aba 100644
--- a/pkg/tcpip/transport/packet/endpoint.go
+++ b/pkg/tcpip/transport/packet/endpoint.go
@@ -247,17 +247,17 @@ func (ep *endpoint) Readiness(mask waiter.EventMask) waiter.EventMask {
 // used with SetSockOpt, and this function always returns
 // tcpip.ErrNotSupported.
 func (ep *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
-	return tcpip.ErrNotSupported
+	return tcpip.ErrUnknownProtocolOption
 }
 
-// SetSockOptInt implements tcpip.Endpoint.SetSockOptInt.
-func (ep *endpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
+// SetSockOptBool implements tcpip.Endpoint.SetSockOptBool.
+func (ep *endpoint) SetSockOptBool(opt tcpip.SockOptBool, v bool) *tcpip.Error {
 	return tcpip.ErrUnknownProtocolOption
 }
 
-// GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
-func (ep *endpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
-	return 0, tcpip.ErrNotSupported
+// SetSockOptInt implements tcpip.Endpoint.SetSockOptInt.
+func (ep *endpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
+	return tcpip.ErrUnknownProtocolOption
 }
 
 // GetSockOpt implements tcpip.Endpoint.GetSockOpt.
@@ -265,6 +265,16 @@ func (ep *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 	return tcpip.ErrNotSupported
 }
 
+// GetSockOptBool implements tcpip.Endpoint.GetSockOptBool.
+func (ep *endpoint) GetSockOptBool(opt tcpip.SockOptBool) (bool, *tcpip.Error) {
+	return false, tcpip.ErrNotSupported
+}
+
+// GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
+func (ep *endpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
+	return 0, tcpip.ErrNotSupported
+}
+
 // HandlePacket implements stack.PacketEndpoint.HandlePacket.
 func (ep *endpoint) HandlePacket(nicID tcpip.NICID, localAddr tcpip.LinkAddress, netProto tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer) {
 	ep.rcvMu.Lock()
diff --git a/pkg/tcpip/transport/raw/endpoint.go b/pkg/tcpip/transport/raw/endpoint.go
index 0fd9c456a..85f7eb76b 100644
--- a/pkg/tcpip/transport/raw/endpoint.go
+++ b/pkg/tcpip/transport/raw/endpoint.go
@@ -509,11 +509,36 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 	return tcpip.ErrUnknownProtocolOption
 }
 
+// SetSockOptBool implements tcpip.Endpoint.SetSockOptBool.
+func (e *endpoint) SetSockOptBool(opt tcpip.SockOptBool, v bool) *tcpip.Error {
+	return tcpip.ErrUnknownProtocolOption
+}
+
 // SetSockOptInt implements tcpip.Endpoint.SetSockOptInt.
 func (e *endpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
 	return tcpip.ErrUnknownProtocolOption
 }
 
+// GetSockOpt implements tcpip.Endpoint.GetSockOpt.
+func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
+	switch o := opt.(type) {
+	case tcpip.ErrorOption:
+		return nil
+
+	case *tcpip.KeepaliveEnabledOption:
+		*o = 0
+		return nil
+
+	default:
+		return tcpip.ErrUnknownProtocolOption
+	}
+}
+
+// GetSockOptBool implements tcpip.Endpoint.GetSockOptBool.
+func (e *endpoint) GetSockOptBool(opt tcpip.SockOptBool) (bool, *tcpip.Error) {
+	return false, tcpip.ErrUnknownProtocolOption
+}
+
 // GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
 func (e *endpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
 	switch opt {
@@ -544,21 +569,6 @@ func (e *endpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
 	return -1, tcpip.ErrUnknownProtocolOption
 }
 
-// GetSockOpt implements tcpip.Endpoint.GetSockOpt.
-func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
-	switch o := opt.(type) {
-	case tcpip.ErrorOption:
-		return nil
-
-	case *tcpip.KeepaliveEnabledOption:
-		*o = 0
-		return nil
-
-	default:
-		return tcpip.ErrUnknownProtocolOption
-	}
-}
-
 // HandlePacket implements stack.RawTransportEndpoint.HandlePacket.
 func (e *endpoint) HandlePacket(route *stack.Route, pkt tcpip.PacketBuffer) {
 	e.rcvMu.Lock()
diff --git a/pkg/tcpip/transport/tcp/dual_stack_test.go b/pkg/tcpip/transport/tcp/dual_stack_test.go
index dfaa4a559..4f361b226 100644
--- a/pkg/tcpip/transport/tcp/dual_stack_test.go
+++ b/pkg/tcpip/transport/tcp/dual_stack_test.go
@@ -391,9 +391,8 @@ func testV4Accept(t *testing.T, c *context.Context) {
 	// Make sure we get the same error when calling the original ep and the
 	// new one. This validates that v4-mapped endpoints are still able to
 	// query the V6Only flag, whereas pure v4 endpoints are not.
-	var v tcpip.V6OnlyOption
-	expected := c.EP.GetSockOpt(&v)
-	if err := nep.GetSockOpt(&v); err != expected {
+	_, expected := c.EP.GetSockOptBool(tcpip.V6OnlyOption)
+	if _, err := nep.GetSockOptBool(tcpip.V6OnlyOption); err != expected {
 		t.Fatalf("GetSockOpt returned unexpected value: got %v, want %v", err, expected)
 	}
 
@@ -531,8 +530,7 @@ func TestV6AcceptOnV6(t *testing.T) {
 
 	// Make sure we can still query the v6 only status of the new endpoint,
 	// that is, that it is in fact a v6 socket.
-	var v tcpip.V6OnlyOption
-	if err := nep.GetSockOpt(&v); err != nil {
+	if _, err := nep.GetSockOptBool(tcpip.V6OnlyOption); err != nil {
 		t.Fatalf("GetSockOpt failed failed: %v", err)
 	}
 
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index f79154b95..2ac1b6877 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -1145,6 +1145,29 @@ func (e *endpoint) zeroReceiveWindow(scale uint8) bool {
 	return ((e.rcvBufSize - e.rcvBufUsed) >> scale) == 0
 }
 
+// SetSockOptBool sets a socket option.
+func (e *endpoint) SetSockOptBool(opt tcpip.SockOptBool, v bool) *tcpip.Error {
+	switch opt {
+	case tcpip.V6OnlyOption:
+		// We only recognize this option on v6 endpoints.
+		if e.NetProto != header.IPv6ProtocolNumber {
+			return tcpip.ErrInvalidEndpointState
+		}
+
+		e.mu.Lock()
+		defer e.mu.Unlock()
+
+		// We only allow this to be set when we're in the initial state.
+		if e.state != StateInitial {
+			return tcpip.ErrInvalidEndpointState
+		}
+
+		e.v6only = v
+	}
+
+	return nil
+}
+
 // SetSockOptInt sets a socket option.
 func (e *endpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
 	switch opt {
@@ -1289,23 +1312,6 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 		e.notifyProtocolGoroutine(notifyMSSChanged)
 		return nil
 
-	case tcpip.V6OnlyOption:
-		// We only recognize this option on v6 endpoints.
-		if e.NetProto != header.IPv6ProtocolNumber {
-			return tcpip.ErrInvalidEndpointState
-		}
-
-		e.mu.Lock()
-		defer e.mu.Unlock()
-
-		// We only allow this to be set when we're in the initial state.
-		if e.state != StateInitial {
-			return tcpip.ErrInvalidEndpointState
-		}
-
-		e.v6only = v != 0
-		return nil
-
 	case tcpip.TTLOption:
 		e.mu.Lock()
 		e.ttl = uint8(v)
@@ -1446,6 +1452,25 @@ func (e *endpoint) readyReceiveSize() (int, *tcpip.Error) {
 	return e.rcvBufUsed, nil
 }
 
+// GetSockOptBool implements tcpip.Endpoint.GetSockOptBool.
+func (e *endpoint) GetSockOptBool(opt tcpip.SockOptBool) (bool, *tcpip.Error) {
+	switch opt {
+	case tcpip.V6OnlyOption:
+		// We only recognize this option on v6 endpoints.
+		if e.NetProto != header.IPv6ProtocolNumber {
+			return false, tcpip.ErrUnknownProtocolOption
+		}
+
+		e.mu.Lock()
+		v := e.v6only
+		e.mu.Unlock()
+
+		return v, nil
+	}
+
+	return false, tcpip.ErrUnknownProtocolOption
+}
+
 // GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
 func (e *endpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
 	switch opt {
@@ -1540,22 +1565,6 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 		}
 		return nil
 
-	case *tcpip.V6OnlyOption:
-		// We only recognize this option on v6 endpoints.
-		if e.NetProto != header.IPv6ProtocolNumber {
-			return tcpip.ErrUnknownProtocolOption
-		}
-
-		e.mu.Lock()
-		v := e.v6only
-		e.mu.Unlock()
-
-		*o = 0
-		if v {
-			*o = 1
-		}
-		return nil
-
 	case *tcpip.TTLOption:
 		e.mu.Lock()
 		*o = tcpip.TTLOption(e.ttl)
diff --git a/pkg/tcpip/transport/tcp/tcp_test.go b/pkg/tcpip/transport/tcp/tcp_test.go
index 9d7b0910d..15745ebd4 100644
--- a/pkg/tcpip/transport/tcp/tcp_test.go
+++ b/pkg/tcpip/transport/tcp/tcp_test.go
@@ -4028,12 +4028,12 @@ func TestConnectAvoidsBoundPorts(t *testing.T) {
 												switch network {
 												case "ipv4":
 												case "ipv6":
-													if err := ep.SetSockOpt(tcpip.V6OnlyOption(1)); err != nil {
-														t.Fatalf("SetSockOpt(V6OnlyOption(1)) failed: %v", err)
+													if err := ep.SetSockOptBool(tcpip.V6OnlyOption, true); err != nil {
+														t.Fatalf("SetSockOpt(V6OnlyOption(true)) failed: %v", err)
 													}
 												case "dual":
-													if err := ep.SetSockOpt(tcpip.V6OnlyOption(0)); err != nil {
-														t.Fatalf("SetSockOpt(V6OnlyOption(0)) failed: %v", err)
+													if err := ep.SetSockOptBool(tcpip.V6OnlyOption, false); err != nil {
+														t.Fatalf("SetSockOpt(V6OnlyOption(false)) failed: %v", err)
 													}
 												default:
 													t.Fatalf("unknown network: '%s'", network)
diff --git a/pkg/tcpip/transport/tcp/testing/context/context.go b/pkg/tcpip/transport/tcp/testing/context/context.go
index 50c81aa65..822907998 100644
--- a/pkg/tcpip/transport/tcp/testing/context/context.go
+++ b/pkg/tcpip/transport/tcp/testing/context/context.go
@@ -475,11 +475,7 @@ func (c *Context) CreateV6Endpoint(v6only bool) {
 		c.t.Fatalf("NewEndpoint failed: %v", err)
 	}
 
-	var v tcpip.V6OnlyOption
-	if v6only {
-		v = 1
-	}
-	if err := c.EP.SetSockOpt(v); err != nil {
+	if err := c.EP.SetSockOptBool(tcpip.V6OnlyOption, v6only); err != nil {
 		c.t.Fatalf("SetSockOpt failed failed: %v", err)
 	}
 }
diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go
index dae373ea7..1a5ee6317 100644
--- a/pkg/tcpip/transport/udp/endpoint.go
+++ b/pkg/tcpip/transport/udp/endpoint.go
@@ -456,14 +456,9 @@ func (e *endpoint) Peek([][]byte) (int64, tcpip.ControlMessages, *tcpip.Error) {
 	return 0, tcpip.ControlMessages{}, nil
 }
 
-// SetSockOptInt implements tcpip.Endpoint.SetSockOptInt.
-func (e *endpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
-	return nil
-}
-
-// SetSockOpt implements tcpip.Endpoint.SetSockOpt.
-func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
-	switch v := opt.(type) {
+// SetSockOptBool implements tcpip.Endpoint.SetSockOptBool.
+func (e *endpoint) SetSockOptBool(opt tcpip.SockOptBool, v bool) *tcpip.Error {
+	switch opt {
 	case tcpip.V6OnlyOption:
 		// We only recognize this option on v6 endpoints.
 		if e.NetProto != header.IPv6ProtocolNumber {
@@ -478,8 +473,20 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 			return tcpip.ErrInvalidEndpointState
 		}
 
-		e.v6only = v != 0
+		e.v6only = v
+	}
+
+	return nil
+}
 
+// SetSockOptInt implements tcpip.Endpoint.SetSockOptInt.
+func (e *endpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
+	return nil
+}
+
+// SetSockOpt implements tcpip.Endpoint.SetSockOpt.
+func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
+	switch v := opt.(type) {
 	case tcpip.TTLOption:
 		e.mu.Lock()
 		e.ttl = uint8(v)
@@ -660,6 +667,25 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 	return nil
 }
 
+// GetSockOptBool implements tcpip.Endpoint.GetSockOptBool.
+func (e *endpoint) GetSockOptBool(opt tcpip.SockOptBool) (bool, *tcpip.Error) {
+	switch opt {
+	case tcpip.V6OnlyOption:
+		// We only recognize this option on v6 endpoints.
+		if e.NetProto != header.IPv6ProtocolNumber {
+			return false, tcpip.ErrUnknownProtocolOption
+		}
+
+		e.mu.Lock()
+		v := e.v6only
+		e.mu.Unlock()
+
+		return v, nil
+	}
+
+	return false, tcpip.ErrUnknownProtocolOption
+}
+
 // GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
 func (e *endpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
 	switch opt {
@@ -695,22 +721,6 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 	case tcpip.ErrorOption:
 		return nil
 
-	case *tcpip.V6OnlyOption:
-		// We only recognize this option on v6 endpoints.
-		if e.NetProto != header.IPv6ProtocolNumber {
-			return tcpip.ErrUnknownProtocolOption
-		}
-
-		e.mu.Lock()
-		v := e.v6only
-		e.mu.Unlock()
-
-		*o = 0
-		if v {
-			*o = 1
-		}
-		return nil
-
 	case *tcpip.TTLOption:
 		e.mu.Lock()
 		*o = tcpip.TTLOption(e.ttl)
diff --git a/pkg/tcpip/transport/udp/udp_test.go b/pkg/tcpip/transport/udp/udp_test.go
index 65382b7f1..149fff999 100644
--- a/pkg/tcpip/transport/udp/udp_test.go
+++ b/pkg/tcpip/transport/udp/udp_test.go
@@ -335,7 +335,7 @@ func (c *testContext) createEndpointForFlow(flow testFlow) {
 
 	c.createEndpoint(flow.sockProto())
 	if flow.isV6Only() {
-		if err := c.ep.SetSockOpt(tcpip.V6OnlyOption(1)); err != nil {
+		if err := c.ep.SetSockOptBool(tcpip.V6OnlyOption, true); err != nil {
 			c.t.Fatalf("SetSockOpt failed: %v", err)
 		}
 	} else if flow.isBroadcast() {
-- 
cgit v1.2.3


From 1c2420146777de5b5727f69331b50be1b57a3351 Mon Sep 17 00:00:00 2001
From: Fabricio Voznika <fvoznika@google.com>
Date: Wed, 8 Jan 2020 15:40:00 -0800
Subject: Github bug reviver

For everyone's joy, this is a tool that reopens issues that
have been closed, but are still referenced by TODOs in the
code. The idea is to run it in Kokoro nightly. Kokoro changes
are coming up next.

PiperOrigin-RevId: 288789560
---
 WORKSPACE                                   |  21 +++
 go.mod                                      |   2 +
 go.sum                                      |   2 +
 tools/issue_reviver/BUILD                   |  12 ++
 tools/issue_reviver/github/BUILD            |  17 +++
 tools/issue_reviver/github/github.go        | 164 ++++++++++++++++++++++++
 tools/issue_reviver/main.go                 |  89 +++++++++++++
 tools/issue_reviver/reviver/BUILD           |  19 +++
 tools/issue_reviver/reviver/reviver.go      | 192 ++++++++++++++++++++++++++++
 tools/issue_reviver/reviver/reviver_test.go |  88 +++++++++++++
 10 files changed, 606 insertions(+)
 create mode 100644 tools/issue_reviver/BUILD
 create mode 100644 tools/issue_reviver/github/BUILD
 create mode 100644 tools/issue_reviver/github/github.go
 create mode 100644 tools/issue_reviver/main.go
 create mode 100644 tools/issue_reviver/reviver/BUILD
 create mode 100644 tools/issue_reviver/reviver/reviver.go
 create mode 100644 tools/issue_reviver/reviver/reviver_test.go

diff --git a/WORKSPACE b/WORKSPACE
index 4b5a3bfe2..e2afc073c 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -290,6 +290,27 @@ go_repository(
     version = "v1.3.1",
 )
 
+go_repository(
+    name = "com_github_google_go-github",
+    importpath = "github.com/google/go-github",
+    sum = "h1:N0LgJ1j65A7kfXrZnUDaYCs/Sf4rEjNlfyDHW9dolSY=",
+    version = "v17.0.0",
+)
+
+go_repository(
+    name = "org_golang_x_oauth2",
+    importpath = "golang.org/x/oauth2",
+    sum = "h1:pE8b58s1HRDMi8RDc79m0HISf9D4TzseP40cEA6IGfs=",
+    version = "v0.0.0-20191202225959-858c2ad4c8b6",
+)
+
+go_repository(
+    name = "com_github_google_go-querystring",
+    importpath = "github.com/google/go-querystring",
+    sum = "h1:Xkwi/a1rcvNg1PPYe5vI8GbeBY/jrVuDX5ASuANWTrk=",
+    version = "v1.0.0",
+)
+
 # System Call test dependencies.
 http_archive(
     name = "com_google_absl",
diff --git a/go.mod b/go.mod
index 304b8bf13..c4687ed02 100644
--- a/go.mod
+++ b/go.mod
@@ -9,6 +9,7 @@ require (
   github.com/golang/protobuf v1.3.1
   github.com/google/btree v1.0.0
   github.com/google/go-cmp v0.2.0
+  github.com/google/go-github/v28 v28.1.1
   github.com/google/subcommands v0.0.0-20190508160503-636abe8753b8
   github.com/google/uuid v0.0.0-20171129191014-dec09d789f3d
   github.com/kr/pty v1.1.1
@@ -17,5 +18,6 @@ require (
   github.com/vishvananda/netlink v1.0.1-0.20190318003149-adb577d4a45e
   github.com/vishvananda/netns v0.0.0-20171111001504-be1fbeda1936
   golang.org/x/net v0.0.0-20190311183353-d8887717615a
+  golang.org/x/oauth2 v0.0.0-20191202225959-858c2ad4c8b6
   golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a
 )
diff --git a/go.sum b/go.sum
index 7a0bc175a..434770beb 100644
--- a/go.sum
+++ b/go.sum
@@ -4,6 +4,7 @@ github.com/golang/mock v1.3.1/go.mod h1:sBzyDLLjw3U8JLTeZvSv8jJB+tU5PVekmnlKIyFU
 github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/google/btree v1.0.0/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
+github.com/google/go-github/v28 v28.1.1/go.mod h1:bsqJWQX05omyWVmc00nEUql9mhQyv38lDZ8kPZcQVoM=
 github.com/google/subcommands v0.0.0-20190508160503-636abe8753b8/go.mod h1:ZjhPrFU+Olkh9WazFPsl27BQ4UPiG37m3yTrtFlrHVk=
 github.com/google/uuid v0.0.0-20171129191014-dec09d789f3d/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
@@ -13,6 +14,7 @@ github.com/vishvananda/netlink v1.0.1-0.20190318003149-adb577d4a45e/go.mod h1:+S
 github.com/vishvananda/netns v0.0.0-20171111001504-be1fbeda1936/go.mod h1:ZjcWmFBXmLKZu9Nxj3WKYEafiSqer2rnvPr0en9UNpI=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/oauth2 v0.0.0-20191202225959-858c2ad4c8b6/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
diff --git a/tools/issue_reviver/BUILD b/tools/issue_reviver/BUILD
new file mode 100644
index 000000000..ee7ea11fd
--- /dev/null
+++ b/tools/issue_reviver/BUILD
@@ -0,0 +1,12 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_binary")
+
+package(licenses = ["notice"])
+
+go_binary(
+    name = "issue_reviver",
+    srcs = ["main.go"],
+    deps = [
+        "//tools/issue_reviver/github",
+        "//tools/issue_reviver/reviver",
+    ],
+)
diff --git a/tools/issue_reviver/github/BUILD b/tools/issue_reviver/github/BUILD
new file mode 100644
index 000000000..6da22ba1c
--- /dev/null
+++ b/tools/issue_reviver/github/BUILD
@@ -0,0 +1,17 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+package(licenses = ["notice"])
+
+go_library(
+    name = "github",
+    srcs = ["github.go"],
+    importpath = "gvisor.dev/gvisor/tools/issue_reviver/github",
+    visibility = [
+        "//tools/issue_reviver:__subpackages__",
+    ],
+    deps = [
+        "//tools/issue_reviver/reviver",
+        "@com_github_google_go-github//github:go_default_library",
+        "@org_golang_x_oauth2//:go_default_library",
+    ],
+)
diff --git a/tools/issue_reviver/github/github.go b/tools/issue_reviver/github/github.go
new file mode 100644
index 000000000..e07949c8f
--- /dev/null
+++ b/tools/issue_reviver/github/github.go
@@ -0,0 +1,164 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package github implements reviver.Bugger interface on top of Github issues.
+package github
+
+import (
+	"context"
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/google/go-github/github"
+	"golang.org/x/oauth2"
+	"gvisor.dev/gvisor/tools/issue_reviver/reviver"
+)
+
+// Bugger implements reviver.Bugger interface for github issues.
+type Bugger struct {
+	owner  string
+	repo   string
+	dryRun bool
+
+	client *github.Client
+	issues map[int]*github.Issue
+}
+
+// NewBugger creates a new Bugger.
+func NewBugger(token, owner, repo string, dryRun bool) (*Bugger, error) {
+	b := &Bugger{
+		owner:  owner,
+		repo:   repo,
+		dryRun: dryRun,
+		issues: map[int]*github.Issue{},
+	}
+	if err := b.load(token); err != nil {
+		return nil, err
+	}
+	return b, nil
+}
+
+func (b *Bugger) load(token string) error {
+	ctx := context.Background()
+	if len(token) == 0 {
+		fmt.Print("No OAUTH token provided, using unauthenticated account.\n")
+		b.client = github.NewClient(nil)
+	} else {
+		ts := oauth2.StaticTokenSource(
+			&oauth2.Token{AccessToken: token},
+		)
+		tc := oauth2.NewClient(ctx, ts)
+		b.client = github.NewClient(tc)
+	}
+
+	err := processAllPages(func(listOpts github.ListOptions) (*github.Response, error) {
+		opts := &github.IssueListByRepoOptions{State: "open", ListOptions: listOpts}
+		tmps, resp, err := b.client.Issues.ListByRepo(ctx, b.owner, b.repo, opts)
+		if err != nil {
+			return resp, err
+		}
+		for _, issue := range tmps {
+			b.issues[issue.GetNumber()] = issue
+		}
+		return resp, nil
+	})
+	if err != nil {
+		return err
+	}
+
+	fmt.Printf("Loaded %d issues from github.com/%s/%s\n", len(b.issues), b.owner, b.repo)
+	return nil
+}
+
+// Activate implements reviver.Bugger.
+func (b *Bugger) Activate(todo *reviver.Todo) (bool, error) {
+	const prefix = "gvisor.dev/issue/"
+
+	// First check if I can handle the TODO.
+	idStr := strings.TrimPrefix(todo.Issue, prefix)
+	if len(todo.Issue) == len(idStr) {
+		return false, nil
+	}
+
+	id, err := strconv.Atoi(idStr)
+	if err != nil {
+		return true, err
+	}
+
+	// Check against active issues cache.
+	if _, ok := b.issues[id]; ok {
+		fmt.Printf("%q is active: OK\n", todo.Issue)
+		return true, nil
+	}
+
+	fmt.Printf("%q is not active: reopening issue %d\n", todo.Issue, id)
+
+	// Format comment with TODO locations and search link.
+	comment := strings.Builder{}
+	fmt.Fprintln(&comment, "There are TODOs still referencing this issue:")
+	for _, l := range todo.Locations {
+		fmt.Fprintf(&comment,
+			"1. [%s:%d](https://github.com/%s/%s/blob/HEAD/%s#%d): %s\n",
+			l.File, l.Line, b.owner, b.repo, l.File, l.Line, l.Comment)
+	}
+	fmt.Fprintf(&comment,
+		"\n\nSearch [TODO](https://github.com/%s/%s/search?q=%%22%s%d%%22)", b.owner, b.repo, prefix, id)
+
+	if b.dryRun {
+		fmt.Printf("[dry-run: skipping change to issue %d]\n%s\n=======================\n", id, comment.String())
+		return true, nil
+	}
+
+	ctx := context.Background()
+	req := &github.IssueRequest{State: github.String("open")}
+	_, _, err = b.client.Issues.Edit(ctx, b.owner, b.repo, id, req)
+	if err != nil {
+		return true, fmt.Errorf("failed to reactivate issue %d: %v", id, err)
+	}
+
+	cmt := &github.IssueComment{
+		Body:      github.String(comment.String()),
+		Reactions: &github.Reactions{Confused: github.Int(1)},
+	}
+	if _, _, err := b.client.Issues.CreateComment(ctx, b.owner, b.repo, id, cmt); err != nil {
+		return true, fmt.Errorf("failed to add comment to issue %d: %v", id, err)
+	}
+
+	return true, nil
+}
+
+func processAllPages(fn func(github.ListOptions) (*github.Response, error)) error {
+	opts := github.ListOptions{PerPage: 1000}
+	for {
+		resp, err := fn(opts)
+		if err != nil {
+			if rateErr, ok := err.(*github.RateLimitError); ok {
+				duration := rateErr.Rate.Reset.Sub(time.Now())
+				if duration > 5*time.Minute {
+					return fmt.Errorf("Rate limited for too long: %v", duration)
+				}
+				fmt.Printf("Rate limited, sleeping for: %v\n", duration)
+				time.Sleep(duration)
+				continue
+			}
+			return err
+		}
+		if resp.NextPage == 0 {
+			return nil
+		}
+		opts.Page = resp.NextPage
+	}
+}
diff --git a/tools/issue_reviver/main.go b/tools/issue_reviver/main.go
new file mode 100644
index 000000000..4256f5a6c
--- /dev/null
+++ b/tools/issue_reviver/main.go
@@ -0,0 +1,89 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package main is the entry point for issue_reviver.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"gvisor.dev/gvisor/tools/issue_reviver/github"
+	"gvisor.dev/gvisor/tools/issue_reviver/reviver"
+)
+
+var (
+	owner     string
+	repo      string
+	tokenFile string
+	path      string
+	dryRun    bool
+)
+
+// Keep the options simple for now. Supports only a single path and repo.
+func init() {
+	flag.StringVar(&owner, "owner", "google", "Github project org/owner to look for issues")
+	flag.StringVar(&repo, "repo", "gvisor", "Github repo to look for issues")
+	flag.StringVar(&tokenFile, "oauth-token-file", "", "Path to file containing the OAUTH token to be used as credential to github")
+	flag.StringVar(&path, "path", "", "Path to scan for TODOs")
+	flag.BoolVar(&dryRun, "dry-run", false, "If set to true, no changes are made to issues")
+}
+
+func main() {
+	flag.Parse()
+
+	// Check for mandatory parameters.
+	if len(owner) == 0 {
+		fmt.Println("missing --owner option.")
+		flag.Usage()
+		os.Exit(1)
+	}
+	if len(repo) == 0 {
+		fmt.Println("missing --repo option.")
+		flag.Usage()
+		os.Exit(1)
+	}
+	if len(path) == 0 {
+		fmt.Println("missing --path option.")
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	// Token is passed as a file so it doesn't show up in command line arguments.
+	var token string
+	if len(tokenFile) != 0 {
+		bytes, err := ioutil.ReadFile(tokenFile)
+		if err != nil {
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+		token = string(bytes)
+	}
+
+	bugger, err := github.NewBugger(token, owner, repo, dryRun)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "Error getting github issues:", err)
+		os.Exit(1)
+	}
+	rev := reviver.New([]string{path}, []reviver.Bugger{bugger})
+	if errs := rev.Run(); len(errs) > 0 {
+		fmt.Fprintf(os.Stderr, "Encountered %d errors:\n", len(errs))
+		for _, err := range errs {
+			fmt.Fprintf(os.Stderr, "\t%v\n", err)
+		}
+		os.Exit(1)
+	}
+}
diff --git a/tools/issue_reviver/reviver/BUILD b/tools/issue_reviver/reviver/BUILD
new file mode 100644
index 000000000..2c3675977
--- /dev/null
+++ b/tools/issue_reviver/reviver/BUILD
@@ -0,0 +1,19 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+package(licenses = ["notice"])
+
+go_library(
+    name = "reviver",
+    srcs = ["reviver.go"],
+    importpath = "gvisor.dev/gvisor/tools/issue_reviver/reviver",
+    visibility = [
+        "//tools/issue_reviver:__subpackages__",
+    ],
+)
+
+go_test(
+    name = "reviver_test",
+    size = "small",
+    srcs = ["reviver_test.go"],
+    embed = [":reviver"],
+)
diff --git a/tools/issue_reviver/reviver/reviver.go b/tools/issue_reviver/reviver/reviver.go
new file mode 100644
index 000000000..682db0c01
--- /dev/null
+++ b/tools/issue_reviver/reviver/reviver.go
@@ -0,0 +1,192 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package reviver scans the code looking for TODOs and pass them to registered
+// Buggers to ensure TODOs point to active issues.
+package reviver
+
+import (
+	"bufio"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"regexp"
+	"sync"
+)
+
+// This is how a TODO looks like.
+var regexTodo = regexp.MustCompile(`(\/\/|#)\s*(TODO|FIXME)\(([a-zA-Z0-9.\/]+)\):\s*(.+)`)
+
+// Bugger interface is called for every TODO found in the code. If it can handle
+// the TODO, it must return true. If it returns false, the next Bugger is
+// called. If no Bugger handles the TODO, it's dropped on the floor.
+type Bugger interface {
+	Activate(todo *Todo) (bool, error)
+}
+
+// Location saves the location where the TODO was found.
+type Location struct {
+	Comment string
+	File    string
+	Line    uint
+}
+
+// Todo represents a unique TODO. There can be several TODOs pointing to the
+// same issue in the code. They are all grouped together.
+type Todo struct {
+	Issue     string
+	Locations []Location
+}
+
+// Reviver scans the given paths for TODOs and calls Buggers to handle them.
+type Reviver struct {
+	paths   []string
+	buggers []Bugger
+
+	mu    sync.Mutex
+	todos map[string]*Todo
+	errs  []error
+}
+
+// New create a new Reviver.
+func New(paths []string, buggers []Bugger) *Reviver {
+	return &Reviver{
+		paths:   paths,
+		buggers: buggers,
+		todos:   map[string]*Todo{},
+	}
+}
+
+// Run runs. It returns all errors found during processing, it doesn't stop
+// on errors.
+func (r *Reviver) Run() []error {
+	// Process each directory in parallel.
+	wg := sync.WaitGroup{}
+	for _, path := range r.paths {
+		wg.Add(1)
+		go func(path string) {
+			defer wg.Done()
+			r.processPath(path, &wg)
+		}(path)
+	}
+
+	wg.Wait()
+
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	fmt.Printf("Processing %d TODOs (%d errors)...\n", len(r.todos), len(r.errs))
+	dropped := 0
+	for _, todo := range r.todos {
+		ok, err := r.processTodo(todo)
+		if err != nil {
+			r.errs = append(r.errs, err)
+		}
+		if !ok {
+			dropped++
+		}
+	}
+	fmt.Printf("Processed %d TODOs, %d were skipped (%d errors)\n", len(r.todos)-dropped, dropped, len(r.errs))
+
+	return r.errs
+}
+
+func (r *Reviver) processPath(path string, wg *sync.WaitGroup) {
+	fmt.Printf("Processing dir %q\n", path)
+	fis, err := ioutil.ReadDir(path)
+	if err != nil {
+		r.addErr(fmt.Errorf("error processing dir %q: %v", path, err))
+		return
+	}
+
+	for _, fi := range fis {
+		childPath := filepath.Join(path, fi.Name())
+		switch {
+		case fi.Mode().IsDir():
+			wg.Add(1)
+			go func() {
+				defer wg.Done()
+				r.processPath(childPath, wg)
+			}()
+
+		case fi.Mode().IsRegular():
+			file, err := os.Open(childPath)
+			if err != nil {
+				r.addErr(err)
+				continue
+			}
+
+			scanner := bufio.NewScanner(file)
+			lineno := uint(0)
+			for scanner.Scan() {
+				lineno++
+				line := scanner.Text()
+				if todo := r.processLine(line, childPath, lineno); todo != nil {
+					r.addTodo(todo)
+				}
+			}
+		}
+	}
+}
+
+func (r *Reviver) processLine(line, path string, lineno uint) *Todo {
+	matches := regexTodo.FindStringSubmatch(line)
+	if matches == nil {
+		return nil
+	}
+	if len(matches) != 5 {
+		panic(fmt.Sprintf("regex returned wrong matches for %q: %v", line, matches))
+	}
+	return &Todo{
+		Issue: matches[3],
+		Locations: []Location{
+			{
+				File:    path,
+				Line:    lineno,
+				Comment: matches[4],
+			},
+		},
+	}
+}
+
+func (r *Reviver) addTodo(newTodo *Todo) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	if todo := r.todos[newTodo.Issue]; todo == nil {
+		r.todos[newTodo.Issue] = newTodo
+	} else {
+		todo.Locations = append(todo.Locations, newTodo.Locations...)
+	}
+}
+
+func (r *Reviver) addErr(err error) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	r.errs = append(r.errs, err)
+}
+
+func (r *Reviver) processTodo(todo *Todo) (bool, error) {
+	for _, bugger := range r.buggers {
+		ok, err := bugger.Activate(todo)
+		if err != nil {
+			return false, err
+		}
+		if ok {
+			return true, nil
+		}
+	}
+	return false, nil
+}
diff --git a/tools/issue_reviver/reviver/reviver_test.go b/tools/issue_reviver/reviver/reviver_test.go
new file mode 100644
index 000000000..a9fb1f9f1
--- /dev/null
+++ b/tools/issue_reviver/reviver/reviver_test.go
@@ -0,0 +1,88 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package reviver
+
+import (
+	"testing"
+)
+
+func TestProcessLine(t *testing.T) {
+	for _, tc := range []struct {
+		line string
+		want *Todo
+	}{
+		{
+			line: "// TODO(foobar.com/issue/123): comment, bla. blabla.",
+			want: &Todo{
+				Issue: "foobar.com/issue/123",
+				Locations: []Location{
+					{Comment: "comment, bla. blabla."},
+				},
+			},
+		},
+		{
+			line: "// FIXME(b/123): internal bug",
+			want: &Todo{
+				Issue: "b/123",
+				Locations: []Location{
+					{Comment: "internal bug"},
+				},
+			},
+		},
+		{
+			line: "TODO(issue): not todo",
+		},
+		{
+			line: "FIXME(issue): not todo",
+		},
+		{
+			line: "// TODO (issue): not todo",
+		},
+		{
+			line: "// TODO(issue) not todo",
+		},
+		{
+			line: "// todo(issue): not todo",
+		},
+		{
+			line: "// TODO(issue):",
+		},
+	} {
+		t.Logf("Testing: %s", tc.line)
+		r := Reviver{}
+		got := r.processLine(tc.line, "test", 0)
+		if got == nil {
+			if tc.want != nil {
+				t.Errorf("failed to process line, want: %+v", tc.want)
+			}
+		} else {
+			if tc.want == nil {
+				t.Errorf("expected error, got: %+v", got)
+				continue
+			}
+			if got.Issue != tc.want.Issue {
+				t.Errorf("wrong issue, got: %v, want: %v", got.Issue, tc.want.Issue)
+			}
+			if len(got.Locations) != len(tc.want.Locations) {
+				t.Errorf("wrong number of locations, got: %v, want: %v, locations: %+v", len(got.Locations), len(tc.want.Locations), got.Locations)
+			}
+			for i, wantLoc := range tc.want.Locations {
+				if got.Locations[i].Comment != wantLoc.Comment {
+					t.Errorf("wrong comment, got: %v, want: %v", got.Locations[i].Comment, wantLoc.Comment)
+				}
+			}
+		}
+	}
+}
-- 
cgit v1.2.3


From b3ae8a62cfdf13821d35467d4150ed983ac556f1 Mon Sep 17 00:00:00 2001
From: Ting-Yu Wang <anivia@google.com>
Date: Wed, 8 Jan 2020 16:29:12 -0800
Subject: Fix slice bounds out of range panic in parsing socket control
 message.

Panic found by syzakller.

PiperOrigin-RevId: 288799046
---
 pkg/sentry/socket/control/control.go     |  6 ++++++
 test/syscalls/linux/socket_ip_unbound.cc | 33 ++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/pkg/sentry/socket/control/control.go b/pkg/sentry/socket/control/control.go
index af1a4e95f..4301b697c 100644
--- a/pkg/sentry/socket/control/control.go
+++ b/pkg/sentry/socket/control/control.go
@@ -471,6 +471,9 @@ func Parse(t *kernel.Task, socketOrEndpoint interface{}, buf []byte) (socket.Con
 		case linux.SOL_IP:
 			switch h.Type {
 			case linux.IP_TOS:
+				if length < linux.SizeOfControlMessageTOS {
+					return socket.ControlMessages{}, syserror.EINVAL
+				}
 				cmsgs.IP.HasTOS = true
 				binary.Unmarshal(buf[i:i+linux.SizeOfControlMessageTOS], usermem.ByteOrder, &cmsgs.IP.TOS)
 				i += AlignUp(length, width)
@@ -481,6 +484,9 @@ func Parse(t *kernel.Task, socketOrEndpoint interface{}, buf []byte) (socket.Con
 		case linux.SOL_IPV6:
 			switch h.Type {
 			case linux.IPV6_TCLASS:
+				if length < linux.SizeOfControlMessageTClass {
+					return socket.ControlMessages{}, syserror.EINVAL
+				}
 				cmsgs.IP.HasTClass = true
 				binary.Unmarshal(buf[i:i+linux.SizeOfControlMessageTClass], usermem.ByteOrder, &cmsgs.IP.TClass)
 				i += AlignUp(length, width)
diff --git a/test/syscalls/linux/socket_ip_unbound.cc b/test/syscalls/linux/socket_ip_unbound.cc
index b6754111f..ca597e267 100644
--- a/test/syscalls/linux/socket_ip_unbound.cc
+++ b/test/syscalls/linux/socket_ip_unbound.cc
@@ -129,6 +129,7 @@ TEST_P(IPUnboundSocketTest, InvalidNegativeTtl) {
 struct TOSOption {
   int level;
   int option;
+  int cmsg_level;
 };
 
 constexpr int INET_ECN_MASK = 3;
@@ -139,10 +140,12 @@ static TOSOption GetTOSOption(int domain) {
     case AF_INET:
       opt.level = IPPROTO_IP;
       opt.option = IP_TOS;
+      opt.cmsg_level = SOL_IP;
       break;
     case AF_INET6:
       opt.level = IPPROTO_IPV6;
       opt.option = IPV6_TCLASS;
+      opt.cmsg_level = SOL_IPV6;
       break;
   }
   return opt;
@@ -386,6 +389,36 @@ TEST_P(IPUnboundSocketTest, NullTOS) {
               SyscallFailsWithErrno(EFAULT));
 }
 
+TEST_P(IPUnboundSocketTest, InsufficientBufferTOS) {
+  SKIP_IF(GetParam().protocol == IPPROTO_TCP);
+
+  auto socket = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
+  TOSOption t = GetTOSOption(GetParam().domain);
+
+  in_addr addr4;
+  in6_addr addr6;
+  ASSERT_THAT(inet_pton(AF_INET, "127.0.0.1", &addr4), ::testing::Eq(1));
+  ASSERT_THAT(inet_pton(AF_INET6, "fe80::", &addr6), ::testing::Eq(1));
+
+  cmsghdr cmsg = {};
+  cmsg.cmsg_len = sizeof(cmsg);
+  cmsg.cmsg_level = t.cmsg_level;
+  cmsg.cmsg_type = t.option;
+
+  msghdr msg = {};
+  msg.msg_control = &cmsg;
+  msg.msg_controllen = sizeof(cmsg);
+  if (GetParam().domain == AF_INET) {
+    msg.msg_name = &addr4;
+    msg.msg_namelen = sizeof(addr4);
+  } else {
+    msg.msg_name = &addr6;
+    msg.msg_namelen = sizeof(addr6);
+  }
+
+  EXPECT_THAT(sendmsg(socket->get(), &msg, 0), SyscallFailsWithErrno(EINVAL));
+}
+
 INSTANTIATE_TEST_SUITE_P(
     IPUnboundSockets, IPUnboundSocketTest,
     ::testing::ValuesIn(VecCat<SocketKind>(VecCat<SocketKind>(
-- 
cgit v1.2.3


From 565b64148314018e1234196182b55c4f01772e77 Mon Sep 17 00:00:00 2001
From: Dean Deng <deandeng@google.com>
Date: Wed, 8 Jan 2020 16:32:50 -0800
Subject: Define sizes for extent headers and entries separately to improve
 clarity.

PiperOrigin-RevId: 288799694
---
 pkg/sentry/fsimpl/ext/disklayout/extent.go      | 10 +++++++---
 pkg/sentry/fsimpl/ext/disklayout/extent_test.go |  6 +++---
 pkg/sentry/fsimpl/ext/extent_file.go            |  8 ++++----
 3 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/pkg/sentry/fsimpl/ext/disklayout/extent.go b/pkg/sentry/fsimpl/ext/disklayout/extent.go
index 567523d32..4110649ab 100644
--- a/pkg/sentry/fsimpl/ext/disklayout/extent.go
+++ b/pkg/sentry/fsimpl/ext/disklayout/extent.go
@@ -29,8 +29,12 @@ package disklayout
 //       byte (i * sb.BlockSize()) to ((i+1) * sb.BlockSize()).
 
 const (
-	// ExtentStructsSize is the size of all the three extent on-disk structs.
-	ExtentStructsSize = 12
+	// ExtentHeaderSize is the size of the header of an extent tree node.
+	ExtentHeaderSize = 12
+
+	// ExtentEntrySize is the size of an entry in an extent tree node.
+	// This size is the same for both leaf and internal nodes.
+	ExtentEntrySize = 12
 
 	// ExtentMagic is the magic number which must be present in the header.
 	ExtentMagic = 0xf30a
@@ -57,7 +61,7 @@ type ExtentNode struct {
 	Entries []ExtentEntryPair
 }
 
-// ExtentEntry reprsents an extent tree node entry. The entry can either be
+// ExtentEntry represents an extent tree node entry. The entry can either be
 // an ExtentIdx or Extent itself. This exists to simplify navigation logic.
 type ExtentEntry interface {
 	// FileBlock returns the first file block number covered by this entry.
diff --git a/pkg/sentry/fsimpl/ext/disklayout/extent_test.go b/pkg/sentry/fsimpl/ext/disklayout/extent_test.go
index b0fad9b71..8762b90db 100644
--- a/pkg/sentry/fsimpl/ext/disklayout/extent_test.go
+++ b/pkg/sentry/fsimpl/ext/disklayout/extent_test.go
@@ -21,7 +21,7 @@ import (
 // TestExtentSize tests that the extent structs are of the correct
 // size.
 func TestExtentSize(t *testing.T) {
-	assertSize(t, ExtentHeader{}, ExtentStructsSize)
-	assertSize(t, ExtentIdx{}, ExtentStructsSize)
-	assertSize(t, Extent{}, ExtentStructsSize)
+	assertSize(t, ExtentHeader{}, ExtentHeaderSize)
+	assertSize(t, ExtentIdx{}, ExtentEntrySize)
+	assertSize(t, Extent{}, ExtentEntrySize)
 }
diff --git a/pkg/sentry/fsimpl/ext/extent_file.go b/pkg/sentry/fsimpl/ext/extent_file.go
index 3d3ebaca6..11dcc0346 100644
--- a/pkg/sentry/fsimpl/ext/extent_file.go
+++ b/pkg/sentry/fsimpl/ext/extent_file.go
@@ -57,7 +57,7 @@ func newExtentFile(regFile regularFile) (*extentFile, error) {
 func (f *extentFile) buildExtTree() error {
 	rootNodeData := f.regFile.inode.diskInode.Data()
 
-	binary.Unmarshal(rootNodeData[:disklayout.ExtentStructsSize], binary.LittleEndian, &f.root.Header)
+	binary.Unmarshal(rootNodeData[:disklayout.ExtentHeaderSize], binary.LittleEndian, &f.root.Header)
 
 	// Root node can not have more than 4 entries: 60 bytes = 1 header + 4 entries.
 	if f.root.Header.NumEntries > 4 {
@@ -67,7 +67,7 @@ func (f *extentFile) buildExtTree() error {
 	}
 
 	f.root.Entries = make([]disklayout.ExtentEntryPair, f.root.Header.NumEntries)
-	for i, off := uint16(0), disklayout.ExtentStructsSize; i < f.root.Header.NumEntries; i, off = i+1, off+disklayout.ExtentStructsSize {
+	for i, off := uint16(0), disklayout.ExtentEntrySize; i < f.root.Header.NumEntries; i, off = i+1, off+disklayout.ExtentEntrySize {
 		var curEntry disklayout.ExtentEntry
 		if f.root.Header.Height == 0 {
 			// Leaf node.
@@ -76,7 +76,7 @@ func (f *extentFile) buildExtTree() error {
 			// Internal node.
 			curEntry = &disklayout.ExtentIdx{}
 		}
-		binary.Unmarshal(rootNodeData[off:off+disklayout.ExtentStructsSize], binary.LittleEndian, curEntry)
+		binary.Unmarshal(rootNodeData[off:off+disklayout.ExtentEntrySize], binary.LittleEndian, curEntry)
 		f.root.Entries[i].Entry = curEntry
 	}
 
@@ -105,7 +105,7 @@ func (f *extentFile) buildExtTreeFromDisk(entry disklayout.ExtentEntry) (*diskla
 	}
 
 	entries := make([]disklayout.ExtentEntryPair, header.NumEntries)
-	for i, off := uint16(0), off+disklayout.ExtentStructsSize; i < header.NumEntries; i, off = i+1, off+disklayout.ExtentStructsSize {
+	for i, off := uint16(0), off+disklayout.ExtentEntrySize; i < header.NumEntries; i, off = i+1, off+disklayout.ExtentEntrySize {
 		var curEntry disklayout.ExtentEntry
 		if header.Height == 0 {
 			// Leaf node.
-- 
cgit v1.2.3


From fbb2c008e26a7e9d860f6cbf796ea7c375858502 Mon Sep 17 00:00:00 2001
From: Ian Lewis <ianlewis@google.com>
Date: Wed, 8 Jan 2020 16:35:43 -0800
Subject: Return correct length with MSG_TRUNC for unix sockets.

This change calls a new Truncate method on the EndpointReader in RecvMsg for
both netlink and unix sockets.  This allows readers such as sockets to peek at
the length of data without actually reading it to a buffer.

Fixes #993 #1240

PiperOrigin-RevId: 288800167
---
 pkg/sentry/socket/netlink/BUILD                   |   1 -
 pkg/sentry/socket/netlink/socket.go               |  29 +++---
 pkg/sentry/socket/unix/io.go                      |  13 +++
 pkg/sentry/socket/unix/unix.go                    |  23 ++++-
 test/syscalls/linux/BUILD                         |   1 -
 test/syscalls/linux/socket_non_stream.cc          | 113 +++++++++++++++++++++-
 test/syscalls/linux/socket_non_stream_blocking.cc |  37 +++++++
 test/syscalls/linux/socket_stream.cc              |  55 ++++++++++-
 8 files changed, 250 insertions(+), 22 deletions(-)

diff --git a/pkg/sentry/socket/netlink/BUILD b/pkg/sentry/socket/netlink/BUILD
index 79589e3c8..136821963 100644
--- a/pkg/sentry/socket/netlink/BUILD
+++ b/pkg/sentry/socket/netlink/BUILD
@@ -22,7 +22,6 @@ go_library(
         "//pkg/sentry/kernel",
         "//pkg/sentry/kernel/auth",
         "//pkg/sentry/kernel/time",
-        "//pkg/sentry/safemem",
         "//pkg/sentry/socket",
         "//pkg/sentry/socket/netlink/port",
         "//pkg/sentry/socket/unix",
diff --git a/pkg/sentry/socket/netlink/socket.go b/pkg/sentry/socket/netlink/socket.go
index 4a1b87a9a..d2e3644a6 100644
--- a/pkg/sentry/socket/netlink/socket.go
+++ b/pkg/sentry/socket/netlink/socket.go
@@ -29,7 +29,6 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
-	"gvisor.dev/gvisor/pkg/sentry/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/socket"
 	"gvisor.dev/gvisor/pkg/sentry/socket/netlink/port"
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix"
@@ -500,29 +499,29 @@ func (s *Socket) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags int, have
 	trunc := flags&linux.MSG_TRUNC != 0
 
 	r := unix.EndpointReader{
+		Ctx:      t,
 		Endpoint: s.ep,
 		Peek:     flags&linux.MSG_PEEK != 0,
 	}
 
+	doRead := func() (int64, error) {
+		return dst.CopyOutFrom(t, &r)
+	}
+
 	// If MSG_TRUNC is set with a zero byte destination then we still need
 	// to read the message and discard it, or in the case where MSG_PEEK is
 	// set, leave it be. In both cases the full message length must be
-	// returned. However, the memory manager for the destination will not read
-	// the endpoint if the destination is zero length.
-	//
-	// In order for the endpoint to be read when the destination size is zero,
-	// we must cause a read of the endpoint by using a separate fake zero
-	// length block sequence and calling the EndpointReader directly.
+	// returned.
 	if trunc && dst.Addrs.NumBytes() == 0 {
-		// Perform a read to a zero byte block sequence. We can ignore the
-		// original destination since it was zero bytes. The length returned by
-		// ReadToBlocks is ignored and we return the full message length to comply
-		// with MSG_TRUNC.
-		_, err := r.ReadToBlocks(safemem.BlockSeqOf(safemem.BlockFromSafeSlice(make([]byte, 0))))
-		return int(r.MsgSize), linux.MSG_TRUNC, from, fromLen, socket.ControlMessages{}, syserr.FromError(err)
+		doRead = func() (int64, error) {
+			err := r.Truncate()
+			// Always return zero for bytes read since the destination size is
+			// zero.
+			return 0, err
+		}
 	}
 
-	if n, err := dst.CopyOutFrom(t, &r); err != syserror.ErrWouldBlock || flags&linux.MSG_DONTWAIT != 0 {
+	if n, err := doRead(); err != syserror.ErrWouldBlock || flags&linux.MSG_DONTWAIT != 0 {
 		var mflags int
 		if n < int64(r.MsgSize) {
 			mflags |= linux.MSG_TRUNC
@@ -540,7 +539,7 @@ func (s *Socket) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags int, have
 	defer s.EventUnregister(&e)
 
 	for {
-		if n, err := dst.CopyOutFrom(t, &r); err != syserror.ErrWouldBlock {
+		if n, err := doRead(); err != syserror.ErrWouldBlock {
 			var mflags int
 			if n < int64(r.MsgSize) {
 				mflags |= linux.MSG_TRUNC
diff --git a/pkg/sentry/socket/unix/io.go b/pkg/sentry/socket/unix/io.go
index 2ec1a662d..2447f24ef 100644
--- a/pkg/sentry/socket/unix/io.go
+++ b/pkg/sentry/socket/unix/io.go
@@ -83,6 +83,19 @@ type EndpointReader struct {
 	ControlTrunc bool
 }
 
+// Truncate calls RecvMsg on the endpoint without writing to a destination.
+func (r *EndpointReader) Truncate() error {
+	// Ignore bytes read since it will always be zero.
+	_, ms, c, ct, err := r.Endpoint.RecvMsg(r.Ctx, [][]byte{}, r.Creds, r.NumRights, r.Peek, r.From)
+	r.Control = c
+	r.ControlTrunc = ct
+	r.MsgSize = ms
+	if err != nil {
+		return err.ToError()
+	}
+	return nil
+}
+
 // ReadToBlocks implements safemem.Reader.ReadToBlocks.
 func (r *EndpointReader) ReadToBlocks(dsts safemem.BlockSeq) (uint64, error) {
 	return safemem.FromVecReaderFunc{func(bufs [][]byte) (int64, error) {
diff --git a/pkg/sentry/socket/unix/unix.go b/pkg/sentry/socket/unix/unix.go
index 885758054..91effe89a 100644
--- a/pkg/sentry/socket/unix/unix.go
+++ b/pkg/sentry/socket/unix/unix.go
@@ -544,8 +544,27 @@ func (s *SocketOperations) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags
 	if senderRequested {
 		r.From = &tcpip.FullAddress{}
 	}
+
+	doRead := func() (int64, error) {
+		return dst.CopyOutFrom(t, &r)
+	}
+
+	// If MSG_TRUNC is set with a zero byte destination then we still need
+	// to read the message and discard it, or in the case where MSG_PEEK is
+	// set, leave it be. In both cases the full message length must be
+	// returned.
+	if trunc && dst.Addrs.NumBytes() == 0 {
+		doRead = func() (int64, error) {
+			err := r.Truncate()
+			// Always return zero for bytes read since the destination size is
+			// zero.
+			return 0, err
+		}
+
+	}
+
 	var total int64
-	if n, err := dst.CopyOutFrom(t, &r); err != syserror.ErrWouldBlock || dontWait {
+	if n, err := doRead(); err != syserror.ErrWouldBlock || dontWait {
 		var from linux.SockAddr
 		var fromLen uint32
 		if r.From != nil && len([]byte(r.From.Addr)) != 0 {
@@ -580,7 +599,7 @@ func (s *SocketOperations) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags
 	defer s.EventUnregister(&e)
 
 	for {
-		if n, err := dst.CopyOutFrom(t, &r); err != syserror.ErrWouldBlock {
+		if n, err := doRead(); err != syserror.ErrWouldBlock {
 			var from linux.SockAddr
 			var fromLen uint32
 			if r.From != nil {
diff --git a/test/syscalls/linux/BUILD b/test/syscalls/linux/BUILD
index 064ce8429..ce8abe217 100644
--- a/test/syscalls/linux/BUILD
+++ b/test/syscalls/linux/BUILD
@@ -2888,7 +2888,6 @@ cc_library(
         ":unix_domain_socket_test_util",
         "//test/util:test_util",
         "//test/util:thread_util",
-        "//test/util:timer_util",
         "@com_google_absl//absl/time",
         "@com_google_googletest//:gtest",
     ],
diff --git a/test/syscalls/linux/socket_non_stream.cc b/test/syscalls/linux/socket_non_stream.cc
index d91c5ed39..c61817f14 100644
--- a/test/syscalls/linux/socket_non_stream.cc
+++ b/test/syscalls/linux/socket_non_stream.cc
@@ -113,7 +113,7 @@ TEST_P(NonStreamSocketPairTest, RecvmsgMsghdrFlagMsgTrunc) {
   EXPECT_EQ(0, memcmp(received_data, sent_data, sizeof(received_data)));
 
   // Check that msghdr flags were updated.
-  EXPECT_EQ(msg.msg_flags, MSG_TRUNC);
+  EXPECT_EQ(msg.msg_flags & MSG_TRUNC, MSG_TRUNC);
 }
 
 // Stream sockets allow data sent with multiple sends to be peeked at in a
@@ -193,7 +193,7 @@ TEST_P(NonStreamSocketPairTest, MsgTruncTruncationRecvmsgMsghdrFlagMsgTrunc) {
   EXPECT_EQ(0, memcmp(received_data, sent_data, sizeof(received_data)));
 
   // Check that msghdr flags were updated.
-  EXPECT_EQ(msg.msg_flags, MSG_TRUNC);
+  EXPECT_EQ(msg.msg_flags & MSG_TRUNC, MSG_TRUNC);
 }
 
 TEST_P(NonStreamSocketPairTest, MsgTruncSameSize) {
@@ -224,5 +224,114 @@ TEST_P(NonStreamSocketPairTest, MsgTruncNotFull) {
   EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));
 }
 
+// This test tests reading from a socket with MSG_TRUNC and a zero length
+// receive buffer. The user should be able to get the message length.
+TEST_P(NonStreamSocketPairTest, RecvmsgMsgTruncZeroLen) {
+  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+  char sent_data[10];
+  RandomizeBuffer(sent_data, sizeof(sent_data));
+  ASSERT_THAT(
+      RetryEINTR(send)(sockets->first_fd(), sent_data, sizeof(sent_data), 0),
+      SyscallSucceedsWithValue(sizeof(sent_data)));
+
+  // The receive buffer is of zero length.
+  char received_data[0] = {};
+
+  struct iovec iov;
+  iov.iov_base = received_data;
+  iov.iov_len = sizeof(received_data);
+  struct msghdr msg = {};
+  msg.msg_flags = -1;
+  msg.msg_iov = &iov;
+  msg.msg_iovlen = 1;
+
+  // The syscall succeeds returning the full size of the message on the socket.
+  ASSERT_THAT(RetryEINTR(recvmsg)(sockets->second_fd(), &msg, MSG_TRUNC),
+              SyscallSucceedsWithValue(sizeof(sent_data)));
+
+  // Check that MSG_TRUNC is set on msghdr flags.
+  EXPECT_EQ(msg.msg_flags & MSG_TRUNC, MSG_TRUNC);
+}
+
+// This test tests reading from a socket with MSG_TRUNC | MSG_PEEK and a zero
+// length receive buffer. The user should be able to get the message length
+// without reading data off the socket.
+TEST_P(NonStreamSocketPairTest, RecvmsgMsgTruncMsgPeekZeroLen) {
+  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+  char sent_data[10];
+  RandomizeBuffer(sent_data, sizeof(sent_data));
+  ASSERT_THAT(
+      RetryEINTR(send)(sockets->first_fd(), sent_data, sizeof(sent_data), 0),
+      SyscallSucceedsWithValue(sizeof(sent_data)));
+
+  // The receive buffer is of zero length.
+  char peek_data[0] = {};
+
+  struct iovec peek_iov;
+  peek_iov.iov_base = peek_data;
+  peek_iov.iov_len = sizeof(peek_data);
+  struct msghdr peek_msg = {};
+  peek_msg.msg_flags = -1;
+  peek_msg.msg_iov = &peek_iov;
+  peek_msg.msg_iovlen = 1;
+
+  // The syscall succeeds returning the full size of the message on the socket.
+  ASSERT_THAT(RetryEINTR(recvmsg)(sockets->second_fd(), &peek_msg,
+                                  MSG_TRUNC | MSG_PEEK),
+              SyscallSucceedsWithValue(sizeof(sent_data)));
+
+  // Check that MSG_TRUNC is set on msghdr flags because the receive buffer is
+  // smaller than the message size.
+  EXPECT_EQ(peek_msg.msg_flags & MSG_TRUNC, MSG_TRUNC);
+
+  char received_data[sizeof(sent_data)] = {};
+
+  struct iovec received_iov;
+  received_iov.iov_base = received_data;
+  received_iov.iov_len = sizeof(received_data);
+  struct msghdr received_msg = {};
+  received_msg.msg_flags = -1;
+  received_msg.msg_iov = &received_iov;
+  received_msg.msg_iovlen = 1;
+
+  // Next we can read the actual data.
+  ASSERT_THAT(
+      RetryEINTR(recvmsg)(sockets->second_fd(), &received_msg, MSG_TRUNC),
+      SyscallSucceedsWithValue(sizeof(sent_data)));
+
+  EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));
+
+  // Check that MSG_TRUNC is not set on msghdr flags because we read the whole
+  // message.
+  EXPECT_EQ(received_msg.msg_flags & MSG_TRUNC, 0);
+}
+
+// This test tests reading from a socket with MSG_TRUNC | MSG_PEEK and a zero
+// length receive buffer and MSG_DONTWAIT. The user should be able to get an
+// EAGAIN or EWOULDBLOCK error response.
+TEST_P(NonStreamSocketPairTest, RecvmsgTruncPeekDontwaitZeroLen) {
+  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+  // NOTE: We don't send any data on the socket.
+
+  // The receive buffer is of zero length.
+  char peek_data[0] = {};
+
+  struct iovec peek_iov;
+  peek_iov.iov_base = peek_data;
+  peek_iov.iov_len = sizeof(peek_data);
+  struct msghdr peek_msg = {};
+  peek_msg.msg_flags = -1;
+  peek_msg.msg_iov = &peek_iov;
+  peek_msg.msg_iovlen = 1;
+
+  // recvmsg fails with EAGAIN because no data is available on the socket.
+  ASSERT_THAT(RetryEINTR(recvmsg)(sockets->second_fd(), &peek_msg,
+                                  MSG_TRUNC | MSG_PEEK | MSG_DONTWAIT),
+              SyscallFailsWithErrno(EAGAIN));
+}
+
 }  // namespace testing
 }  // namespace gvisor
diff --git a/test/syscalls/linux/socket_non_stream_blocking.cc b/test/syscalls/linux/socket_non_stream_blocking.cc
index 62d87c1af..b052f6e61 100644
--- a/test/syscalls/linux/socket_non_stream_blocking.cc
+++ b/test/syscalls/linux/socket_non_stream_blocking.cc
@@ -25,6 +25,7 @@
 #include "test/syscalls/linux/socket_test_util.h"
 #include "test/syscalls/linux/unix_domain_socket_test_util.h"
 #include "test/util/test_util.h"
+#include "test/util/thread_util.h"
 
 namespace gvisor {
 namespace testing {
@@ -44,5 +45,41 @@ TEST_P(BlockingNonStreamSocketPairTest, RecvLessThanBufferWaitAll) {
               SyscallSucceedsWithValue(sizeof(sent_data)));
 }
 
+// This test tests reading from a socket with MSG_TRUNC | MSG_PEEK and a zero
+// length receive buffer and MSG_DONTWAIT. The recvmsg call should block on
+// reading the data.
+TEST_P(BlockingNonStreamSocketPairTest,
+       RecvmsgTruncPeekDontwaitZeroLenBlocking) {
+  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+  // NOTE: We don't initially send any data on the socket.
+  const int data_size = 10;
+  char sent_data[data_size];
+  RandomizeBuffer(sent_data, data_size);
+
+  // The receive buffer is of zero length.
+  char peek_data[0] = {};
+
+  struct iovec peek_iov;
+  peek_iov.iov_base = peek_data;
+  peek_iov.iov_len = sizeof(peek_data);
+  struct msghdr peek_msg = {};
+  peek_msg.msg_flags = -1;
+  peek_msg.msg_iov = &peek_iov;
+  peek_msg.msg_iovlen = 1;
+
+  ScopedThread t([&]() {
+    // The syscall succeeds returning the full size of the message on the
+    // socket. This should block until there is data on the socket.
+    ASSERT_THAT(RetryEINTR(recvmsg)(sockets->second_fd(), &peek_msg,
+                                    MSG_TRUNC | MSG_PEEK),
+                SyscallSucceedsWithValue(data_size));
+  });
+
+  absl::SleepFor(absl::Seconds(1));
+  ASSERT_THAT(RetryEINTR(send)(sockets->first_fd(), sent_data, data_size, 0),
+              SyscallSucceedsWithValue(data_size));
+}
+
 }  // namespace testing
 }  // namespace gvisor
diff --git a/test/syscalls/linux/socket_stream.cc b/test/syscalls/linux/socket_stream.cc
index 346443f96..6522b2e01 100644
--- a/test/syscalls/linux/socket_stream.cc
+++ b/test/syscalls/linux/socket_stream.cc
@@ -104,7 +104,60 @@ TEST_P(StreamSocketPairTest, RecvmsgMsghdrFlagsNoMsgTrunc) {
   EXPECT_EQ(0, memcmp(received_data, sent_data, sizeof(received_data)));
 
   // Check that msghdr flags were cleared (MSG_TRUNC was not set).
-  EXPECT_EQ(msg.msg_flags, 0);
+  ASSERT_EQ(msg.msg_flags & MSG_TRUNC, 0);
+}
+
+TEST_P(StreamSocketPairTest, RecvmsgTruncZeroLen) {
+  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+  char sent_data[10];
+  RandomizeBuffer(sent_data, sizeof(sent_data));
+  ASSERT_THAT(
+      RetryEINTR(send)(sockets->first_fd(), sent_data, sizeof(sent_data), 0),
+      SyscallSucceedsWithValue(sizeof(sent_data)));
+
+  char received_data[0] = {};
+
+  struct iovec iov;
+  iov.iov_base = received_data;
+  iov.iov_len = sizeof(received_data);
+  struct msghdr msg = {};
+  msg.msg_flags = -1;
+  msg.msg_iov = &iov;
+  msg.msg_iovlen = 1;
+
+  ASSERT_THAT(RetryEINTR(recvmsg)(sockets->second_fd(), &msg, MSG_TRUNC),
+              SyscallSucceedsWithValue(0));
+
+  // Check that msghdr flags were cleared (MSG_TRUNC was not set).
+  ASSERT_EQ(msg.msg_flags & MSG_TRUNC, 0);
+}
+
+TEST_P(StreamSocketPairTest, RecvmsgTruncPeekZeroLen) {
+  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+  char sent_data[10];
+  RandomizeBuffer(sent_data, sizeof(sent_data));
+  ASSERT_THAT(
+      RetryEINTR(send)(sockets->first_fd(), sent_data, sizeof(sent_data), 0),
+      SyscallSucceedsWithValue(sizeof(sent_data)));
+
+  char received_data[0] = {};
+
+  struct iovec iov;
+  iov.iov_base = received_data;
+  iov.iov_len = sizeof(received_data);
+  struct msghdr msg = {};
+  msg.msg_flags = -1;
+  msg.msg_iov = &iov;
+  msg.msg_iovlen = 1;
+
+  ASSERT_THAT(
+      RetryEINTR(recvmsg)(sockets->second_fd(), &msg, MSG_TRUNC | MSG_PEEK),
+      SyscallSucceedsWithValue(0));
+
+  // Check that msghdr flags were cleared (MSG_TRUNC was not set).
+  ASSERT_EQ(msg.msg_flags & MSG_TRUNC, 0);
 }
 
 TEST_P(StreamSocketPairTest, MsgTrunc) {
-- 
cgit v1.2.3


From d057871f410088fe6825b1dde695f015e36abf73 Mon Sep 17 00:00:00 2001
From: Ghanan Gowripalan <ghanan@google.com>
Date: Wed, 8 Jan 2020 17:19:35 -0800
Subject: CancellableTimer to encapsulate the work of safely stopping timers

Add a new CancellableTimer type to encapsulate the work of safely stopping
timers when it fires at the same time some "related work" is being handled. The
term "related work" is some work that needs to be done while having obtained
some common lock (L).

Example: Say we have an invalidation timer that may be extended or cancelled by
some event. Creating a normal timer and simply cancelling may not be sufficient
as the timer may have already fired when the event handler attemps to cancel it.
Even if the timer and event handler obtains L before doing work, once the event
handler releases L, the timer will eventually obtain L and do some unwanted
work.

To prevent the timer from doing unwanted work, it checks if it should early
return instead of doing the normal work after obtaining L. When stopping the
timer callers must have L locked so the timer can be safely informed that it
should early return.

Test: Tests that CancellableTimer fires and resets properly. Test to make sure
the timer fn is not called after being stopped within the lock L.
PiperOrigin-RevId: 288806984
---
 pkg/tcpip/BUILD             |   8 +
 pkg/tcpip/stack/ndp.go      | 349 ++++++++------------------------------------
 pkg/tcpip/stack/ndp_test.go |  12 +-
 pkg/tcpip/timer.go          | 161 ++++++++++++++++++++
 pkg/tcpip/timer_test.go     | 236 ++++++++++++++++++++++++++++++
 5 files changed, 473 insertions(+), 293 deletions(-)
 create mode 100644 pkg/tcpip/timer.go
 create mode 100644 pkg/tcpip/timer_test.go

diff --git a/pkg/tcpip/BUILD b/pkg/tcpip/BUILD
index 65d4d0cd8..e07ebd153 100644
--- a/pkg/tcpip/BUILD
+++ b/pkg/tcpip/BUILD
@@ -10,6 +10,7 @@ go_library(
         "packet_buffer_state.go",
         "tcpip.go",
         "time_unsafe.go",
+        "timer.go",
     ],
     importpath = "gvisor.dev/gvisor/pkg/tcpip",
     visibility = ["//visibility:public"],
@@ -26,3 +27,10 @@ go_test(
     srcs = ["tcpip_test.go"],
     embed = [":tcpip"],
 )
+
+go_test(
+    name = "timer_test",
+    size = "small",
+    srcs = ["timer_test.go"],
+    deps = [":tcpip"],
+)
diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go
index 4722ec9ce..35825ebf7 100644
--- a/pkg/tcpip/stack/ndp.go
+++ b/pkg/tcpip/stack/ndp.go
@@ -299,46 +299,14 @@ type dadState struct {
 // defaultRouterState holds data associated with a default router discovered by
 // a Router Advertisement (RA).
 type defaultRouterState struct {
-	invalidationTimer *time.Timer
-
-	// Used to inform the timer not to invalidate the default router (R) in
-	// a race condition (T1 is a goroutine that handles an RA from R and T2
-	// is the goroutine that handles R's invalidation timer firing):
-	//   T1: Receive a new RA from R
-	//   T1: Obtain the NIC's lock before processing the RA
-	//   T2: R's invalidation timer fires, and gets blocked on obtaining the
-	//       NIC's lock
-	//   T1: Refreshes/extends R's lifetime & releases NIC's lock
-	//   T2: Obtains NIC's lock & invalidates R immediately
-	//
-	// To resolve this, T1 will check to see if the timer already fired, and
-	// inform the timer using doNotInvalidate to not invalidate R, so that
-	// once T2 obtains the lock, it will see that it is set to true and do
-	// nothing further.
-	doNotInvalidate *bool
+	invalidationTimer tcpip.CancellableTimer
 }
 
 // onLinkPrefixState holds data associated with an on-link prefix discovered by
 // a Router Advertisement's Prefix Information option (PI) when the NDP
 // configurations was configured to do so.
 type onLinkPrefixState struct {
-	invalidationTimer *time.Timer
-
-	// Used to signal the timer not to invalidate the on-link prefix (P) in
-	// a race condition (T1 is a goroutine that handles a PI for P and T2
-	// is the goroutine that handles P's invalidation timer firing):
-	//   T1: Receive a new PI for P
-	//   T1: Obtain the NIC's lock before processing the PI
-	//   T2: P's invalidation timer fires, and gets blocked on obtaining the
-	//       NIC's lock
-	//   T1: Refreshes/extends P's lifetime & releases NIC's lock
-	//   T2: Obtains NIC's lock & invalidates P immediately
-	//
-	// To resolve this, T1 will check to see if the timer already fired, and
-	// inform the timer using doNotInvalidate to not invalidate P, so that
-	// once T2 obtains the lock, it will see that it is set to true and do
-	// nothing further.
-	doNotInvalidate *bool
+	invalidationTimer tcpip.CancellableTimer
 }
 
 // autoGenAddressState holds data associated with an address generated via
@@ -348,33 +316,10 @@ type autoGenAddressState struct {
 	// is holding state for.
 	ref *referencedNetworkEndpoint
 
-	deprecationTimer *time.Timer
-
-	// Used to signal the timer not to deprecate the SLAAC address in a race
-	// condition. Used for the same reason as doNotInvalidate, but for deprecating
-	// an address.
-	doNotDeprecate *bool
+	deprecationTimer  tcpip.CancellableTimer
+	invalidationTimer tcpip.CancellableTimer
 
-	invalidationTimer *time.Timer
-
-	// Used to signal the timer not to invalidate the SLAAC address (A) in
-	// a race condition (T1 is a goroutine that handles a PI for A and T2
-	// is the goroutine that handles A's invalidation timer firing):
-	//   T1: Receive a new PI for A
-	//   T1: Obtain the NIC's lock before processing the PI
-	//   T2: A's invalidation timer fires, and gets blocked on obtaining the
-	//       NIC's lock
-	//   T1: Refreshes/extends A's lifetime & releases NIC's lock
-	//   T2: Obtains NIC's lock & invalidates A immediately
-	//
-	// To resolve this, T1 will check to see if the timer already fired, and
-	// inform the timer using doNotInvalidate to not invalidate A, so that
-	// once T2 obtains the lock, it will see that it is set to true and do
-	// nothing further.
-	doNotInvalidate *bool
-
-	// Nonzero only when the address is not valid forever (invalidationTimer
-	// is not nil).
+	// Nonzero only when the address is not valid forever.
 	validUntil time.Time
 }
 
@@ -576,7 +521,7 @@ func (ndp *ndpState) stopDuplicateAddressDetection(addr tcpip.Address) {
 // handleRA handles a Router Advertisement message that arrived on the NIC
 // this ndp is for. Does nothing if the NIC is configured to not handle RAs.
 //
-// The NIC that ndp belongs to and its associated stack MUST be locked.
+// The NIC that ndp belongs to MUST be locked.
 func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) {
 	// Is the NIC configured to handle RAs at all?
 	//
@@ -605,27 +550,9 @@ func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) {
 		case ok && rl != 0:
 			// This is an already discovered default router. Update
 			// the invalidation timer.
-			timer := rtr.invalidationTimer
-
-			// We should ALWAYS have an invalidation timer for a
-			// discovered router.
-			if timer == nil {
-				panic("ndphandlera: RA invalidation timer should not be nil")
-			}
-
-			if !timer.Stop() {
-				// If we reach this point, then we know the
-				// timer fired after we already took the NIC
-				// lock. Inform the timer not to invalidate the
-				// router when it obtains the lock as we just
-				// got a new RA that refreshes its lifetime to a
-				// non-zero value. See
-				// defaultRouterState.doNotInvalidate for more
-				// details.
-				*rtr.doNotInvalidate = true
-			}
-
-			timer.Reset(rl)
+			rtr.invalidationTimer.StopLocked()
+			rtr.invalidationTimer.Reset(rl)
+			ndp.defaultRouters[ip] = rtr
 
 		case ok && rl == 0:
 			// We know about the router but it is no longer to be
@@ -692,10 +619,7 @@ func (ndp *ndpState) invalidateDefaultRouter(ip tcpip.Address) {
 		return
 	}
 
-	rtr.invalidationTimer.Stop()
-	rtr.invalidationTimer = nil
-	*rtr.doNotInvalidate = true
-	rtr.doNotInvalidate = nil
+	rtr.invalidationTimer.StopLocked()
 
 	delete(ndp.defaultRouters, ip)
 
@@ -724,27 +648,15 @@ func (ndp *ndpState) rememberDefaultRouter(ip tcpip.Address, rl time.Duration) {
 		return
 	}
 
-	// Used to signal the timer not to invalidate the default router (R) in
-	// a race condition. See defaultRouterState.doNotInvalidate for more
-	// details.
-	var doNotInvalidate bool
-
-	ndp.defaultRouters[ip] = defaultRouterState{
-		invalidationTimer: time.AfterFunc(rl, func() {
-			ndp.nic.stack.mu.Lock()
-			defer ndp.nic.stack.mu.Unlock()
-			ndp.nic.mu.Lock()
-			defer ndp.nic.mu.Unlock()
-
-			if doNotInvalidate {
-				doNotInvalidate = false
-				return
-			}
-
+	state := defaultRouterState{
+		invalidationTimer: tcpip.MakeCancellableTimer(&ndp.nic.mu, func() {
 			ndp.invalidateDefaultRouter(ip)
 		}),
-		doNotInvalidate: &doNotInvalidate,
 	}
+
+	state.invalidationTimer.Reset(rl)
+
+	ndp.defaultRouters[ip] = state
 }
 
 // rememberOnLinkPrefix remembers a newly discovered on-link prefix with IPv6
@@ -766,21 +678,17 @@ func (ndp *ndpState) rememberOnLinkPrefix(prefix tcpip.Subnet, l time.Duration)
 		return
 	}
 
-	// Used to signal the timer not to invalidate the on-link prefix (P) in
-	// a race condition. See onLinkPrefixState.doNotInvalidate for more
-	// details.
-	var doNotInvalidate bool
-	var timer *time.Timer
+	state := onLinkPrefixState{
+		invalidationTimer: tcpip.MakeCancellableTimer(&ndp.nic.mu, func() {
+			ndp.invalidateOnLinkPrefix(prefix)
+		}),
+	}
 
-	// Only create a timer if the lifetime is not infinite.
 	if l < header.NDPInfiniteLifetime {
-		timer = ndp.prefixInvalidationCallback(prefix, l, &doNotInvalidate)
+		state.invalidationTimer.Reset(l)
 	}
 
-	ndp.onLinkPrefixes[prefix] = onLinkPrefixState{
-		invalidationTimer: timer,
-		doNotInvalidate:   &doNotInvalidate,
-	}
+	ndp.onLinkPrefixes[prefix] = state
 }
 
 // invalidateOnLinkPrefix invalidates a discovered on-link prefix.
@@ -795,13 +703,7 @@ func (ndp *ndpState) invalidateOnLinkPrefix(prefix tcpip.Subnet) {
 		return
 	}
 
-	if s.invalidationTimer != nil {
-		s.invalidationTimer.Stop()
-		s.invalidationTimer = nil
-		*s.doNotInvalidate = true
-	}
-
-	s.doNotInvalidate = nil
+	s.invalidationTimer.StopLocked()
 
 	delete(ndp.onLinkPrefixes, prefix)
 
@@ -811,28 +713,6 @@ func (ndp *ndpState) invalidateOnLinkPrefix(prefix tcpip.Subnet) {
 	}
 }
 
-// prefixInvalidationCallback returns a new on-link prefix invalidation timer
-// for prefix that fires after vl.
-//
-// doNotInvalidate is used to signal the timer when it fires at the same time
-// that a prefix's valid lifetime gets refreshed. See
-// onLinkPrefixState.doNotInvalidate for more details.
-func (ndp *ndpState) prefixInvalidationCallback(prefix tcpip.Subnet, vl time.Duration, doNotInvalidate *bool) *time.Timer {
-	return time.AfterFunc(vl, func() {
-		ndp.nic.stack.mu.Lock()
-		defer ndp.nic.stack.mu.Unlock()
-		ndp.nic.mu.Lock()
-		defer ndp.nic.mu.Unlock()
-
-		if *doNotInvalidate {
-			*doNotInvalidate = false
-			return
-		}
-
-		ndp.invalidateOnLinkPrefix(prefix)
-	})
-}
-
 // handleOnLinkPrefixInformation handles a Prefix Information option with
 // its on-link flag set, as per RFC 4861 section 6.3.4.
 //
@@ -872,42 +752,17 @@ func (ndp *ndpState) handleOnLinkPrefixInformation(pi header.NDPPrefixInformatio
 
 	// This is an already discovered on-link prefix with a
 	// new non-zero valid lifetime.
+	//
 	// Update the invalidation timer.
-	timer := prefixState.invalidationTimer
-
-	if timer == nil && vl >= header.NDPInfiniteLifetime {
-		// Had infinite valid lifetime before and
-		// continues to have an invalid lifetime. Do
-		// nothing further.
-		return
-	}
 
-	if timer != nil && !timer.Stop() {
-		// If we reach this point, then we know the timer alread fired
-		// after we took the NIC lock. Inform the timer to not
-		// invalidate the prefix once it obtains the lock as we just
-		// got a new PI that refreshes its lifetime to a non-zero value.
-		// See onLinkPrefixState.doNotInvalidate for more details.
-		*prefixState.doNotInvalidate = true
-	}
+	prefixState.invalidationTimer.StopLocked()
 
-	if vl >= header.NDPInfiniteLifetime {
-		// Prefix is now valid forever so we don't need
-		// an invalidation timer.
-		prefixState.invalidationTimer = nil
-		ndp.onLinkPrefixes[prefix] = prefixState
-		return
-	}
-
-	if timer != nil {
-		// We already have a timer so just reset it to
-		// expire after the new valid lifetime.
-		timer.Reset(vl)
-		return
+	if vl < header.NDPInfiniteLifetime {
+		// Prefix is valid for a finite lifetime, reset the timer to expire after
+		// the new valid lifetime.
+		prefixState.invalidationTimer.Reset(vl)
 	}
 
-	// We do not have a timer so just create a new one.
-	prefixState.invalidationTimer = ndp.prefixInvalidationCallback(prefix, vl, prefixState.doNotInvalidate)
 	ndp.onLinkPrefixes[prefix] = prefixState
 }
 
@@ -917,7 +772,7 @@ func (ndp *ndpState) handleOnLinkPrefixInformation(pi header.NDPPrefixInformatio
 // handleAutonomousPrefixInformation assumes that the prefix this pi is for is
 // not the link-local prefix and the autonomous flag is set.
 //
-// The NIC that ndp belongs to and its associated stack MUST be locked.
+// The NIC that ndp belongs to MUST be locked.
 func (ndp *ndpState) handleAutonomousPrefixInformation(pi header.NDPPrefixInformation) {
 	vl := pi.ValidLifetime()
 	pl := pi.PreferredLifetime()
@@ -1026,28 +881,34 @@ func (ndp *ndpState) newAutoGenAddress(prefix tcpip.Subnet, pl, vl time.Duration
 		log.Fatalf("ndp: error when adding address %s: %s", protocolAddr, err)
 	}
 
-	// Setup the timers to deprecate and invalidate this newly generated address.
+	state := autoGenAddressState{
+		ref: ref,
+		deprecationTimer: tcpip.MakeCancellableTimer(&ndp.nic.mu, func() {
+			addrState, ok := ndp.autoGenAddresses[addr]
+			if !ok {
+				log.Fatalf("ndp: must have an autoGenAddressess entry for the SLAAC generated IPv6 address %s", addr)
+			}
+			addrState.ref.deprecated = true
+			ndp.notifyAutoGenAddressDeprecated(addr)
+		}),
+		invalidationTimer: tcpip.MakeCancellableTimer(&ndp.nic.mu, func() {
+			ndp.invalidateAutoGenAddress(addr)
+		}),
+	}
+
+	// Setup the initial timers to deprecate and invalidate this newly generated
+	// address.
 
-	var doNotDeprecate bool
-	var pTimer *time.Timer
 	if !deprecated && pl < header.NDPInfiniteLifetime {
-		pTimer = ndp.autoGenAddrDeprecationTimer(addr, pl, &doNotDeprecate)
+		state.deprecationTimer.Reset(pl)
 	}
 
-	var doNotInvalidate bool
-	var vTimer *time.Timer
 	if vl < header.NDPInfiniteLifetime {
-		vTimer = ndp.autoGenAddrInvalidationTimer(addr, vl, &doNotInvalidate)
+		state.invalidationTimer.Reset(vl)
+		state.validUntil = time.Now().Add(vl)
 	}
 
-	ndp.autoGenAddresses[addr] = autoGenAddressState{
-		ref:               ref,
-		deprecationTimer:  pTimer,
-		doNotDeprecate:    &doNotDeprecate,
-		invalidationTimer: vTimer,
-		doNotInvalidate:   &doNotInvalidate,
-		validUntil:        time.Now().Add(vl),
-	}
+	ndp.autoGenAddresses[addr] = state
 }
 
 // refreshAutoGenAddressLifetimes refreshes the lifetime of a SLAAC generated
@@ -1075,20 +936,10 @@ func (ndp *ndpState) refreshAutoGenAddressLifetimes(addr tcpip.Address, pl, vl t
 
 	// If addr was preferred for some finite lifetime before, stop the deprecation
 	// timer so it can be reset.
-	if t := addrState.deprecationTimer; t != nil && !t.Stop() {
-		*addrState.doNotDeprecate = true
-	}
+	addrState.deprecationTimer.StopLocked()
 
-	// Reset the deprecation timer.
-	if pl >= header.NDPInfiniteLifetime || deprecated {
-		// If addr is preferred forever or it has been deprecated already, there is
-		// no need for a deprecation timer.
-		addrState.deprecationTimer = nil
-	} else if addrState.deprecationTimer == nil {
-		// addr is now preferred for a finite lifetime.
-		addrState.deprecationTimer = ndp.autoGenAddrDeprecationTimer(addr, pl, addrState.doNotDeprecate)
-	} else {
-		// addr continues to be preferred for a finite lifetime.
+	// Reset the deprecation timer if addr has a finite preferred lifetime.
+	if !deprecated && pl < header.NDPInfiniteLifetime {
 		addrState.deprecationTimer.Reset(pl)
 	}
 
@@ -1107,15 +958,8 @@ func (ndp *ndpState) refreshAutoGenAddressLifetimes(addr tcpip.Address, pl, vl t
 	// Handle the infinite valid lifetime separately as we do not keep a timer in
 	// this case.
 	if vl >= header.NDPInfiniteLifetime {
-		if addrState.invalidationTimer != nil {
-			// Valid lifetime was finite before, but now it is valid forever.
-			if !addrState.invalidationTimer.Stop() {
-				*addrState.doNotInvalidate = true
-			}
-			addrState.invalidationTimer = nil
-			addrState.validUntil = time.Time{}
-		}
-
+		addrState.invalidationTimer.StopLocked()
+		addrState.validUntil = time.Time{}
 		return
 	}
 
@@ -1124,7 +968,7 @@ func (ndp *ndpState) refreshAutoGenAddressLifetimes(addr tcpip.Address, pl, vl t
 
 	// If the address was originally set to be valid forever, assume the remaining
 	// time to be the maximum possible value.
-	if addrState.invalidationTimer == nil {
+	if addrState.validUntil == (time.Time{}) {
 		rl = header.NDPInfiniteLifetime
 	} else {
 		rl = time.Until(addrState.validUntil)
@@ -1138,15 +982,8 @@ func (ndp *ndpState) refreshAutoGenAddressLifetimes(addr tcpip.Address, pl, vl t
 		effectiveVl = MinPrefixInformationValidLifetimeForUpdate
 	}
 
-	if addrState.invalidationTimer == nil {
-		addrState.invalidationTimer = ndp.autoGenAddrInvalidationTimer(addr, effectiveVl, addrState.doNotInvalidate)
-	} else {
-		if !addrState.invalidationTimer.Stop() {
-			*addrState.doNotInvalidate = true
-		}
-		addrState.invalidationTimer.Reset(effectiveVl)
-	}
-
+	addrState.invalidationTimer.StopLocked()
+	addrState.invalidationTimer.Reset(effectiveVl)
 	addrState.validUntil = time.Now().Add(effectiveVl)
 }
 
@@ -1181,27 +1018,12 @@ func (ndp *ndpState) invalidateAutoGenAddress(addr tcpip.Address) {
 // The NIC that ndp belongs to MUST be locked.
 func (ndp *ndpState) cleanupAutoGenAddrResourcesAndNotify(addr tcpip.Address) bool {
 	state, ok := ndp.autoGenAddresses[addr]
-
 	if !ok {
 		return false
 	}
 
-	if state.deprecationTimer != nil {
-		state.deprecationTimer.Stop()
-		state.deprecationTimer = nil
-		*state.doNotDeprecate = true
-	}
-
-	state.doNotDeprecate = nil
-
-	if state.invalidationTimer != nil {
-		state.invalidationTimer.Stop()
-		state.invalidationTimer = nil
-		*state.doNotInvalidate = true
-	}
-
-	state.doNotInvalidate = nil
-
+	state.deprecationTimer.StopLocked()
+	state.invalidationTimer.StopLocked()
 	delete(ndp.autoGenAddresses, addr)
 
 	if ndpDisp := ndp.nic.stack.ndpDisp; ndpDisp != nil {
@@ -1214,53 +1036,6 @@ func (ndp *ndpState) cleanupAutoGenAddrResourcesAndNotify(addr tcpip.Address) bo
 	return true
 }
 
-// autoGenAddrDeprecationTimer returns a new deprecation timer for an
-// auto-generated address that fires after pl.
-//
-// doNotDeprecate is used to inform the timer when it fires at the same time
-// that an auto-generated address's preferred lifetime gets refreshed. See
-// autoGenAddrState.doNotDeprecate for more details.
-func (ndp *ndpState) autoGenAddrDeprecationTimer(addr tcpip.Address, pl time.Duration, doNotDeprecate *bool) *time.Timer {
-	return time.AfterFunc(pl, func() {
-		ndp.nic.mu.Lock()
-		defer ndp.nic.mu.Unlock()
-
-		if *doNotDeprecate {
-			*doNotDeprecate = false
-			return
-		}
-
-		addrState, ok := ndp.autoGenAddresses[addr]
-		if !ok {
-			log.Fatalf("ndp: must have an autoGenAddressess entry for the SLAAC generated IPv6 address %s", addr)
-		}
-		addrState.ref.deprecated = true
-		ndp.notifyAutoGenAddressDeprecated(addr)
-		addrState.deprecationTimer = nil
-		ndp.autoGenAddresses[addr] = addrState
-	})
-}
-
-// autoGenAddrInvalidationTimer returns a new invalidation timer for an
-// auto-generated address that fires after vl.
-//
-// doNotInvalidate is used to inform the timer when it fires at the same time
-// that an auto-generated address's valid lifetime gets refreshed. See
-// autoGenAddrState.doNotInvalidate for more details.
-func (ndp *ndpState) autoGenAddrInvalidationTimer(addr tcpip.Address, vl time.Duration, doNotInvalidate *bool) *time.Timer {
-	return time.AfterFunc(vl, func() {
-		ndp.nic.mu.Lock()
-		defer ndp.nic.mu.Unlock()
-
-		if *doNotInvalidate {
-			*doNotInvalidate = false
-			return
-		}
-
-		ndp.invalidateAutoGenAddress(addr)
-	})
-}
-
 // cleanupHostOnlyState cleans up any state that is only useful for hosts.
 //
 // cleanupHostOnlyState MUST be called when ndp's NIC is transitioning from a
diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go
index e51462a55..d334af289 100644
--- a/pkg/tcpip/stack/ndp_test.go
+++ b/pkg/tcpip/stack/ndp_test.go
@@ -1029,13 +1029,13 @@ func TestRouterDiscovery(t *testing.T) {
 	expectRouterEvent(llAddr2, true)
 
 	// Rx an RA from another router (lladdr3) with non-zero lifetime.
-	l3Lifetime := time.Duration(6)
-	e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr3, uint16(l3Lifetime)))
+	const l3LifetimeSeconds = 6
+	e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr3, l3LifetimeSeconds))
 	expectRouterEvent(llAddr3, true)
 
 	// Rx an RA from lladdr2 with lesser lifetime.
-	l2Lifetime := time.Duration(2)
-	e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr2, uint16(l2Lifetime)))
+	const l2LifetimeSeconds = 2
+	e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr2, l2LifetimeSeconds))
 	select {
 	case <-ndpDisp.routerC:
 		t.Fatal("Should not receive a router event when updating lifetimes for known routers")
@@ -1049,7 +1049,7 @@ func TestRouterDiscovery(t *testing.T) {
 	// Wait for the normal lifetime plus an extra bit for the
 	// router to get invalidated. If we don't get an invalidation
 	// event after this time, then something is wrong.
-	expectAsyncRouterInvalidationEvent(llAddr2, l2Lifetime*time.Second+defaultTimeout)
+	expectAsyncRouterInvalidationEvent(llAddr2, l2LifetimeSeconds*time.Second+defaultTimeout)
 
 	// Rx an RA from lladdr2 with huge lifetime.
 	e.InjectInbound(header.IPv6ProtocolNumber, raBuf(llAddr2, 1000))
@@ -1066,7 +1066,7 @@ func TestRouterDiscovery(t *testing.T) {
 	// Wait for the normal lifetime plus an extra bit for the
 	// router to get invalidated. If we don't get an invalidation
 	// event after this time, then something is wrong.
-	expectAsyncRouterInvalidationEvent(llAddr3, l3Lifetime*time.Second+defaultTimeout)
+	expectAsyncRouterInvalidationEvent(llAddr3, l3LifetimeSeconds*time.Second+defaultTimeout)
 }
 
 // TestRouterDiscoveryMaxRouters tests that only
diff --git a/pkg/tcpip/timer.go b/pkg/tcpip/timer.go
new file mode 100644
index 000000000..f5f01f32f
--- /dev/null
+++ b/pkg/tcpip/timer.go
@@ -0,0 +1,161 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package tcpip
+
+import (
+	"sync"
+	"time"
+)
+
+// cancellableTimerInstance is a specific instance of CancellableTimer.
+//
+// Different instances are created each time CancellableTimer is Reset so each
+// timer has its own earlyReturn signal. This is to address a bug when a
+// CancellableTimer is stopped and reset in quick succession resulting in a
+// timer instance's earlyReturn signal being affected or seen by another timer
+// instance.
+//
+// Consider the following sceneario where timer instances share a common
+// earlyReturn signal (T1 creates, stops and resets a Cancellable timer under a
+// lock L; T2, T3, T4 and T5 are goroutines that handle the first (A), second
+// (B), third (C), and fourth (D) instance of the timer firing, respectively):
+//   T1: Obtain L
+//   T1: Create a new CancellableTimer w/ lock L (create instance A)
+//   T2: instance A fires, blocked trying to obtain L.
+//   T1: Attempt to stop instance A (set earlyReturn = true)
+//   T1: Reset timer (create instance B)
+//   T3: instance B fires, blocked trying to obtain L.
+//   T1: Attempt to stop instance B (set earlyReturn = true)
+//   T1: Reset timer (create instance C)
+//   T4: instance C fires, blocked trying to obtain L.
+//   T1: Attempt to stop instance C (set earlyReturn = true)
+//   T1: Reset timer (create instance D)
+//   T5: instance D fires, blocked trying to obtain L.
+//   T1: Release L
+//
+// Now that T1 has released L, any of the 4 timer instances can take L and check
+// earlyReturn. If the timers simply check earlyReturn and then do nothing
+// further, then instance D will never early return even though it was not
+// requested to stop. If the timers reset earlyReturn before early returning,
+// then all but one of the timers will do work when only one was expected to.
+// If CancellableTimer resets earlyReturn when resetting, then all the timers
+// will fire (again, when only one was expected to).
+//
+// To address the above concerns the simplest solution was to give each timer
+// its own earlyReturn signal.
+type cancellableTimerInstance struct {
+	timer *time.Timer
+
+	// Used to inform the timer to early return when it gets stopped while the
+	// lock the timer tries to obtain when fired is held (T1 is a goroutine that
+	// tries to cancel the timer and T2 is the goroutine that handles the timer
+	// firing):
+	//   T1: Obtain the lock, then call StopLocked()
+	//   T2: timer fires, and gets blocked on obtaining the lock
+	//   T1: Releases lock
+	//   T2: Obtains lock does unintended work
+	//
+	// To resolve this, T1 will check to see if the timer already fired, and
+	// inform the timer using earlyReturn to return early so that once T2 obtains
+	// the lock, it will see that it is set to true and do nothing further.
+	earlyReturn *bool
+}
+
+// stop stops the timer instance t from firing if it hasn't fired already. If it
+// has fired and is blocked at obtaining the lock, earlyReturn will be set to
+// true so that it will early return when it obtains the lock.
+func (t *cancellableTimerInstance) stop() {
+	if t.timer != nil {
+		t.timer.Stop()
+		*t.earlyReturn = true
+	}
+}
+
+// CancellableTimer is a timer that does some work and can be safely cancelled
+// when it fires at the same time some "related work" is being done.
+//
+// The term "related work" is defined as some work that needs to be done while
+// holding some lock that the timer must also hold while doing some work.
+type CancellableTimer struct {
+	// The active instance of a cancellable timer.
+	instance cancellableTimerInstance
+
+	// locker is the lock taken by the timer immediately after it fires and must
+	// be held when attempting to stop the timer.
+	//
+	// Must never change after being assigned.
+	locker sync.Locker
+
+	// fn is the function that will be called when a timer fires and has not been
+	// signaled to early return.
+	//
+	// fn MUST NOT attempt to lock locker.
+	//
+	// Must never change after being assigned.
+	fn func()
+}
+
+// StopLocked prevents the Timer from firing if it has not fired already.
+//
+// If the timer is blocked on obtaining the t.locker lock when StopLocked is
+// called, it will early return instead of calling t.fn.
+//
+// Note, t will be modified.
+//
+// t.locker MUST be locked.
+func (t *CancellableTimer) StopLocked() {
+	t.instance.stop()
+
+	// Nothing to do with the stopped instance anymore.
+	t.instance = cancellableTimerInstance{}
+}
+
+// Reset changes the timer to expire after duration d.
+//
+// Note, t will be modified.
+//
+// Reset should only be called on stopped or expired timers. To be safe, callers
+// should always call StopLocked before calling Reset.
+func (t *CancellableTimer) Reset(d time.Duration) {
+	// Create a new instance.
+	earlyReturn := false
+	t.instance = cancellableTimerInstance{
+		timer: time.AfterFunc(d, func() {
+			t.locker.Lock()
+			defer t.locker.Unlock()
+
+			if earlyReturn {
+				// If we reach this point, it means that the timer fired while another
+				// goroutine called StopLocked while it had the lock. Simply return
+				// here and do nothing further.
+				earlyReturn = false
+				return
+			}
+
+			t.fn()
+		}),
+		earlyReturn: &earlyReturn,
+	}
+}
+
+// MakeCancellableTimer returns an unscheduled CancellableTimer with the given
+// locker and fn.
+//
+// fn MUST NOT attempt to lock locker.
+//
+// Callers must call Reset to schedule the timer to fire.
+func MakeCancellableTimer(locker sync.Locker, fn func()) CancellableTimer {
+	return CancellableTimer{locker: locker, fn: fn}
+}
diff --git a/pkg/tcpip/timer_test.go b/pkg/tcpip/timer_test.go
new file mode 100644
index 000000000..1f735d735
--- /dev/null
+++ b/pkg/tcpip/timer_test.go
@@ -0,0 +1,236 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package timer_test
+
+import (
+	"sync"
+	"testing"
+	"time"
+
+	"gvisor.dev/gvisor/pkg/tcpip"
+)
+
+const (
+	shortDuration  = 1 * time.Nanosecond
+	middleDuration = 100 * time.Millisecond
+	longDuration   = 1 * time.Second
+)
+
+func TestCancellableTimerFire(t *testing.T) {
+	t.Parallel()
+
+	ch := make(chan struct{})
+	var lock sync.Mutex
+
+	timer := tcpip.MakeCancellableTimer(&lock, func() {
+		ch <- struct{}{}
+	})
+	timer.Reset(shortDuration)
+
+	// Wait for timer to fire.
+	select {
+	case <-ch:
+	case <-time.After(middleDuration):
+		t.Fatal("timed out waiting for timer to fire")
+	}
+
+	// The timer should have fired only once.
+	select {
+	case <-ch:
+		t.Fatal("no other timers should have fired")
+	case <-time.After(middleDuration):
+	}
+}
+
+func TestCancellableTimerResetFromLongDuration(t *testing.T) {
+	t.Parallel()
+
+	ch := make(chan struct{})
+	var lock sync.Mutex
+
+	timer := tcpip.MakeCancellableTimer(&lock, func() { ch <- struct{}{} })
+	timer.Reset(middleDuration)
+
+	lock.Lock()
+	timer.StopLocked()
+	lock.Unlock()
+
+	timer.Reset(shortDuration)
+
+	// Wait for timer to fire.
+	select {
+	case <-ch:
+	case <-time.After(middleDuration):
+		t.Fatal("timed out waiting for timer to fire")
+	}
+
+	// The timer should have fired only once.
+	select {
+	case <-ch:
+		t.Fatal("no other timers should have fired")
+	case <-time.After(middleDuration):
+	}
+}
+
+func TestCancellableTimerResetFromShortDuration(t *testing.T) {
+	t.Parallel()
+
+	ch := make(chan struct{})
+	var lock sync.Mutex
+
+	lock.Lock()
+	timer := tcpip.MakeCancellableTimer(&lock, func() { ch <- struct{}{} })
+	timer.Reset(shortDuration)
+	timer.StopLocked()
+	lock.Unlock()
+
+	// Wait for timer to fire if it wasn't correctly stopped.
+	select {
+	case <-ch:
+		t.Fatal("timer fired after being stopped")
+	case <-time.After(middleDuration):
+	}
+
+	timer.Reset(shortDuration)
+
+	// Wait for timer to fire.
+	select {
+	case <-ch:
+	case <-time.After(middleDuration):
+		t.Fatal("timed out waiting for timer to fire")
+	}
+
+	// The timer should have fired only once.
+	select {
+	case <-ch:
+		t.Fatal("no other timers should have fired")
+	case <-time.After(middleDuration):
+	}
+}
+
+func TestCancellableTimerImmediatelyStop(t *testing.T) {
+	t.Parallel()
+
+	ch := make(chan struct{})
+	var lock sync.Mutex
+
+	for i := 0; i < 1000; i++ {
+		lock.Lock()
+		timer := tcpip.MakeCancellableTimer(&lock, func() { ch <- struct{}{} })
+		timer.Reset(shortDuration)
+		timer.StopLocked()
+		lock.Unlock()
+	}
+
+	// Wait for timer to fire if it wasn't correctly stopped.
+	select {
+	case <-ch:
+		t.Fatal("timer fired after being stopped")
+	case <-time.After(middleDuration):
+	}
+}
+
+func TestCancellableTimerStoppedResetWithoutLock(t *testing.T) {
+	t.Parallel()
+
+	ch := make(chan struct{})
+	var lock sync.Mutex
+
+	lock.Lock()
+	timer := tcpip.MakeCancellableTimer(&lock, func() { ch <- struct{}{} })
+	timer.Reset(shortDuration)
+	timer.StopLocked()
+	lock.Unlock()
+
+	for i := 0; i < 10; i++ {
+		timer.Reset(middleDuration)
+
+		lock.Lock()
+		// Sleep until the timer fires and gets blocked trying to take the lock.
+		time.Sleep(middleDuration * 2)
+		timer.StopLocked()
+		lock.Unlock()
+	}
+
+	// Wait for double the duration so timers that weren't correctly stopped can
+	// fire.
+	select {
+	case <-ch:
+		t.Fatal("timer fired after being stopped")
+	case <-time.After(middleDuration * 2):
+	}
+}
+
+func TestManyCancellableTimerResetAfterBlockedOnLock(t *testing.T) {
+	t.Parallel()
+
+	ch := make(chan struct{})
+	var lock sync.Mutex
+
+	lock.Lock()
+	timer := tcpip.MakeCancellableTimer(&lock, func() { ch <- struct{}{} })
+	timer.Reset(shortDuration)
+	for i := 0; i < 10; i++ {
+		// Sleep until the timer fires and gets blocked trying to take the lock.
+		time.Sleep(middleDuration)
+		timer.StopLocked()
+		timer.Reset(shortDuration)
+	}
+	lock.Unlock()
+
+	// Wait for double the duration for the last timer to fire.
+	select {
+	case <-ch:
+	case <-time.After(middleDuration):
+		t.Fatal("timed out waiting for timer to fire")
+	}
+
+	// The timer should have fired only once.
+	select {
+	case <-ch:
+		t.Fatal("no other timers should have fired")
+	case <-time.After(middleDuration):
+	}
+}
+
+func TestManyCancellableTimerResetUnderLock(t *testing.T) {
+	t.Parallel()
+
+	ch := make(chan struct{})
+	var lock sync.Mutex
+
+	lock.Lock()
+	timer := tcpip.MakeCancellableTimer(&lock, func() { ch <- struct{}{} })
+	timer.Reset(shortDuration)
+	for i := 0; i < 10; i++ {
+		timer.StopLocked()
+		timer.Reset(shortDuration)
+	}
+	lock.Unlock()
+
+	// Wait for double the duration for the last timer to fire.
+	select {
+	case <-ch:
+	case <-time.After(middleDuration):
+		t.Fatal("timed out waiting for timer to fire")
+	}
+
+	// The timer should have fired only once.
+	select {
+	case <-ch:
+		t.Fatal("no other timers should have fired")
+	case <-time.After(middleDuration):
+	}
+}
-- 
cgit v1.2.3


From 290908fa8ae2363c3d2a7af7cef8d5dda622cde7 Mon Sep 17 00:00:00 2001
From: Fabricio Voznika <fvoznika@google.com>
Date: Thu, 9 Jan 2020 10:16:02 -0800
Subject: Configure issue reviver to run with Kokoro

PiperOrigin-RevId: 288921032
---
 kokoro/issue_reviver.cfg | 15 +++++++++++++++
 scripts/issue_reviver.sh | 27 +++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)
 create mode 100644 kokoro/issue_reviver.cfg
 create mode 100755 scripts/issue_reviver.sh

diff --git a/kokoro/issue_reviver.cfg b/kokoro/issue_reviver.cfg
new file mode 100644
index 000000000..2370d9250
--- /dev/null
+++ b/kokoro/issue_reviver.cfg
@@ -0,0 +1,15 @@
+build_file: "repo/scripts/issue_reviver.sh"
+
+before_action {
+  fetch_keystore {
+    keystore_resource {
+      keystore_config_id: 73898
+      keyname: "kokoro-github-access-token"
+    }
+  }
+}
+
+env_vars {
+  key: "KOKORO_GITHUB_ACCESS_TOKEN"
+  value: "73898_kokoro-github-access-token"
+}
diff --git a/scripts/issue_reviver.sh b/scripts/issue_reviver.sh
new file mode 100755
index 000000000..bac9b9192
--- /dev/null
+++ b/scripts/issue_reviver.sh
@@ -0,0 +1,27 @@
+#!/bin/bash
+
+# Copyright 2019 The gVisor Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+DIR=$(dirname $0)
+source "${DIR}"/common.sh
+
+# Provide a credential file if available.
+export OAUTH_TOKEN_FILE=""
+if [[ -v KOKORO_GITHUB_ACCESS_TOKEN ]]; then
+  OAUTH_TOKEN_FILE="${KOKORO_KEYSTORE_DIR}/${KOKORO_GITHUB_ACCESS_TOKEN}"
+fi
+
+REPO_ROOT=$(cd "$(dirname "${DIR}")"; pwd)
+run //tools/issue_reviver:issue_reviver --path "${REPO_ROOT}" --oauth-token-file="${OAUTH_TOKEN_FILE}"
-- 
cgit v1.2.3


From e752ddbb72d89b19863a6b50d99814149a08d5fe Mon Sep 17 00:00:00 2001
From: Bert Muthalaly <stijlist@google.com>
Date: Thu, 9 Jan 2020 10:34:30 -0800
Subject: Allow clients to store an opaque NICContext with NICs

...retrievable later via stack.NICInfo().

Clients of this library can use it to add metadata that should be tracked
alongside a NIC, to avoid having to keep a map[tcpip.NICID]metadata mirroring
stack.Stack's nic map.

PiperOrigin-RevId: 288924900
---
 pkg/tcpip/stack/nic.go        | 12 +++++++-----
 pkg/tcpip/stack/stack.go      | 16 +++++++++++++++-
 pkg/tcpip/stack/stack_test.go | 40 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 62 insertions(+), 6 deletions(-)

diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go
index 4144d5d0f..3810c6602 100644
--- a/pkg/tcpip/stack/nic.go
+++ b/pkg/tcpip/stack/nic.go
@@ -27,10 +27,11 @@ import (
 // NIC represents a "network interface card" to which the networking stack is
 // attached.
 type NIC struct {
-	stack  *Stack
-	id     tcpip.NICID
-	name   string
-	linkEP LinkEndpoint
+	stack   *Stack
+	id      tcpip.NICID
+	name    string
+	linkEP  LinkEndpoint
+	context NICContext
 
 	mu            sync.RWMutex
 	spoofing      bool
@@ -84,7 +85,7 @@ const (
 )
 
 // newNIC returns a new NIC using the default NDP configurations from stack.
-func newNIC(stack *Stack, id tcpip.NICID, name string, ep LinkEndpoint) *NIC {
+func newNIC(stack *Stack, id tcpip.NICID, name string, ep LinkEndpoint, ctx NICContext) *NIC {
 	// TODO(b/141011931): Validate a LinkEndpoint (ep) is valid. For
 	// example, make sure that the link address it provides is a valid
 	// unicast ethernet address.
@@ -98,6 +99,7 @@ func newNIC(stack *Stack, id tcpip.NICID, name string, ep LinkEndpoint) *NIC {
 		id:         id,
 		name:       name,
 		linkEP:     ep,
+		context:    ctx,
 		primary:    make(map[tcpip.NetworkProtocolNumber][]*referencedNetworkEndpoint),
 		endpoints:  make(map[NetworkEndpointID]*referencedNetworkEndpoint),
 		mcastJoins: make(map[NetworkEndpointID]int32),
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index fb7ac409e..e2a2edb2c 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -796,6 +796,9 @@ func (s *Stack) NewPacketEndpoint(cooked bool, netProto tcpip.NetworkProtocolNum
 	return s.rawFactory.NewPacketEndpoint(s, cooked, netProto, waiterQueue)
 }
 
+// NICContext is an opaque pointer used to store client-supplied NIC metadata.
+type NICContext interface{}
+
 // NICOptions specifies the configuration of a NIC as it is being created.
 // The zero value creates an enabled, unnamed NIC.
 type NICOptions struct {
@@ -805,6 +808,12 @@ type NICOptions struct {
 	// Disabled specifies whether to avoid calling Attach on the passed
 	// LinkEndpoint.
 	Disabled bool
+
+	// Context specifies user-defined data that will be returned in stack.NICInfo
+	// for the NIC. Clients of this library can use it to add metadata that
+	// should be tracked alongside a NIC, to avoid having to keep a
+	// map[tcpip.NICID]metadata mirroring stack.Stack's nic map.
+	Context NICContext
 }
 
 // CreateNICWithOptions creates a NIC with the provided id, LinkEndpoint, and
@@ -819,7 +828,7 @@ func (s *Stack) CreateNICWithOptions(id tcpip.NICID, ep LinkEndpoint, opts NICOp
 		return tcpip.ErrDuplicateNICID
 	}
 
-	n := newNIC(s, id, opts.Name, ep)
+	n := newNIC(s, id, opts.Name, ep, opts.Context)
 
 	s.nics[id] = n
 	if !opts.Disabled {
@@ -886,6 +895,10 @@ type NICInfo struct {
 	MTU uint32
 
 	Stats NICStats
+
+	// Context is user-supplied data optionally supplied in CreateNICWithOptions.
+	// See type NICOptions for more details.
+	Context NICContext
 }
 
 // NICInfo returns a map of NICIDs to their associated information.
@@ -908,6 +921,7 @@ func (s *Stack) NICInfo() map[tcpip.NICID]NICInfo {
 			Flags:             flags,
 			MTU:               nic.linkEP.MTU(),
 			Stats:             nic.stats,
+			Context:           nic.context,
 		}
 	}
 	return nics
diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go
index 9ac50bb23..44e5229cc 100644
--- a/pkg/tcpip/stack/stack_test.go
+++ b/pkg/tcpip/stack/stack_test.go
@@ -2001,6 +2001,46 @@ func TestNICAutoGenAddr(t *testing.T) {
 	}
 }
 
+// TestNICContextPreservation tests that you can read out via stack.NICInfo the
+// Context data you pass via NICContext.Context in stack.CreateNICWithOptions.
+func TestNICContextPreservation(t *testing.T) {
+	var ctx *int
+	tests := []struct {
+		name string
+		opts stack.NICOptions
+		want stack.NICContext
+	}{
+		{
+			"context_set",
+			stack.NICOptions{Context: ctx},
+			ctx,
+		},
+		{
+			"context_not_set",
+			stack.NICOptions{},
+			nil,
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			s := stack.New(stack.Options{})
+			id := tcpip.NICID(1)
+			ep := channel.New(0, 0, tcpip.LinkAddress("\x00\x00\x00\x00\x00\x00"))
+			if err := s.CreateNICWithOptions(id, ep, test.opts); err != nil {
+				t.Fatalf("got stack.CreateNICWithOptions(%d, %+v, %+v) = %s, want nil", id, ep, test.opts, err)
+			}
+			nicinfos := s.NICInfo()
+			nicinfo, ok := nicinfos[id]
+			if !ok {
+				t.Fatalf("got nicinfos[%d] = _, %t, want _, true; nicinfos = %+v", id, ok, nicinfos)
+			}
+			if got, want := nicinfo.Context == test.want, true; got != want {
+				t.Fatal("got nicinfo.Context == ctx = %t, want %t; nicinfo.Context = %p, ctx = %p", got, want, nicinfo.Context, test.want)
+			}
+		})
+	}
+}
+
 // TestNICAutoGenAddrWithOpaque tests the auto-generation of IPv6 link-local
 // addresses with opaque interface identifiers. Link Local addresses should
 // always be generated with opaque IIDs if configured to use them, even if the
-- 
cgit v1.2.3


From 8643933d6e58492cbe9d5c78124873ab40f65feb Mon Sep 17 00:00:00 2001
From: Eyal Soha <eyalsoha@google.com>
Date: Thu, 9 Jan 2020 13:06:24 -0800
Subject: Change BindToDeviceOption to store NICID

This makes it possible to call the sockopt from go even when the NIC has no
name.

PiperOrigin-RevId: 288955236
---
 pkg/sentry/socket/netstack/netstack.go    | 29 ++++++++--
 pkg/tcpip/stack/stack.go                  |  8 +++
 pkg/tcpip/stack/transport_demuxer_test.go | 89 +++++++++++++++----------------
 pkg/tcpip/tcpip.go                        |  2 +-
 pkg/tcpip/transport/tcp/endpoint.go       | 27 ++++------
 pkg/tcpip/transport/tcp/tcp_test.go       | 42 +++++++--------
 pkg/tcpip/transport/udp/endpoint.go       | 27 ++++------
 pkg/tcpip/transport/udp/udp_test.go       | 31 +++++------
 8 files changed, 127 insertions(+), 128 deletions(-)

diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go
index 9e0d69046..764f11a6b 100644
--- a/pkg/sentry/socket/netstack/netstack.go
+++ b/pkg/sentry/socket/netstack/netstack.go
@@ -985,13 +985,23 @@ func getSockOptSocket(t *kernel.Task, s socket.Socket, ep commonEndpoint, family
 		if err := ep.GetSockOpt(&v); err != nil {
 			return nil, syserr.TranslateNetstackError(err)
 		}
-		if len(v) == 0 {
+		if v == 0 {
 			return []byte{}, nil
 		}
 		if outLen < linux.IFNAMSIZ {
 			return nil, syserr.ErrInvalidArgument
 		}
-		return append([]byte(v), 0), nil
+		s := t.NetworkContext()
+		if s == nil {
+			return nil, syserr.ErrNoDevice
+		}
+		nic, ok := s.Interfaces()[int32(v)]
+		if !ok {
+			// The NICID no longer indicates a valid interface, probably because that
+			// interface was removed.
+			return nil, syserr.ErrUnknownDevice
+		}
+		return append([]byte(nic.Name), 0), nil
 
 	case linux.SO_BROADCAST:
 		if outLen < sizeOfInt32 {
@@ -1438,7 +1448,20 @@ func setSockOptSocket(t *kernel.Task, s socket.Socket, ep commonEndpoint, name i
 		if n == -1 {
 			n = len(optVal)
 		}
-		return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.BindToDeviceOption(optVal[:n])))
+		name := string(optVal[:n])
+		if name == "" {
+			return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.BindToDeviceOption(0)))
+		}
+		s := t.NetworkContext()
+		if s == nil {
+			return syserr.ErrNoDevice
+		}
+		for nicID, nic := range s.Interfaces() {
+			if nic.Name == name {
+				return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.BindToDeviceOption(nicID)))
+			}
+		}
+		return syserr.ErrUnknownDevice
 
 	case linux.SO_BROADCAST:
 		if len(optVal) < sizeOfInt32 {
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index e2a2edb2c..41bf9fd9b 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -901,6 +901,14 @@ type NICInfo struct {
 	Context NICContext
 }
 
+// HasNIC returns true if the NICID is defined in the stack.
+func (s *Stack) HasNIC(id tcpip.NICID) bool {
+	s.mu.RLock()
+	_, ok := s.nics[id]
+	s.mu.RUnlock()
+	return ok
+}
+
 // NICInfo returns a map of NICIDs to their associated information.
 func (s *Stack) NICInfo() map[tcpip.NICID]NICInfo {
 	s.mu.RLock()
diff --git a/pkg/tcpip/stack/transport_demuxer_test.go b/pkg/tcpip/stack/transport_demuxer_test.go
index df5ced887..5e9237de9 100644
--- a/pkg/tcpip/stack/transport_demuxer_test.go
+++ b/pkg/tcpip/stack/transport_demuxer_test.go
@@ -41,7 +41,7 @@ const (
 
 type testContext struct {
 	t       *testing.T
-	linkEPs map[string]*channel.Endpoint
+	linkEps map[tcpip.NICID]*channel.Endpoint
 	s       *stack.Stack
 
 	ep tcpip.Endpoint
@@ -66,27 +66,24 @@ func (c *testContext) createV6Endpoint(v6only bool) {
 	}
 }
 
-// newDualTestContextMultiNic creates the testing context and also linkEpNames
-// named NICs.
-func newDualTestContextMultiNic(t *testing.T, mtu uint32, linkEpNames []string) *testContext {
+// newDualTestContextMultiNIC creates the testing context and also linkEpIDs NICs.
+func newDualTestContextMultiNIC(t *testing.T, mtu uint32, linkEpIDs []tcpip.NICID) *testContext {
 	s := stack.New(stack.Options{
 		NetworkProtocols:   []stack.NetworkProtocol{ipv4.NewProtocol(), ipv6.NewProtocol()},
 		TransportProtocols: []stack.TransportProtocol{udp.NewProtocol()}})
-	linkEPs := make(map[string]*channel.Endpoint)
-	for i, linkEpName := range linkEpNames {
-		channelEP := channel.New(256, mtu, "")
-		nicID := tcpip.NICID(i + 1)
-		opts := stack.NICOptions{Name: linkEpName}
-		if err := s.CreateNICWithOptions(nicID, channelEP, opts); err != nil {
-			t.Fatalf("CreateNICWithOptions(_, _, %+v) failed: %v", opts, err)
+	linkEps := make(map[tcpip.NICID]*channel.Endpoint)
+	for _, linkEpID := range linkEpIDs {
+		channelEp := channel.New(256, mtu, "")
+		if err := s.CreateNIC(linkEpID, channelEp); err != nil {
+			t.Fatalf("CreateNIC failed: %v", err)
 		}
-		linkEPs[linkEpName] = channelEP
+		linkEps[linkEpID] = channelEp
 
-		if err := s.AddAddress(nicID, ipv4.ProtocolNumber, stackAddr); err != nil {
+		if err := s.AddAddress(linkEpID, ipv4.ProtocolNumber, stackAddr); err != nil {
 			t.Fatalf("AddAddress IPv4 failed: %v", err)
 		}
 
-		if err := s.AddAddress(nicID, ipv6.ProtocolNumber, stackV6Addr); err != nil {
+		if err := s.AddAddress(linkEpID, ipv6.ProtocolNumber, stackV6Addr); err != nil {
 			t.Fatalf("AddAddress IPv6 failed: %v", err)
 		}
 	}
@@ -105,7 +102,7 @@ func newDualTestContextMultiNic(t *testing.T, mtu uint32, linkEpNames []string)
 	return &testContext{
 		t:       t,
 		s:       s,
-		linkEPs: linkEPs,
+		linkEps: linkEps,
 	}
 }
 
@@ -122,7 +119,7 @@ func newPayload() []byte {
 	return b
 }
 
-func (c *testContext) sendV6Packet(payload []byte, h *headers, linkEpName string) {
+func (c *testContext) sendV6Packet(payload []byte, h *headers, linkEpID tcpip.NICID) {
 	// Allocate a buffer for data and headers.
 	buf := buffer.NewView(header.UDPMinimumSize + header.IPv6MinimumSize + len(payload))
 	copy(buf[len(buf)-len(payload):], payload)
@@ -153,7 +150,7 @@ func (c *testContext) sendV6Packet(payload []byte, h *headers, linkEpName string
 	u.SetChecksum(^u.CalculateChecksum(xsum))
 
 	// Inject packet.
-	c.linkEPs[linkEpName].InjectInbound(ipv6.ProtocolNumber, tcpip.PacketBuffer{
+	c.linkEps[linkEpID].InjectInbound(ipv6.ProtocolNumber, tcpip.PacketBuffer{
 		Data: buf.ToVectorisedView(),
 	})
 }
@@ -183,7 +180,7 @@ func TestTransportDemuxerRegister(t *testing.T) {
 func TestDistribution(t *testing.T) {
 	type endpointSockopts struct {
 		reuse        int
-		bindToDevice string
+		bindToDevice tcpip.NICID
 	}
 	for _, test := range []struct {
 		name string
@@ -191,71 +188,71 @@ func TestDistribution(t *testing.T) {
 		endpoints []endpointSockopts
 		// wantedDistribution is the wanted ratio of packets received on each
 		// endpoint for each NIC on which packets are injected.
-		wantedDistributions map[string][]float64
+		wantedDistributions map[tcpip.NICID][]float64
 	}{
 		{
 			"BindPortReuse",
 			// 5 endpoints that all have reuse set.
 			[]endpointSockopts{
-				{1, ""},
-				{1, ""},
-				{1, ""},
-				{1, ""},
-				{1, ""},
+				{1, 0},
+				{1, 0},
+				{1, 0},
+				{1, 0},
+				{1, 0},
 			},
-			map[string][]float64{
+			map[tcpip.NICID][]float64{
 				// Injected packets on dev0 get distributed evenly.
-				"dev0": {0.2, 0.2, 0.2, 0.2, 0.2},
+				1: {0.2, 0.2, 0.2, 0.2, 0.2},
 			},
 		},
 		{
 			"BindToDevice",
 			// 3 endpoints with various bindings.
 			[]endpointSockopts{
-				{0, "dev0"},
-				{0, "dev1"},
-				{0, "dev2"},
+				{0, 1},
+				{0, 2},
+				{0, 3},
 			},
-			map[string][]float64{
+			map[tcpip.NICID][]float64{
 				// Injected packets on dev0 go only to the endpoint bound to dev0.
-				"dev0": {1, 0, 0},
+				1: {1, 0, 0},
 				// Injected packets on dev1 go only to the endpoint bound to dev1.
-				"dev1": {0, 1, 0},
+				2: {0, 1, 0},
 				// Injected packets on dev2 go only to the endpoint bound to dev2.
-				"dev2": {0, 0, 1},
+				3: {0, 0, 1},
 			},
 		},
 		{
 			"ReuseAndBindToDevice",
 			// 6 endpoints with various bindings.
 			[]endpointSockopts{
-				{1, "dev0"},
-				{1, "dev0"},
-				{1, "dev1"},
-				{1, "dev1"},
-				{1, "dev1"},
-				{1, ""},
+				{1, 1},
+				{1, 1},
+				{1, 2},
+				{1, 2},
+				{1, 2},
+				{1, 0},
 			},
-			map[string][]float64{
+			map[tcpip.NICID][]float64{
 				// Injected packets on dev0 get distributed among endpoints bound to
 				// dev0.
-				"dev0": {0.5, 0.5, 0, 0, 0, 0},
+				1: {0.5, 0.5, 0, 0, 0, 0},
 				// Injected packets on dev1 get distributed among endpoints bound to
 				// dev1 or unbound.
-				"dev1": {0, 0, 1. / 3, 1. / 3, 1. / 3, 0},
+				2: {0, 0, 1. / 3, 1. / 3, 1. / 3, 0},
 				// Injected packets on dev999 go only to the unbound.
-				"dev999": {0, 0, 0, 0, 0, 1},
+				1000: {0, 0, 0, 0, 0, 1},
 			},
 		},
 	} {
 		t.Run(test.name, func(t *testing.T) {
 			for device, wantedDistribution := range test.wantedDistributions {
-				t.Run(device, func(t *testing.T) {
-					var devices []string
+				t.Run(string(device), func(t *testing.T) {
+					var devices []tcpip.NICID
 					for d := range test.wantedDistributions {
 						devices = append(devices, d)
 					}
-					c := newDualTestContextMultiNic(t, defaultMTU, devices)
+					c := newDualTestContextMultiNIC(t, defaultMTU, devices)
 					defer c.cleanup()
 
 					c.createV6Endpoint(false)
diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go
index 1eca76c30..72b5ce179 100644
--- a/pkg/tcpip/tcpip.go
+++ b/pkg/tcpip/tcpip.go
@@ -552,7 +552,7 @@ type ReusePortOption int
 
 // BindToDeviceOption is used by SetSockOpt/GetSockOpt to specify that sockets
 // should bind only on a specific NIC.
-type BindToDeviceOption string
+type BindToDeviceOption NICID
 
 // QuickAckOption is stubbed out in SetSockOpt/GetSockOpt.
 type QuickAckOption int
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index 2ac1b6877..920b24975 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -1279,19 +1279,14 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 		return nil
 
 	case tcpip.BindToDeviceOption:
-		e.mu.Lock()
-		defer e.mu.Unlock()
-		if v == "" {
-			e.bindToDevice = 0
-			return nil
-		}
-		for nicID, nic := range e.stack.NICInfo() {
-			if nic.Name == string(v) {
-				e.bindToDevice = nicID
-				return nil
-			}
+		id := tcpip.NICID(v)
+		if id != 0 && !e.stack.HasNIC(id) {
+			return tcpip.ErrUnknownDevice
 		}
-		return tcpip.ErrUnknownDevice
+		e.mu.Lock()
+		e.bindToDevice = id
+		e.mu.Unlock()
+		return nil
 
 	case tcpip.QuickAckOption:
 		if v == 0 {
@@ -1550,12 +1545,8 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 
 	case *tcpip.BindToDeviceOption:
 		e.mu.RLock()
-		defer e.mu.RUnlock()
-		if nic, ok := e.stack.NICInfo()[e.bindToDevice]; ok {
-			*o = tcpip.BindToDeviceOption(nic.Name)
-			return nil
-		}
-		*o = ""
+		*o = tcpip.BindToDeviceOption(e.bindToDevice)
+		e.mu.RUnlock()
 		return nil
 
 	case *tcpip.QuickAckOption:
diff --git a/pkg/tcpip/transport/tcp/tcp_test.go b/pkg/tcpip/transport/tcp/tcp_test.go
index 15745ebd4..1aa0733d0 100644
--- a/pkg/tcpip/transport/tcp/tcp_test.go
+++ b/pkg/tcpip/transport/tcp/tcp_test.go
@@ -1083,12 +1083,12 @@ func TestTrafficClassV6(t *testing.T) {
 func TestConnectBindToDevice(t *testing.T) {
 	for _, test := range []struct {
 		name   string
-		device string
+		device tcpip.NICID
 		want   tcp.EndpointState
 	}{
-		{"RightDevice", "nic1", tcp.StateEstablished},
-		{"WrongDevice", "nic2", tcp.StateSynSent},
-		{"AnyDevice", "", tcp.StateEstablished},
+		{"RightDevice", 1, tcp.StateEstablished},
+		{"WrongDevice", 2, tcp.StateSynSent},
+		{"AnyDevice", 0, tcp.StateEstablished},
 	} {
 		t.Run(test.name, func(t *testing.T) {
 			c := context.New(t, defaultMTU)
@@ -3794,47 +3794,41 @@ func TestBindToDeviceOption(t *testing.T) {
 	}
 	defer ep.Close()
 
-	opts := stack.NICOptions{Name: "my_device"}
-	if err := s.CreateNICWithOptions(321, loopback.New(), opts); err != nil {
-		t.Errorf("CreateNICWithOptions(_, _, %+v) failed: %v", opts, err)
-	}
-
-	// Make an nameless NIC.
-	if err := s.CreateNIC(54321, loopback.New()); err != nil {
+	if err := s.CreateNIC(321, loopback.New()); err != nil {
 		t.Errorf("CreateNIC failed: %v", err)
 	}
 
-	// strPtr is used instead of taking the address of string literals, which is
+	// nicIDPtr is used instead of taking the address of NICID literals, which is
 	// a compiler error.
-	strPtr := func(s string) *string {
+	nicIDPtr := func(s tcpip.NICID) *tcpip.NICID {
 		return &s
 	}
 
 	testActions := []struct {
 		name                 string
-		setBindToDevice      *string
+		setBindToDevice      *tcpip.NICID
 		setBindToDeviceError *tcpip.Error
 		getBindToDevice      tcpip.BindToDeviceOption
 	}{
-		{"GetDefaultValue", nil, nil, ""},
-		{"BindToNonExistent", strPtr("non_existent_device"), tcpip.ErrUnknownDevice, ""},
-		{"BindToExistent", strPtr("my_device"), nil, "my_device"},
-		{"UnbindToDevice", strPtr(""), nil, ""},
+		{"GetDefaultValue", nil, nil, 0},
+		{"BindToNonExistent", nicIDPtr(999), tcpip.ErrUnknownDevice, 0},
+		{"BindToExistent", nicIDPtr(321), nil, 321},
+		{"UnbindToDevice", nicIDPtr(0), nil, 0},
 	}
 	for _, testAction := range testActions {
 		t.Run(testAction.name, func(t *testing.T) {
 			if testAction.setBindToDevice != nil {
 				bindToDevice := tcpip.BindToDeviceOption(*testAction.setBindToDevice)
-				if got, want := ep.SetSockOpt(bindToDevice), testAction.setBindToDeviceError; got != want {
-					t.Errorf("SetSockOpt(%v) got %v, want %v", bindToDevice, got, want)
+				if gotErr, wantErr := ep.SetSockOpt(bindToDevice), testAction.setBindToDeviceError; gotErr != wantErr {
+					t.Errorf("SetSockOpt(%v) got %v, want %v", bindToDevice, gotErr, wantErr)
 				}
 			}
-			bindToDevice := tcpip.BindToDeviceOption("to be modified by GetSockOpt")
-			if ep.GetSockOpt(&bindToDevice) != nil {
-				t.Errorf("GetSockOpt got %v, want %v", ep.GetSockOpt(&bindToDevice), nil)
+			bindToDevice := tcpip.BindToDeviceOption(88888)
+			if err := ep.GetSockOpt(&bindToDevice); err != nil {
+				t.Errorf("GetSockOpt got %v, want %v", err, nil)
 			}
 			if got, want := bindToDevice, testAction.getBindToDevice; got != want {
-				t.Errorf("bindToDevice got %q, want %q", got, want)
+				t.Errorf("bindToDevice got %d, want %d", got, want)
 			}
 		})
 	}
diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go
index 1a5ee6317..864dc8733 100644
--- a/pkg/tcpip/transport/udp/endpoint.go
+++ b/pkg/tcpip/transport/udp/endpoint.go
@@ -631,19 +631,14 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 		e.mu.Unlock()
 
 	case tcpip.BindToDeviceOption:
-		e.mu.Lock()
-		defer e.mu.Unlock()
-		if v == "" {
-			e.bindToDevice = 0
-			return nil
-		}
-		for nicID, nic := range e.stack.NICInfo() {
-			if nic.Name == string(v) {
-				e.bindToDevice = nicID
-				return nil
-			}
+		id := tcpip.NICID(v)
+		if id != 0 && !e.stack.HasNIC(id) {
+			return tcpip.ErrUnknownDevice
 		}
-		return tcpip.ErrUnknownDevice
+		e.mu.Lock()
+		e.bindToDevice = id
+		e.mu.Unlock()
+		return nil
 
 	case tcpip.BroadcastOption:
 		e.mu.Lock()
@@ -767,12 +762,8 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 
 	case *tcpip.BindToDeviceOption:
 		e.mu.RLock()
-		defer e.mu.RUnlock()
-		if nic, ok := e.stack.NICInfo()[e.bindToDevice]; ok {
-			*o = tcpip.BindToDeviceOption(nic.Name)
-			return nil
-		}
-		*o = tcpip.BindToDeviceOption("")
+		*o = tcpip.BindToDeviceOption(e.bindToDevice)
+		e.mu.RUnlock()
 		return nil
 
 	case *tcpip.KeepaliveEnabledOption:
diff --git a/pkg/tcpip/transport/udp/udp_test.go b/pkg/tcpip/transport/udp/udp_test.go
index 149fff999..0a82bc4fa 100644
--- a/pkg/tcpip/transport/udp/udp_test.go
+++ b/pkg/tcpip/transport/udp/udp_test.go
@@ -513,42 +513,37 @@ func TestBindToDeviceOption(t *testing.T) {
 		t.Errorf("CreateNICWithOptions(_, _, %+v) failed: %v", opts, err)
 	}
 
-	// Make an nameless NIC.
-	if err := s.CreateNIC(54321, loopback.New()); err != nil {
-		t.Errorf("CreateNIC failed: %v", err)
-	}
-
-	// strPtr is used instead of taking the address of string literals, which is
+	// nicIDPtr is used instead of taking the address of NICID literals, which is
 	// a compiler error.
-	strPtr := func(s string) *string {
+	nicIDPtr := func(s tcpip.NICID) *tcpip.NICID {
 		return &s
 	}
 
 	testActions := []struct {
 		name                 string
-		setBindToDevice      *string
+		setBindToDevice      *tcpip.NICID
 		setBindToDeviceError *tcpip.Error
 		getBindToDevice      tcpip.BindToDeviceOption
 	}{
-		{"GetDefaultValue", nil, nil, ""},
-		{"BindToNonExistent", strPtr("non_existent_device"), tcpip.ErrUnknownDevice, ""},
-		{"BindToExistent", strPtr("my_device"), nil, "my_device"},
-		{"UnbindToDevice", strPtr(""), nil, ""},
+		{"GetDefaultValue", nil, nil, 0},
+		{"BindToNonExistent", nicIDPtr(999), tcpip.ErrUnknownDevice, 0},
+		{"BindToExistent", nicIDPtr(321), nil, 321},
+		{"UnbindToDevice", nicIDPtr(0), nil, 0},
 	}
 	for _, testAction := range testActions {
 		t.Run(testAction.name, func(t *testing.T) {
 			if testAction.setBindToDevice != nil {
 				bindToDevice := tcpip.BindToDeviceOption(*testAction.setBindToDevice)
-				if got, want := ep.SetSockOpt(bindToDevice), testAction.setBindToDeviceError; got != want {
-					t.Errorf("SetSockOpt(%v) got %v, want %v", bindToDevice, got, want)
+				if gotErr, wantErr := ep.SetSockOpt(bindToDevice), testAction.setBindToDeviceError; gotErr != wantErr {
+					t.Errorf("SetSockOpt(%v) got %v, want %v", bindToDevice, gotErr, wantErr)
 				}
 			}
-			bindToDevice := tcpip.BindToDeviceOption("to be modified by GetSockOpt")
-			if ep.GetSockOpt(&bindToDevice) != nil {
-				t.Errorf("GetSockOpt got %v, want %v", ep.GetSockOpt(&bindToDevice), nil)
+			bindToDevice := tcpip.BindToDeviceOption(88888)
+			if err := ep.GetSockOpt(&bindToDevice); err != nil {
+				t.Errorf("GetSockOpt got %v, want %v", err, nil)
 			}
 			if got, want := bindToDevice, testAction.getBindToDevice; got != want {
-				t.Errorf("bindToDevice got %q, want %q", got, want)
+				t.Errorf("bindToDevice got %d, want %d", got, want)
 			}
 		})
 	}
-- 
cgit v1.2.3


From 8fafd3142e85175fe56bc3333d859f1a8cfbb878 Mon Sep 17 00:00:00 2001
From: Ghanan Gowripalan <ghanan@google.com>
Date: Thu, 9 Jan 2020 15:55:24 -0800
Subject: Separate NDP tests into its own package

Internal tools timeout after 60s during tests that are required to pass before
changes can be submitted. Separate out NDP tests into its own package to help
prevent timeouts when testing.

PiperOrigin-RevId: 288990597
---
 pkg/tcpip/stack/BUILD         | 23 ++++++++++--
 pkg/tcpip/stack/ndp_test.go   | 87 +++++++++++++++++++++++++++++++++++++++----
 pkg/tcpip/stack/stack_test.go | 74 +++---------------------------------
 3 files changed, 106 insertions(+), 78 deletions(-)

diff --git a/pkg/tcpip/stack/BUILD b/pkg/tcpip/stack/BUILD
index b8f9517d0..826fca4de 100644
--- a/pkg/tcpip/stack/BUILD
+++ b/pkg/tcpip/stack/BUILD
@@ -52,7 +52,6 @@ go_test(
     name = "stack_x_test",
     size = "small",
     srcs = [
-        "ndp_test.go",
         "stack_test.go",
         "transport_demuxer_test.go",
         "transport_test.go",
@@ -62,14 +61,12 @@ go_test(
         "//pkg/rand",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
-        "//pkg/tcpip/checker",
         "//pkg/tcpip/header",
         "//pkg/tcpip/iptables",
         "//pkg/tcpip/link/channel",
         "//pkg/tcpip/link/loopback",
         "//pkg/tcpip/network/ipv4",
         "//pkg/tcpip/network/ipv6",
-        "//pkg/tcpip/transport/icmp",
         "//pkg/tcpip/transport/udp",
         "//pkg/waiter",
         "@com_github_google_go-cmp//cmp:go_default_library",
@@ -86,3 +83,23 @@ go_test(
         "//pkg/tcpip",
     ],
 )
+
+go_test(
+    name = "ndp_test",
+    size = "small",
+    srcs = ["ndp_test.go"],
+    deps = [
+        ":stack",
+        "//pkg/rand",
+        "//pkg/tcpip",
+        "//pkg/tcpip/buffer",
+        "//pkg/tcpip/checker",
+        "//pkg/tcpip/header",
+        "//pkg/tcpip/link/channel",
+        "//pkg/tcpip/network/ipv6",
+        "//pkg/tcpip/transport/icmp",
+        "//pkg/tcpip/transport/udp",
+        "//pkg/waiter",
+        "@com_github_google_go-cmp//cmp:go_default_library",
+    ],
+)
diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go
index d334af289..fa84c94a6 100644
--- a/pkg/tcpip/stack/ndp_test.go
+++ b/pkg/tcpip/stack/ndp_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package stack_test
+package ndp_test
 
 import (
 	"encoding/binary"
@@ -285,6 +285,8 @@ func (n *ndpDispatcher) OnRecursiveDNSServerOption(nicID tcpip.NICID, addrs []tc
 // Included in the subtests is a test to make sure that an invalid
 // RetransmitTimer (<1ms) values get fixed to the default RetransmitTimer of 1s.
 func TestDADResolve(t *testing.T) {
+	t.Parallel()
+
 	tests := []struct {
 		name                    string
 		dupAddrDetectTransmits  uint8
@@ -417,6 +419,8 @@ func TestDADResolve(t *testing.T) {
 // a node doing DAD for the same address), or if another node is detected to own
 // the address already (receive an NA message for the tentative address).
 func TestDADFail(t *testing.T) {
+	t.Parallel()
+
 	tests := []struct {
 		name    string
 		makeBuf func(tgt tcpip.Address) buffer.Prependable
@@ -560,6 +564,8 @@ func TestDADFail(t *testing.T) {
 // TestDADStop tests to make sure that the DAD process stops when an address is
 // removed.
 func TestDADStop(t *testing.T) {
+	t.Parallel()
+
 	ndpDisp := ndpDispatcher{
 		dadC: make(chan ndpDADEvent),
 	}
@@ -632,6 +638,71 @@ func TestDADStop(t *testing.T) {
 	}
 }
 
+// TestNICAutoGenAddrDoesDAD tests that the successful auto-generation of IPv6
+// link-local addresses will only be assigned after the DAD process resolves.
+func TestNICAutoGenAddrDoesDAD(t *testing.T) {
+	t.Parallel()
+
+	ndpDisp := ndpDispatcher{
+		dadC: make(chan ndpDADEvent),
+	}
+	ndpConfigs := stack.DefaultNDPConfigurations()
+	opts := stack.Options{
+		NetworkProtocols:     []stack.NetworkProtocol{ipv6.NewProtocol()},
+		NDPConfigs:           ndpConfigs,
+		AutoGenIPv6LinkLocal: true,
+		NDPDisp:              &ndpDisp,
+	}
+
+	e := channel.New(0, 1280, linkAddr1)
+	s := stack.New(opts)
+	if err := s.CreateNIC(1, e); err != nil {
+		t.Fatalf("CreateNIC(_) = %s", err)
+	}
+
+	// Address should not be considered bound to the
+	// NIC yet (DAD ongoing).
+	addr, err := s.GetMainNICAddress(1, header.IPv6ProtocolNumber)
+	if err != nil {
+		t.Fatalf("got stack.GetMainNICAddress(_, _) = (_, %v), want = (_, nil)", err)
+	}
+	if want := (tcpip.AddressWithPrefix{}); addr != want {
+		t.Fatalf("got stack.GetMainNICAddress(_, _) = (%s, nil), want = (%s, nil)", addr, want)
+	}
+
+	linkLocalAddr := header.LinkLocalAddr(linkAddr1)
+
+	// Wait for DAD to resolve.
+	select {
+	case <-time.After(time.Duration(ndpConfigs.DupAddrDetectTransmits)*ndpConfigs.RetransmitTimer + time.Second):
+		// We should get a resolution event after 1s (default time to
+		// resolve as per default NDP configurations). Waiting for that
+		// resolution time + an extra 1s without a resolution event
+		// means something is wrong.
+		t.Fatal("timed out waiting for DAD resolution")
+	case e := <-ndpDisp.dadC:
+		if e.err != nil {
+			t.Fatal("got DAD error: ", e.err)
+		}
+		if e.nicID != 1 {
+			t.Fatalf("got DAD event w/ nicID = %d, want = 1", e.nicID)
+		}
+		if e.addr != linkLocalAddr {
+			t.Fatalf("got DAD event w/ addr = %s, want = %s", addr, linkLocalAddr)
+		}
+		if !e.resolved {
+			t.Fatal("got DAD event w/ resolved = false, want = true")
+		}
+	}
+	addr, err = s.GetMainNICAddress(1, header.IPv6ProtocolNumber)
+	if err != nil {
+		t.Fatalf("stack.GetMainNICAddress(_, _) err = %s", err)
+	}
+	if want := (tcpip.AddressWithPrefix{Address: linkLocalAddr, PrefixLen: header.IPv6LinkLocalPrefix.PrefixLen}); addr != want {
+		t.Fatalf("got stack.GetMainNICAddress(_, _) = %s, want = %s", addr, want)
+	}
+}
+
 // TestSetNDPConfigurationFailsForBadNICID tests to make sure we get an error if
 // we attempt to update NDP configurations using an invalid NICID.
 func TestSetNDPConfigurationFailsForBadNICID(t *testing.T) {
@@ -649,6 +720,8 @@ func TestSetNDPConfigurationFailsForBadNICID(t *testing.T) {
 // configurations without affecting the default NDP configurations or other
 // interfaces' configurations.
 func TestSetNDPConfigurations(t *testing.T) {
+	t.Parallel()
+
 	tests := []struct {
 		name                    string
 		dupAddrDetectTransmits  uint8
@@ -875,6 +948,8 @@ func raBufWithPI(ip tcpip.Address, rl uint16, prefix tcpip.AddressWithPrefix, on
 // TestNoRouterDiscovery tests that router discovery will not be performed if
 // configured not to.
 func TestNoRouterDiscovery(t *testing.T) {
+	t.Parallel()
+
 	// Being configured to discover routers means handle and
 	// discover are set to true and forwarding is set to false.
 	// This tests all possible combinations of the configurations,
@@ -887,8 +962,6 @@ func TestNoRouterDiscovery(t *testing.T) {
 		forwarding := i&4 == 0
 
 		t.Run(fmt.Sprintf("HandleRAs(%t), DiscoverDefaultRouters(%t), Forwarding(%t)", handle, discover, forwarding), func(t *testing.T) {
-			t.Parallel()
-
 			ndpDisp := ndpDispatcher{
 				routerC: make(chan ndpRouterEvent, 1),
 			}
@@ -1123,6 +1196,8 @@ func TestRouterDiscoveryMaxRouters(t *testing.T) {
 // TestNoPrefixDiscovery tests that prefix discovery will not be performed if
 // configured not to.
 func TestNoPrefixDiscovery(t *testing.T) {
+	t.Parallel()
+
 	prefix := tcpip.AddressWithPrefix{
 		Address:   tcpip.Address("\x01\x02\x03\x04\x05\x06\x07\x08\x00\x00\x00\x00\x00\x00\x00\x00"),
 		PrefixLen: 64,
@@ -1140,8 +1215,6 @@ func TestNoPrefixDiscovery(t *testing.T) {
 		forwarding := i&4 == 0
 
 		t.Run(fmt.Sprintf("HandleRAs(%t), DiscoverOnLinkPrefixes(%t), Forwarding(%t)", handle, discover, forwarding), func(t *testing.T) {
-			t.Parallel()
-
 			ndpDisp := ndpDispatcher{
 				prefixC: make(chan ndpPrefixEvent, 1),
 			}
@@ -1498,6 +1571,8 @@ func contains(list []tcpip.ProtocolAddress, item tcpip.AddressWithPrefix) bool {
 
 // TestNoAutoGenAddr tests that SLAAC is not performed when configured not to.
 func TestNoAutoGenAddr(t *testing.T) {
+	t.Parallel()
+
 	prefix, _, _ := prefixSubnetAddr(0, "")
 
 	// Being configured to auto-generate addresses means handle and
@@ -1512,8 +1587,6 @@ func TestNoAutoGenAddr(t *testing.T) {
 		forwarding := i&4 == 0
 
 		t.Run(fmt.Sprintf("HandleRAs(%t), AutoGenAddr(%t), Forwarding(%t)", handle, autogen, forwarding), func(t *testing.T) {
-			t.Parallel()
-
 			ndpDisp := ndpDispatcher{
 				autoGenAddrC: make(chan ndpAutoGenAddrEvent, 1),
 			}
diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go
index 44e5229cc..e8de4e87d 100644
--- a/pkg/tcpip/stack/stack_test.go
+++ b/pkg/tcpip/stack/stack_test.go
@@ -24,7 +24,6 @@ import (
 	"sort"
 	"strings"
 	"testing"
-	"time"
 
 	"github.com/google/go-cmp/cmp"
 	"gvisor.dev/gvisor/pkg/rand"
@@ -50,6 +49,8 @@ const (
 	// where another value is explicitly used. It is chosen to match the MTU
 	// of loopback interfaces on linux systems.
 	defaultMTU = 65536
+
+	linkAddr = "\x02\x02\x03\x04\x05\x06"
 )
 
 // fakeNetworkEndpoint is a network-layer protocol endpoint. It counts sent and
@@ -1909,7 +1910,7 @@ func TestNICAutoGenAddr(t *testing.T) {
 		{
 			"Disabled",
 			false,
-			linkAddr1,
+			linkAddr,
 			stack.OpaqueInterfaceIdentifierOptions{
 				NICNameFromID: func(nicID tcpip.NICID, _ string) string {
 					return fmt.Sprintf("nic%d", nicID)
@@ -1920,7 +1921,7 @@ func TestNICAutoGenAddr(t *testing.T) {
 		{
 			"Enabled",
 			true,
-			linkAddr1,
+			linkAddr,
 			stack.OpaqueInterfaceIdentifierOptions{},
 			true,
 		},
@@ -2068,14 +2069,14 @@ func TestNICAutoGenAddrWithOpaque(t *testing.T) {
 			name:      "Disabled",
 			nicName:   "nic1",
 			autoGen:   false,
-			linkAddr:  linkAddr1,
+			linkAddr:  linkAddr,
 			secretKey: secretKey[:],
 		},
 		{
 			name:      "Enabled",
 			nicName:   "nic1",
 			autoGen:   true,
-			linkAddr:  linkAddr1,
+			linkAddr:  linkAddr,
 			secretKey: secretKey[:],
 		},
 		// These are all cases where we would not have generated a
@@ -2213,69 +2214,6 @@ func TestNoLinkLocalAutoGenForLoopbackNIC(t *testing.T) {
 	}
 }
 
-// TestNICAutoGenAddrDoesDAD tests that the successful auto-generation of IPv6
-// link-local addresses will only be assigned after the DAD process resolves.
-func TestNICAutoGenAddrDoesDAD(t *testing.T) {
-	ndpDisp := ndpDispatcher{
-		dadC: make(chan ndpDADEvent),
-	}
-	ndpConfigs := stack.DefaultNDPConfigurations()
-	opts := stack.Options{
-		NetworkProtocols:     []stack.NetworkProtocol{ipv6.NewProtocol()},
-		NDPConfigs:           ndpConfigs,
-		AutoGenIPv6LinkLocal: true,
-		NDPDisp:              &ndpDisp,
-	}
-
-	e := channel.New(10, 1280, linkAddr1)
-	s := stack.New(opts)
-	if err := s.CreateNIC(1, e); err != nil {
-		t.Fatalf("CreateNIC(_) = %s", err)
-	}
-
-	// Address should not be considered bound to the
-	// NIC yet (DAD ongoing).
-	addr, err := s.GetMainNICAddress(1, header.IPv6ProtocolNumber)
-	if err != nil {
-		t.Fatalf("got stack.GetMainNICAddress(_, _) = (_, %v), want = (_, nil)", err)
-	}
-	if want := (tcpip.AddressWithPrefix{}); addr != want {
-		t.Fatalf("got stack.GetMainNICAddress(_, _) = (%s, nil), want = (%s, nil)", addr, want)
-	}
-
-	linkLocalAddr := header.LinkLocalAddr(linkAddr1)
-
-	// Wait for DAD to resolve.
-	select {
-	case <-time.After(time.Duration(ndpConfigs.DupAddrDetectTransmits)*ndpConfigs.RetransmitTimer + time.Second):
-		// We should get a resolution event after 1s (default time to
-		// resolve as per default NDP configurations). Waiting for that
-		// resolution time + an extra 1s without a resolution event
-		// means something is wrong.
-		t.Fatal("timed out waiting for DAD resolution")
-	case e := <-ndpDisp.dadC:
-		if e.err != nil {
-			t.Fatal("got DAD error: ", e.err)
-		}
-		if e.nicID != 1 {
-			t.Fatalf("got DAD event w/ nicID = %d, want = 1", e.nicID)
-		}
-		if e.addr != linkLocalAddr {
-			t.Fatalf("got DAD event w/ addr = %s, want = %s", addr, linkLocalAddr)
-		}
-		if !e.resolved {
-			t.Fatal("got DAD event w/ resolved = false, want = true")
-		}
-	}
-	addr, err = s.GetMainNICAddress(1, header.IPv6ProtocolNumber)
-	if err != nil {
-		t.Fatalf("stack.GetMainNICAddress(_, _) err = %s", err)
-	}
-	if want := (tcpip.AddressWithPrefix{Address: linkLocalAddr, PrefixLen: header.IPv6LinkLocalPrefix.PrefixLen}); addr != want {
-		t.Fatalf("got stack.GetMainNICAddress(_, _) = %s, want = %s", addr, want)
-	}
-}
-
 // TestNewPEB tests that a new PrimaryEndpointBehavior value (peb) is respected
 // when an address's kind gets "promoted" to permanent from permanentExpired.
 func TestNewPEBOnPromotionToPermanent(t *testing.T) {
-- 
cgit v1.2.3


From 26c5653bb547450e85666f345d542b516b3417fc Mon Sep 17 00:00:00 2001
From: Ghanan Gowripalan <ghanan@google.com>
Date: Thu, 9 Jan 2020 16:55:01 -0800
Subject: Inform NDPDispatcher when Stack learns about available configurations
 via DHCPv6

Inform the Stack's NDPDispatcher when it receives an NDP Router Advertisement
that updates the available configurations via DHCPv6. The Stack makes sure that
its NDPDispatcher isn't informed unless the avaiable configurations via DHCPv6
for a NIC is updated.

Tests: Test that a Stack's NDPDispatcher is informed when it receives an NDP
Router Advertisement that informs it of new configurations available via DHCPv6.
PiperOrigin-RevId: 289001283
---
 pkg/tcpip/stack/ndp.go      |  62 +++++++++++++++++
 pkg/tcpip/stack/ndp_test.go | 165 ++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 212 insertions(+), 15 deletions(-)

diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go
index 35825ebf7..a9dd322db 100644
--- a/pkg/tcpip/stack/ndp.go
+++ b/pkg/tcpip/stack/ndp.go
@@ -115,6 +115,30 @@ var (
 	MinPrefixInformationValidLifetimeForUpdate = 2 * time.Hour
 )
 
+// DHCPv6ConfigurationFromNDPRA is a configuration available via DHCPv6 that an
+// NDP Router Advertisement informed the Stack about.
+type DHCPv6ConfigurationFromNDPRA int
+
+const (
+	// DHCPv6NoConfiguration indicates that no configurations are available via
+	// DHCPv6.
+	DHCPv6NoConfiguration DHCPv6ConfigurationFromNDPRA = iota
+
+	// DHCPv6ManagedAddress indicates that addresses are available via DHCPv6.
+	//
+	// DHCPv6ManagedAddress also implies DHCPv6OtherConfigurations because DHCPv6
+	// will return all available configuration information.
+	DHCPv6ManagedAddress
+
+	// DHCPv6OtherConfigurations indicates that other configuration information is
+	// available via DHCPv6.
+	//
+	// Other configurations are configurations other than addresses. Examples of
+	// other configurations are recursive DNS server list, DNS search lists and
+	// default gateway.
+	DHCPv6OtherConfigurations
+)
+
 // NDPDispatcher is the interface integrators of netstack must implement to
 // receive and handle NDP related events.
 type NDPDispatcher interface {
@@ -194,7 +218,20 @@ type NDPDispatcher interface {
 	// already known DNS servers. If called with known DNS servers, their
 	// valid lifetimes must be refreshed to lifetime (it may be increased,
 	// decreased, or completely invalidated when lifetime = 0).
+	//
+	// This function is not permitted to block indefinitely. It must not
+	// call functions on the stack itself.
 	OnRecursiveDNSServerOption(nicID tcpip.NICID, addrs []tcpip.Address, lifetime time.Duration)
+
+	// OnDHCPv6Configuration will be called with an updated configuration that is
+	// available via DHCPv6 for a specified NIC.
+	//
+	// NDPDispatcher assumes that the initial configuration available by DHCPv6 is
+	// DHCPv6NoConfiguration.
+	//
+	// This function is not permitted to block indefinitely. It must not
+	// call functions on the stack itself.
+	OnDHCPv6Configuration(tcpip.NICID, DHCPv6ConfigurationFromNDPRA)
 }
 
 // NDPConfigurations is the NDP configurations for the netstack.
@@ -281,6 +318,9 @@ type ndpState struct {
 
 	// The addresses generated by SLAAC.
 	autoGenAddresses map[tcpip.Address]autoGenAddressState
+
+	// The last learned DHCPv6 configuration from an NDP RA.
+	dhcpv6Configuration DHCPv6ConfigurationFromNDPRA
 }
 
 // dadState holds the Duplicate Address Detection timer and channel to signal
@@ -533,6 +573,28 @@ func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) {
 		return
 	}
 
+	// Only worry about the DHCPv6 configuration if we have an NDPDispatcher as we
+	// only inform the dispatcher on configuration changes. We do nothing else
+	// with the information.
+	if ndpDisp := ndp.nic.stack.ndpDisp; ndpDisp != nil {
+		var configuration DHCPv6ConfigurationFromNDPRA
+		switch {
+		case ra.ManagedAddrConfFlag():
+			configuration = DHCPv6ManagedAddress
+
+		case ra.OtherConfFlag():
+			configuration = DHCPv6OtherConfigurations
+
+		default:
+			configuration = DHCPv6NoConfiguration
+		}
+
+		if ndp.dhcpv6Configuration != configuration {
+			ndp.dhcpv6Configuration = configuration
+			ndpDisp.OnDHCPv6Configuration(ndp.nic.ID(), configuration)
+		}
+	}
+
 	// Is the NIC configured to discover default routers?
 	if ndp.configs.DiscoverDefaultRouters {
 		rtr, ok := ndp.defaultRouters[ip]
diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go
index fa84c94a6..108762b6e 100644
--- a/pkg/tcpip/stack/ndp_test.go
+++ b/pkg/tcpip/stack/ndp_test.go
@@ -162,18 +162,24 @@ type ndpRDNSSEvent struct {
 	rdnss ndpRDNSS
 }
 
+type ndpDHCPv6Event struct {
+	nicID         tcpip.NICID
+	configuration stack.DHCPv6ConfigurationFromNDPRA
+}
+
 var _ stack.NDPDispatcher = (*ndpDispatcher)(nil)
 
 // ndpDispatcher implements NDPDispatcher so tests can know when various NDP
 // related events happen for test purposes.
 type ndpDispatcher struct {
-	dadC           chan ndpDADEvent
-	routerC        chan ndpRouterEvent
-	rememberRouter bool
-	prefixC        chan ndpPrefixEvent
-	rememberPrefix bool
-	autoGenAddrC   chan ndpAutoGenAddrEvent
-	rdnssC         chan ndpRDNSSEvent
+	dadC                 chan ndpDADEvent
+	routerC              chan ndpRouterEvent
+	rememberRouter       bool
+	prefixC              chan ndpPrefixEvent
+	rememberPrefix       bool
+	autoGenAddrC         chan ndpAutoGenAddrEvent
+	rdnssC               chan ndpRDNSSEvent
+	dhcpv6ConfigurationC chan ndpDHCPv6Event
 }
 
 // Implements stack.NDPDispatcher.OnDuplicateAddressDetectionStatus.
@@ -280,6 +286,16 @@ func (n *ndpDispatcher) OnRecursiveDNSServerOption(nicID tcpip.NICID, addrs []tc
 	}
 }
 
+// Implements stack.NDPDispatcher.OnDHCPv6Configuration.
+func (n *ndpDispatcher) OnDHCPv6Configuration(nicID tcpip.NICID, configuration stack.DHCPv6ConfigurationFromNDPRA) {
+	if c := n.dhcpv6ConfigurationC; c != nil {
+		c <- ndpDHCPv6Event{
+			nicID,
+			configuration,
+		}
+	}
+}
+
 // TestDADResolve tests that an address successfully resolves after performing
 // DAD for various values of DupAddrDetectTransmits and RetransmitTimer.
 // Included in the subtests is a test to make sure that an invalid
@@ -870,21 +886,32 @@ func TestSetNDPConfigurations(t *testing.T) {
 	}
 }
 
-// raBufWithOpts returns a valid NDP Router Advertisement with options.
-//
-// Note, raBufWithOpts does not populate any of the RA fields other than the
-// Router Lifetime.
-func raBufWithOpts(ip tcpip.Address, rl uint16, optSer header.NDPOptionsSerializer) tcpip.PacketBuffer {
+// raBufWithOptsAndDHCPv6 returns a valid NDP Router Advertisement with options
+// and DHCPv6 configurations specified.
+func raBufWithOptsAndDHCPv6(ip tcpip.Address, rl uint16, managedAddress, otherConfigurations bool, optSer header.NDPOptionsSerializer) tcpip.PacketBuffer {
 	icmpSize := header.ICMPv6HeaderSize + header.NDPRAMinimumSize + int(optSer.Length())
 	hdr := buffer.NewPrependable(header.IPv6MinimumSize + icmpSize)
 	pkt := header.ICMPv6(hdr.Prepend(icmpSize))
 	pkt.SetType(header.ICMPv6RouterAdvert)
 	pkt.SetCode(0)
-	ra := header.NDPRouterAdvert(pkt.NDPPayload())
+	raPayload := pkt.NDPPayload()
+	ra := header.NDPRouterAdvert(raPayload)
+	// Populate the Router Lifetime.
+	binary.BigEndian.PutUint16(raPayload[2:], rl)
+	// Populate the Managed Address flag field.
+	if managedAddress {
+		// The Managed Addresses flag field is the 7th bit of byte #1 (0-indexing)
+		// of the RA payload.
+		raPayload[1] |= (1 << 7)
+	}
+	// Populate the Other Configurations flag field.
+	if otherConfigurations {
+		// The Other Configurations flag field is the 6th bit of byte #1
+		// (0-indexing) of the RA payload.
+		raPayload[1] |= (1 << 6)
+	}
 	opts := ra.Options()
 	opts.Serialize(optSer)
-	// Populate the Router Lifetime.
-	binary.BigEndian.PutUint16(pkt.NDPPayload()[2:], rl)
 	pkt.SetChecksum(header.ICMPv6Checksum(pkt, ip, header.IPv6AllNodesMulticastAddress, buffer.VectorisedView{}))
 	payloadLength := hdr.UsedLength()
 	iph := header.IPv6(hdr.Prepend(header.IPv6MinimumSize))
@@ -899,6 +926,23 @@ func raBufWithOpts(ip tcpip.Address, rl uint16, optSer header.NDPOptionsSerializ
 	return tcpip.PacketBuffer{Data: hdr.View().ToVectorisedView()}
 }
 
+// raBufWithOpts returns a valid NDP Router Advertisement with options.
+//
+// Note, raBufWithOpts does not populate any of the RA fields other than the
+// Router Lifetime.
+func raBufWithOpts(ip tcpip.Address, rl uint16, optSer header.NDPOptionsSerializer) tcpip.PacketBuffer {
+	return raBufWithOptsAndDHCPv6(ip, rl, false, false, optSer)
+}
+
+// raBufWithDHCPv6 returns a valid NDP Router Advertisement with DHCPv6 related
+// fields set.
+//
+// Note, raBufWithDHCPv6 does not populate any of the RA fields other than the
+// DHCPv6 related ones.
+func raBufWithDHCPv6(ip tcpip.Address, managedAddresses, otherConfiguratiosns bool) tcpip.PacketBuffer {
+	return raBufWithOptsAndDHCPv6(ip, 0, managedAddresses, otherConfiguratiosns, header.NDPOptionsSerializer{})
+}
+
 // raBuf returns a valid NDP Router Advertisement.
 //
 // Note, raBuf does not populate any of the RA fields other than the
@@ -3024,3 +3068,94 @@ func TestCleanupHostOnlyStateOnBecomingRouter(t *testing.T) {
 	default:
 	}
 }
+
+// TestDHCPv6ConfigurationFromNDPDA tests that the NDPDispatcher is properly
+// informed when new information about what configurations are available via
+// DHCPv6 is learned.
+func TestDHCPv6ConfigurationFromNDPDA(t *testing.T) {
+	const nicID = 1
+
+	ndpDisp := ndpDispatcher{
+		dhcpv6ConfigurationC: make(chan ndpDHCPv6Event, 1),
+		rememberRouter:       true,
+	}
+	e := channel.New(0, 1280, linkAddr1)
+	s := stack.New(stack.Options{
+		NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()},
+		NDPConfigs: stack.NDPConfigurations{
+			HandleRAs: true,
+		},
+		NDPDisp: &ndpDisp,
+	})
+
+	if err := s.CreateNIC(nicID, e); err != nil {
+		t.Fatalf("CreateNIC(%d, _) = %s", nicID, err)
+	}
+
+	expectDHCPv6Event := func(configuration stack.DHCPv6ConfigurationFromNDPRA) {
+		t.Helper()
+		select {
+		case e := <-ndpDisp.dhcpv6ConfigurationC:
+			if diff := cmp.Diff(ndpDHCPv6Event{nicID: nicID, configuration: configuration}, e, cmp.AllowUnexported(e)); diff != "" {
+				t.Errorf("dhcpv6 event mismatch (-want +got):\n%s", diff)
+			}
+		default:
+			t.Fatal("expected DHCPv6 configuration event")
+		}
+	}
+
+	expectNoDHCPv6Event := func() {
+		t.Helper()
+		select {
+		case <-ndpDisp.dhcpv6ConfigurationC:
+			t.Fatal("unexpected DHCPv6 configuration event")
+		default:
+		}
+	}
+
+	// The initial DHCPv6 configuration should be stack.DHCPv6NoConfiguration.
+	e.InjectInbound(header.IPv6ProtocolNumber, raBufWithDHCPv6(llAddr2, false, false))
+	expectNoDHCPv6Event()
+
+	// Receive an RA that updates the DHCPv6 configuration to Other
+	// Configurations.
+	e.InjectInbound(header.IPv6ProtocolNumber, raBufWithDHCPv6(llAddr2, false, true))
+	expectDHCPv6Event(stack.DHCPv6OtherConfigurations)
+	// Receiving the same update again should not result in an event to the
+	// NDPDispatcher.
+	e.InjectInbound(header.IPv6ProtocolNumber, raBufWithDHCPv6(llAddr2, false, true))
+	expectNoDHCPv6Event()
+
+	// Receive an RA that updates the DHCPv6 configuration to Managed Address.
+	e.InjectInbound(header.IPv6ProtocolNumber, raBufWithDHCPv6(llAddr2, true, false))
+	expectDHCPv6Event(stack.DHCPv6ManagedAddress)
+	e.InjectInbound(header.IPv6ProtocolNumber, raBufWithDHCPv6(llAddr2, true, false))
+	expectNoDHCPv6Event()
+
+	// Receive an RA that updates the DHCPv6 configuration to none.
+	e.InjectInbound(header.IPv6ProtocolNumber, raBufWithDHCPv6(llAddr2, false, false))
+	expectDHCPv6Event(stack.DHCPv6NoConfiguration)
+	e.InjectInbound(header.IPv6ProtocolNumber, raBufWithDHCPv6(llAddr2, false, false))
+	expectNoDHCPv6Event()
+
+	// Receive an RA that updates the DHCPv6 configuration to Managed Address.
+	//
+	// Note, when the M flag is set, the O flag is redundant.
+	e.InjectInbound(header.IPv6ProtocolNumber, raBufWithDHCPv6(llAddr2, true, true))
+	expectDHCPv6Event(stack.DHCPv6ManagedAddress)
+	e.InjectInbound(header.IPv6ProtocolNumber, raBufWithDHCPv6(llAddr2, true, true))
+	expectNoDHCPv6Event()
+	// Even though the DHCPv6 flags are different, the effective configuration is
+	// the same so we should not receive a new event.
+	e.InjectInbound(header.IPv6ProtocolNumber, raBufWithDHCPv6(llAddr2, true, false))
+	expectNoDHCPv6Event()
+	e.InjectInbound(header.IPv6ProtocolNumber, raBufWithDHCPv6(llAddr2, true, true))
+	expectNoDHCPv6Event()
+
+	// Receive an RA that updates the DHCPv6 configuration to Other
+	// Configurations.
+	e.InjectInbound(header.IPv6ProtocolNumber, raBufWithDHCPv6(llAddr2, false, true))
+	expectDHCPv6Event(stack.DHCPv6OtherConfigurations)
+	e.InjectInbound(header.IPv6ProtocolNumber, raBufWithDHCPv6(llAddr2, false, true))
+	expectNoDHCPv6Event()
+}
-- 
cgit v1.2.3


From f1b69b159f440b93845c11192fcf1c7633d2b6c8 Mon Sep 17 00:00:00 2001
From: Zach Koopmans <zkoopmans@google.com>
Date: Thu, 9 Jan 2020 17:22:48 -0800
Subject: Implement gcloud_producer for bm-tools

bm-tools works via "Machine" objects, which are front
objects for actual virtual or physical machines. glcoud_producer
produces machines on GCP using the `gcloud` tool.

Included are:
- GCloudProducer - the class producing machines
- MockGCloudProducer - class for mocking GCloudProducer.
- tests using the mock
- test data as .json files. Code to generate this test data may be
included in a follow up.

PiperOrigin-RevId: 289005958
---
 benchmarks/BUILD                                   |   1 +
 benchmarks/harness/BUILD                           |   5 +-
 benchmarks/harness/machine_producers/BUILD         |  40 ++++
 .../harness/machine_producers/gcloud_producer.py   | 250 +++++++++++++++++++++
 .../machine_producers/gcloud_producer_test.py      |  48 ++++
 .../harness/machine_producers/mock_producer.py     |  23 +-
 .../machine_producers/testdata/get_five.json       | 211 +++++++++++++++++
 .../machine_producers/testdata/get_one.json        | 145 ++++++++++++
 8 files changed, 721 insertions(+), 2 deletions(-)
 create mode 100644 benchmarks/harness/machine_producers/gcloud_producer.py
 create mode 100644 benchmarks/harness/machine_producers/gcloud_producer_test.py
 create mode 100644 benchmarks/harness/machine_producers/testdata/get_five.json
 create mode 100644 benchmarks/harness/machine_producers/testdata/get_one.json

diff --git a/benchmarks/BUILD b/benchmarks/BUILD
index dbadeeaf2..1455c6c5b 100644
--- a/benchmarks/BUILD
+++ b/benchmarks/BUILD
@@ -5,5 +5,6 @@ py_binary(
     srcs = ["run.py"],
     main = "run.py",
     python_version = "PY3",
+    srcs_version = "PY3",
     deps = ["//benchmarks/runner"],
 )
diff --git a/benchmarks/harness/BUILD b/benchmarks/harness/BUILD
index 9546220c4..081a74243 100644
--- a/benchmarks/harness/BUILD
+++ b/benchmarks/harness/BUILD
@@ -24,6 +24,7 @@ py_library(
     name = "container",
     srcs = ["container.py"],
     deps = [
+        "//benchmarks/workloads",
         requirement("asn1crypto", False),
         requirement("chardet", False),
         requirement("certifi", False),
@@ -45,6 +46,7 @@ py_library(
         "//benchmarks/harness:container",
         "//benchmarks/harness:ssh_connection",
         "//benchmarks/harness:tunnel_dispatcher",
+        "//benchmarks/harness/machine_mocks",
         requirement("asn1crypto", False),
         requirement("chardet", False),
         requirement("certifi", False),
@@ -53,6 +55,7 @@ py_library(
         requirement("idna", False),
         requirement("ptyprocess", False),
         requirement("requests", False),
+        requirement("six", False),
         requirement("urllib3", False),
         requirement("websocket-client", False),
     ],
@@ -64,7 +67,7 @@ py_library(
     deps = [
         "//benchmarks/harness",
         requirement("bcrypt", False),
-        requirement("cffi", False),
+        requirement("cffi", True),
         requirement("paramiko", True),
         requirement("cryptography", False),
     ],
diff --git a/benchmarks/harness/machine_producers/BUILD b/benchmarks/harness/machine_producers/BUILD
index a48da02a1..c4e943882 100644
--- a/benchmarks/harness/machine_producers/BUILD
+++ b/benchmarks/harness/machine_producers/BUILD
@@ -20,6 +20,7 @@ py_library(
     srcs = ["mock_producer.py"],
     deps = [
         "//benchmarks/harness:machine",
+        "//benchmarks/harness/machine_producers:gcloud_producer",
         "//benchmarks/harness/machine_producers:machine_producer",
     ],
 )
@@ -38,3 +39,42 @@ py_library(
     name = "gcloud_mock_recorder",
     srcs = ["gcloud_mock_recorder.py"],
 )
+
+py_library(
+    name = "gcloud_producer",
+    srcs = ["gcloud_producer.py"],
+    deps = [
+        "//benchmarks/harness:machine",
+        "//benchmarks/harness/machine_producers:gcloud_mock_recorder",
+        "//benchmarks/harness/machine_producers:machine_producer",
+    ],
+)
+
+filegroup(
+    name = "test_data",
+    srcs = [
+        "testdata/get_five.json",
+        "testdata/get_one.json",
+    ],
+)
+
+py_library(
+    name = "gcloud_producer_test_lib",
+    srcs = ["gcloud_producer_test.py"],
+    deps = [
+        "//benchmarks/harness/machine_producers:machine_producer",
+        "//benchmarks/harness/machine_producers:mock_producer",
+    ],
+)
+
+py_test(
+    name = "gcloud_producer_test",
+    srcs = [":gcloud_producer_test_lib"],
+    data = [
+        ":test_data",
+    ],
+    python_version = "PY3",
+    tags = [
+        "local",
+    ],
+)
diff --git a/benchmarks/harness/machine_producers/gcloud_producer.py b/benchmarks/harness/machine_producers/gcloud_producer.py
new file mode 100644
index 000000000..4693dd8a2
--- /dev/null
+++ b/benchmarks/harness/machine_producers/gcloud_producer.py
@@ -0,0 +1,250 @@
+# python3
+# Copyright 2019 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""A machine producer which produces machine objects using `gcloud`.
+
+Machine producers produce valid harness.Machine objects which are backed by
+real machines. This producer produces those machines on the given user's GCP
+account using the `gcloud` tool.
+
+GCloudProducer creates instances on the given GCP account named like:
+`machine-XXXXXXX-XXXX-XXXX-XXXXXXXXXXXX` in a randomized fashion such that name
+collisions with user instances shouldn't happen.
+
+  Typical usage example:
+
+  producer = GCloudProducer(args)
+  machines = producer.get_machines(NUM_MACHINES)
+  # run stuff on machines with machines[i].run(CMD)
+  producer.release_machines(NUM_MACHINES)
+"""
+import datetime
+import getpass
+import json
+import subprocess
+import threading
+from typing import List, Dict, Any
+import uuid
+
+from benchmarks.harness import machine
+from benchmarks.harness.machine_producers import gcloud_mock_recorder
+from benchmarks.harness.machine_producers import machine_producer
+
+DEFAULT_USER = getpass.getuser()
+
+
+class GCloudProducer(machine_producer.MachineProducer):
+  """Implementation of MachineProducer backed by GCP.
+
+  Produces Machine objects backed by GCP instances.
+
+  Attributes:
+    project: The GCP project name under which to create the machines.
+    ssh_key_path: path to a valid ssh key. See README on vaild ssh keys.
+    image: image name as a string.
+    image_project: image project as a string.
+    zone: string to a valid GCP zone.
+    ssh_user: string of user name for ssh_key
+    ssh_password: string of password for ssh key
+    mock: a mock printer which will print mock data if required. Mock data is
+      recorded output from subprocess calls (returncode, stdout, args).
+    condition: mutex for this class around machine creation and deleteion.
+  """
+
+  def __init__(self,
+               project: str,
+               ssh_key_path: str,
+               image: str,
+               image_project: str,
+               zone: str,
+               ssh_user: str,
+               mock: gcloud_mock_recorder.MockPrinter = None):
+    self.project = project
+    self.ssh_key_path = ssh_key_path
+    self.image = image
+    self.image_project = image_project
+    self.zone = zone
+    self.ssh_user = ssh_user if ssh_user else DEFAULT_USER
+    self.mock = mock
+    self.condition = threading.Condition()
+
+  def get_machines(self, num_machines: int) -> List[machine.Machine]:
+    """Returns requested number of machines backed by GCP instances."""
+    if num_machines <= 0:
+      raise ValueError(
+          "Cannot ask for {num} machines!".format(num=num_machines))
+    with self.condition:
+      names = self._get_unique_names(num_machines)
+      self._build_instances(names)
+      instances = self._start_command(names)
+      self._add_ssh_key_to_instances(names)
+      return self._machines_from_instances(instances)
+
+  def release_machines(self, machine_list: List[machine.Machine]):
+    """Releases the requested number of machines, deleting the instances."""
+    if not machine_list:
+      return
+    with self.condition:
+      cmd = "gcloud compute instances delete --quiet".split(" ")
+      names = [str(m) for m in machine_list]
+      cmd.extend(names)
+      cmd.append("--zone={zone}".format(zone=self.zone))
+      self._run_command(cmd)
+
+  def _machines_from_instances(
+      self, instances: List[Dict[str, Any]]) -> List[machine.Machine]:
+    """Creates Machine Objects from json data describing created instances."""
+    machines = []
+    for instance in instances:
+      name = instance["name"]
+      kwargs = {
+          "hostname":
+              instance["networkInterfaces"][0]["accessConfigs"][0]["natIP"],
+          "key_path":
+              self.ssh_key_path,
+          "username":
+              self.ssh_user
+      }
+      machines.append(machine.RemoteMachine(name=name, **kwargs))
+    return machines
+
+  def _get_unique_names(self, num_names) -> List[str]:
+    """Returns num_names unique names based on data from the GCP project."""
+    curr_machines = self._list_machines()
+    curr_names = set([machine["name"] for machine in curr_machines])
+    ret = []
+    while len(ret) < num_names:
+      new_name = "machine-" + str(uuid.uuid4())
+      if new_name not in curr_names:
+        ret.append(new_name)
+        curr_names.update(new_name)
+    return ret
+
+  def _build_instances(self, names: List[str]) -> List[Dict[str, Any]]:
+    """Creates instances using gcloud command.
+
+    Runs the command `gcloud compute instances create` and returns json data
+    on created instances on success. Creates len(names) instances, one for each
+    name.
+
+    Args:
+      names: list of names of instances to create.
+
+    Returns:
+      List of json data describing created machines.
+    """
+    if not names:
+      raise ValueError(
+          "_build_instances cannot create instances without names.")
+    cmd = "gcloud compute instances create".split(" ")
+    cmd.extend(names)
+    cmd.extend("--preemptible --image={image} --zone={zone}".format(
+        image=self.image, zone=self.zone).split(" "))
+    if self.image_project:
+      cmd.append("--image-project={project}".format(project=self.image_project))
+      res = self._run_command(cmd)
+      return json.loads(res.stdout)
+
+  def _start_command(self, names):
+    """Starts instances using gcloud command.
+
+    Runs the command `gcloud compute instances start` on list of instances by
+    name and returns json data on started instances on success.
+
+    Args:
+      names: list of names of instances to start.
+
+    Returns:
+      List of json data describing started machines.
+    """
+    if not names:
+      raise ValueError("_start_command cannot start empty instance list.")
+    cmd = "gcloud compute instances start".split(" ")
+    cmd.extend(names)
+    cmd.append("--zone={zone}".format(zone=self.zone))
+    cmd.append("--project={project}".format(project=self.project))
+    res = self._run_command(cmd)
+    return json.loads(res.stdout)
+
+  def _add_ssh_key_to_instances(self, names: List[str]) -> None:
+    """Adds ssh key to instances by calling gcloud ssh command.
+
+    Runs the command `gcloud compute ssh instance_name` on list of images by
+    name. Tries to ssh into given instance
+
+    Args:
+      names: list of machine names to which to add the ssh-key
+        self.ssh_key_path.
+
+    Raises:
+      subprocess.CalledProcessError: when underlying subprocess call returns an
+      error other than 255 (Connection closed by remote host).
+      TimeoutError: when 3 unsuccessful tries to ssh into the host return 255.
+    """
+    for name in names:
+      cmd = "gcloud compute ssh {name}".format(name=name).split(" ")
+      cmd.append("--ssh-key-file={key}".format(key=self.ssh_key_path))
+      cmd.append("--zone={zone}".format(zone=self.zone))
+      cmd.append("--command=uname")
+      timeout = datetime.timedelta(seconds=5 * 60)
+      start = datetime.datetime.now()
+      while datetime.datetime.now() <= timeout + start:
+        try:
+          self._run_command(cmd)
+          break
+        except subprocess.CalledProcessError as e:
+          if datetime.datetime.now() > timeout + start:
+            raise TimeoutError(
+                "Could not SSH into instance after 5 min: {name}".format(
+                    name=name))
+          # 255 is the returncode for ssh connection refused.
+          elif e.returncode == 255:
+
+            continue
+          else:
+            raise e
+
+  def _list_machines(self) -> List[Dict[str, Any]]:
+    """Runs `list` gcloud command and returns list of Machine data."""
+    cmd = "gcloud compute instances list --project {project}".format(
+        project=self.project).split(" ")
+    res = self._run_command(cmd)
+    return json.loads(res.stdout)
+
+  def _run_command(self, cmd: List[str]) -> subprocess.CompletedProcess:
+    """Runs command as a subprocess.
+
+    Runs command as subprocess and returns the result.
+    If this has a mock recorder, use the record method to record the subprocess
+    call.
+
+    Args:
+      cmd: command to be run as a list of strings.
+
+    Returns:
+      Completed process object to be parsed by caller.
+
+    Raises:
+      CalledProcessError: if subprocess.run returns an error.
+    """
+    cmd = cmd + ["--format=json"]
+    res = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    if self.mock:
+      self.mock.record(res)
+    if res.returncode != 0:
+      raise subprocess.CalledProcessError(
+          cmd=res.args,
+          output=res.stdout,
+          stderr=res.stderr,
+          returncode=res.returncode)
+    return res
diff --git a/benchmarks/harness/machine_producers/gcloud_producer_test.py b/benchmarks/harness/machine_producers/gcloud_producer_test.py
new file mode 100644
index 000000000..c8adb2bdc
--- /dev/null
+++ b/benchmarks/harness/machine_producers/gcloud_producer_test.py
@@ -0,0 +1,48 @@
+# python3
+# Copyright 2019 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Tests GCloudProducer using mock data.
+
+GCloudProducer produces machines using 'get_machines' and 'release_machines'
+methods. The tests check recorded data (jsonified subprocess.CompletedProcess
+objects) of the producer producing one and five machines.
+"""
+import os
+import types
+
+from benchmarks.harness.machine_producers import machine_producer
+from benchmarks.harness.machine_producers import mock_producer
+
+TEST_DIR = os.path.dirname(__file__)
+
+
+def run_get_release(producer: machine_producer.MachineProducer,
+                    num_machines: int,
+                    validator: types.FunctionType = None):
+  machines = producer.get_machines(num_machines)
+  assert len(machines) == num_machines
+  if validator:
+    validator(machines=machines, cmd="uname -a", workload=None)
+  producer.release_machines(machines)
+
+
+def test_run_one():
+  mock = mock_producer.MockReader(TEST_DIR + "get_one.json")
+  producer = mock_producer.MockGCloudProducer(mock)
+  run_get_release(producer, 1)
+
+
+def test_run_five():
+  mock = mock_producer.MockReader(TEST_DIR + "get_five.json")
+  producer = mock_producer.MockGCloudProducer(mock)
+  run_get_release(producer, 5)
diff --git a/benchmarks/harness/machine_producers/mock_producer.py b/benchmarks/harness/machine_producers/mock_producer.py
index 4f29ad53f..37e9cb4b7 100644
--- a/benchmarks/harness/machine_producers/mock_producer.py
+++ b/benchmarks/harness/machine_producers/mock_producer.py
@@ -13,9 +13,11 @@
 # limitations under the License.
 """Producers of mocks."""
 
-from typing import List
+from typing import List, Any
 
 from benchmarks.harness import machine
+from benchmarks.harness.machine_producers import gcloud_mock_recorder
+from benchmarks.harness.machine_producers import gcloud_producer
 from benchmarks.harness.machine_producers import machine_producer
 
 
@@ -29,3 +31,22 @@ class MockMachineProducer(machine_producer.MachineProducer):
   def release_machines(self, machine_list: List[machine.MockMachine]):
     """No-op."""
     return
+
+
+class MockGCloudProducer(gcloud_producer.GCloudProducer):
+  """Mocks GCloudProducer for testing purposes."""
+
+  def __init__(self, mock: gcloud_mock_recorder.MockReader, **kwargs):
+    gcloud_producer.GCloudProducer.__init__(
+        self, project="mock", ssh_private_key_path="mock", **kwargs)
+    self.mock = mock
+
+  def _validate_ssh_file(self):
+    pass
+
+  def _run_command(self, cmd):
+    return self.mock.pop(cmd)
+
+  def _machines_from_instances(
+      self, instances: List[Any]) -> List[machine.MockMachine]:
+    return [machine.MockMachine() for _ in instances]
diff --git a/benchmarks/harness/machine_producers/testdata/get_five.json b/benchmarks/harness/machine_producers/testdata/get_five.json
new file mode 100644
index 000000000..32bad1b06
--- /dev/null
+++ b/benchmarks/harness/machine_producers/testdata/get_five.json
@@ -0,0 +1,211 @@
+[
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "instances",
+            "list",
+            "--project",
+            "project",
+            "--format=json"
+        ],
+        "stdout": "[{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]},{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]},{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]},{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]},{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":{\"natIP\":\"0.0.0.0\"}]}]}]",
+        "returncode": "0"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "instances",
+            "create",
+            "machine-42c9bf6e-8d45-4c37-b1c0-7e4fdcf530fc",
+            "machine-5f28f145-cc2d-427d-9cbf-428d164cdb92",
+            "machine-da5859b5-bae6-435d-8005-0202d6f6e065",
+            "machine-880a8a2f-918c-4f9e-a43c-ed3c8e02ea05",
+            "machine-1149147d-71e2-43ea-8fe1-49256e5c441c",
+            "--preemptible",
+            "--image=ubuntu-1910-eoan-v20191204",
+            "--zone=us-west1-b",
+            "--image-project=ubuntu-os-cloud",
+            "--format=json"
+        ],
+        "stdout": "[{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]},{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]},{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]},{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]},{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]}]",
+        "returncode": "0"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "instances",
+            "start",
+            "machine-42c9bf6e-8d45-4c37-b1c0-7e4fdcf530fc",
+            "machine-5f28f145-cc2d-427d-9cbf-428d164cdb92",
+            "machine-da5859b5-bae6-435d-8005-0202d6f6e065",
+            "machine-880a8a2f-918c-4f9e-a43c-ed3c8e02ea05",
+            "machine-1149147d-71e2-43ea-8fe1-49256e5c441c",
+            "--zone=us-west1-b",
+            "--project=project",
+            "--format=json"
+        ],
+        "stdout": "[{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]},{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]},{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]},{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]},{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]}]",
+        "returncode": "0"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "ssh",
+            "machine-42c9bf6e-8d45-4c37-b1c0-7e4fdcf530fc",
+            "--ssh-key-file=/usr/local/google/home/user/.ssh/benchmark-tools",
+            "--zone=us-west1-b",
+            "--command=uname",
+            "--format=json"
+        ],
+        "stdout": "",
+        "returncode": "255"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "ssh",
+            "machine-42c9bf6e-8d45-4c37-b1c0-7e4fdcf530fc",
+            "--ssh-key-file=/usr/local/google/home/user/.ssh/benchmark-tools",
+            "--zone=us-west1-b",
+            "--command=uname",
+            "--format=json"
+        ],
+        "stdout": "",
+        "returncode": "255"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "ssh",
+            "machine-42c9bf6e-8d45-4c37-b1c0-7e4fdcf530fc",
+            "--ssh-key-file=/usr/local/google/home/user/.ssh/benchmark-tools",
+            "--zone=us-west1-b",
+            "--command=uname",
+            "--format=json"
+        ],
+        "stdout": "",
+        "returncode": "255"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "ssh",
+            "machine-42c9bf6e-8d45-4c37-b1c0-7e4fdcf530fc",
+            "--ssh-key-file=/usr/local/google/home/user/.ssh/benchmark-tools",
+            "--zone=us-west1-b",
+            "--command=uname",
+            "--format=json"
+        ],
+        "stdout": "",
+        "returncode": "255"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "ssh",
+            "machine-42c9bf6e-8d45-4c37-b1c0-7e4fdcf530fc",
+            "--ssh-key-file=/usr/local/google/home/user/.ssh/benchmark-tools",
+            "--zone=us-west1-b",
+            "--command=uname",
+            "--format=json"
+        ],
+        "stdout": "",
+        "returncode": "255"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "ssh",
+            "machine-42c9bf6e-8d45-4c37-b1c0-7e4fdcf530fc",
+            "--ssh-key-file=/usr/local/google/home/user/.ssh/benchmark-tools",
+            "--zone=us-west1-b",
+            "--command=uname",
+            "--format=json"
+        ],
+        "stdout": "Linux\n[]\n",
+        "returncode": "0"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "ssh",
+            "machine-5f28f145-cc2d-427d-9cbf-428d164cdb92",
+            "--ssh-key-file=/usr/local/google/home/user/.ssh/benchmark-tools",
+            "--zone=us-west1-b",
+            "--command=uname",
+            "--format=json"
+        ],
+        "stdout": "Linux\n[]\n",
+        "returncode": "0"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "ssh",
+            "machine-da5859b5-bae6-435d-8005-0202d6f6e065",
+            "--ssh-key-file=/usr/local/google/home/user/.ssh/benchmark-tools",
+            "--zone=us-west1-b",
+            "--command=uname",
+            "--format=json"
+        ],
+        "stdout": "Linux\n[]\n",
+        "returncode": "0"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "ssh",
+            "machine-880a8a2f-918c-4f9e-a43c-ed3c8e02ea05",
+            "--ssh-key-file=/usr/local/google/home/user/.ssh/benchmark-tools",
+            "--zone=us-west1-b",
+            "--command=uname",
+            "--format=json"
+        ],
+        "stdout": "Linux\n[]\n",
+        "returncode": "0"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "ssh",
+            "machine-1149147d-71e2-43ea-8fe1-49256e5c441c",
+            "--ssh-key-file=/usr/local/google/home/user/.ssh/benchmark-tools",
+            "--zone=us-west1-b",
+            "--command=uname",
+            "--format=json"
+        ],
+        "stdout": "Linux\n[]\n",
+        "returncode": "0"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "instances",
+            "delete",
+            "--quiet",
+            "machine-42c9bf6e-8d45-4c37-b1c0-7e4fdcf530fc",
+            "machine-5f28f145-cc2d-427d-9cbf-428d164cdb92",
+            "machine-da5859b5-bae6-435d-8005-0202d6f6e065",
+            "machine-880a8a2f-918c-4f9e-a43c-ed3c8e02ea05",
+            "machine-1149147d-71e2-43ea-8fe1-49256e5c441c",
+            "--zone=us-west1-b",
+            "--format=json"
+        ],
+        "stdout": "[]\n",
+        "returncode": "0"
+    }
+]
diff --git a/benchmarks/harness/machine_producers/testdata/get_one.json b/benchmarks/harness/machine_producers/testdata/get_one.json
new file mode 100644
index 000000000..c359c19c8
--- /dev/null
+++ b/benchmarks/harness/machine_producers/testdata/get_one.json
@@ -0,0 +1,145 @@
+[
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "instances",
+            "list",
+            "--project",
+            "linux-testing-user",
+            "--format=json"
+        ],
+        "stdout": "[{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]}]",
+
+        "returncode": "0"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "instances",
+            "create",
+            "machine-129dfcf9-b05b-4c16-a4cd-21353b570ddc",
+            "--preemptible",
+            "--image=ubuntu-1910-eoan-v20191204",
+            "--zone=us-west1-b",
+            "--image-project=ubuntu-os-cloud",
+            "--format=json"
+        ],
+        "stdout": "[{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]}]",
+        "returncode": "0"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "instances",
+            "start",
+            "machine-129dfcf9-b05b-4c16-a4cd-21353b570ddc",
+            "--zone=us-west1-b",
+            "--project=linux-testing-user",
+            "--format=json"
+        ],
+        "stdout": "[{\"name\":\"name\", \"networkInterfaces\":[{\"accessConfigs\":[{\"natIP\":\"0.0.0.0\"}]}]}]",
+        
+        "returncode": "0"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "ssh",
+            "machine-129dfcf9-b05b-4c16-a4cd-21353b570ddc",
+            "--ssh-key-file=/usr/local/google/home/user/.ssh/benchmark-tools",
+            "--zone=us-west1-b",
+            "--command=uname",
+            "--format=json"
+        ],
+        "stdout": "",
+        "returncode": "255"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "ssh",
+            "machine-129dfcf9-b05b-4c16-a4cd-21353b570ddc",
+            "--ssh-key-file=/usr/local/google/home/user/.ssh/benchmark-tools",
+            "--zone=us-west1-b",
+            "--command=uname",
+            "--format=json"
+        ],
+        "stdout": "",
+        "returncode": "255"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "ssh",
+            "machine-129dfcf9-b05b-4c16-a4cd-21353b570ddc",
+            "--ssh-key-file=/usr/local/google/home/user/.ssh/benchmark-tools",
+            "--zone=us-west1-b",
+            "--command=uname",
+            "--format=json"
+        ],
+        "stdout": "",
+        "returncode": "255"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "ssh",
+            "machine-129dfcf9-b05b-4c16-a4cd-21353b570ddc",
+            "--ssh-key-file=/usr/local/google/home/user/.ssh/benchmark-tools",
+            "--zone=us-west1-b",
+            "--command=uname",
+            "--format=json"
+        ],
+        "stdout": "",
+        "returncode": "255"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "ssh",
+            "machine-129dfcf9-b05b-4c16-a4cd-21353b570ddc",
+            "--ssh-key-file=/usr/local/google/home/user/.ssh/benchmark-tools",
+            "--zone=us-west1-b",
+            "--command=uname",
+            "--format=json"
+        ],
+        "stdout": "",
+        "returncode": "255"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "ssh",
+            "machine-129dfcf9-b05b-4c16-a4cd-21353b570ddc",
+            "--ssh-key-file=/usr/local/google/home/user/.ssh/benchmark-tools",
+            "--zone=us-west1-b",
+            "--command=uname",
+            "--format=json"
+        ],
+        "stdout": "Linux\n[]\n",
+        "returncode": "0"
+    },
+    {
+        "args": [
+            "gcloud",
+            "compute",
+            "instances",
+            "delete",
+            "--quiet",
+            "machine-129dfcf9-b05b-4c16-a4cd-21353b570ddc",
+            "--zone=us-west1-b",
+            "--format=json"
+        ],
+        "stdout": "[]\n",
+        "returncode": "0"
+    }
+]
-- 
cgit v1.2.3


From 356d81146bafc4b4548163eb87e886c851b49e12 Mon Sep 17 00:00:00 2001
From: Bhasker Hariharan <bhaskerh@google.com>
Date: Thu, 9 Jan 2020 17:56:58 -0800
Subject: Deflake a couple of TCP syscall tests when run under gotsan.

PiperOrigin-RevId: 289010316
---
 .../linux/socket_bind_to_device_distribution.cc    | 25 ++++++++++++++++++--
 test/syscalls/linux/socket_inet_loopback.cc        | 27 +++++++++++++++++++---
 2 files changed, 47 insertions(+), 5 deletions(-)

diff --git a/test/syscalls/linux/socket_bind_to_device_distribution.cc b/test/syscalls/linux/socket_bind_to_device_distribution.cc
index 5767181a1..5ed57625c 100644
--- a/test/syscalls/linux/socket_bind_to_device_distribution.cc
+++ b/test/syscalls/linux/socket_bind_to_device_distribution.cc
@@ -183,7 +183,14 @@ TEST_P(BindToDeviceDistributionTest, Tcp) {
             }
             // Receive some data from a socket to be sure that the connect()
             // system call has been completed on another side.
-            int data;
+            // Do a short read and then close the socket to trigger a RST. This
+            // ensures that both ends of the connection are cleaned up and no
+            // goroutines hang around in TIME-WAIT. We do this so that this test
+            // does not timeout under gotsan runs where lots of goroutines can
+            // cause the test to use absurd amounts of memory.
+            //
+            // See: https://tools.ietf.org/html/rfc2525#page-50 section 2.17
+            uint16_t data;
             EXPECT_THAT(
                 RetryEINTR(recv)(fd.ValueOrDie().get(), &data, sizeof(data), 0),
                 SyscallSucceedsWithValue(sizeof(data)));
@@ -198,15 +205,29 @@ TEST_P(BindToDeviceDistributionTest, Tcp) {
   }
 
   for (int i = 0; i < kConnectAttempts; i++) {
-    FileDescriptor const fd = ASSERT_NO_ERRNO_AND_VALUE(
+    const FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(
         Socket(connector.family(), SOCK_STREAM, IPPROTO_TCP));
     ASSERT_THAT(
         RetryEINTR(connect)(fd.get(), reinterpret_cast<sockaddr*>(&conn_addr),
                             connector.addr_len),
         SyscallSucceeds());
 
+    // Do two separate sends to ensure two segments are received. This is
+    // required for netstack where read is incorrectly assuming a whole
+    // segment is read when endpoint.Read() is called which is technically
+    // incorrect as the syscall that invoked endpoint.Read() may only
+    // consume it partially. This results in a case where a close() of
+    // such a socket does not trigger a RST in netstack due to the
+    // endpoint assuming that the endpoint has no unread data.
     EXPECT_THAT(RetryEINTR(send)(fd.get(), &i, sizeof(i), 0),
                 SyscallSucceedsWithValue(sizeof(i)));
+
+    // TODO(gvisor.dev/issue/1449): Remove this block once netstack correctly
+    //   generates a RST.
+    if (IsRunningOnGvisor()) {
+      EXPECT_THAT(RetryEINTR(send)(fd.get(), &i, sizeof(i), 0),
+                  SyscallSucceedsWithValue(sizeof(i)));
+    }
   }
 
   // Join threads to be sure that all connections have been counted.
diff --git a/test/syscalls/linux/socket_inet_loopback.cc b/test/syscalls/linux/socket_inet_loopback.cc
index 619d41901..138024d9e 100644
--- a/test/syscalls/linux/socket_inet_loopback.cc
+++ b/test/syscalls/linux/socket_inet_loopback.cc
@@ -714,7 +714,7 @@ TEST_P(SocketInetReusePortTest, TcpPortReuseMultiThread_NoRandomSave) {
   sockaddr_storage listen_addr = listener.addr;
   sockaddr_storage conn_addr = connector.addr;
   constexpr int kThreadCount = 3;
-  constexpr int kConnectAttempts = 4096;
+  constexpr int kConnectAttempts = 10000;
 
   // Create the listening socket.
   FileDescriptor listener_fds[kThreadCount];
@@ -729,7 +729,7 @@ TEST_P(SocketInetReusePortTest, TcpPortReuseMultiThread_NoRandomSave) {
     ASSERT_THAT(
         bind(fd, reinterpret_cast<sockaddr*>(&listen_addr), listener.addr_len),
         SyscallSucceeds());
-    ASSERT_THAT(listen(fd, kConnectAttempts / 3), SyscallSucceeds());
+    ASSERT_THAT(listen(fd, 40), SyscallSucceeds());
 
     // On the first bind we need to determine which port was bound.
     if (i != 0) {
@@ -772,7 +772,14 @@ TEST_P(SocketInetReusePortTest, TcpPortReuseMultiThread_NoRandomSave) {
             }
             // Receive some data from a socket to be sure that the connect()
             // system call has been completed on another side.
-            int data;
+            // Do a short read and then close the socket to trigger a RST. This
+            // ensures that both ends of the connection are cleaned up and no
+            // goroutines hang around in TIME-WAIT. We do this so that this test
+            // does not timeout under gotsan runs where lots of goroutines can
+            // cause the test to use absurd amounts of memory.
+            //
+            // See: https://tools.ietf.org/html/rfc2525#page-50 section 2.17
+            uint16_t data;
             EXPECT_THAT(
                 RetryEINTR(recv)(fd.ValueOrDie().get(), &data, sizeof(data), 0),
                 SyscallSucceedsWithValue(sizeof(data)));
@@ -795,8 +802,22 @@ TEST_P(SocketInetReusePortTest, TcpPortReuseMultiThread_NoRandomSave) {
                               connector.addr_len),
           SyscallSucceeds());
 
+      // Do two separate sends to ensure two segments are received. This is
+      // required for netstack where read is incorrectly assuming a whole
+      // segment is read when endpoint.Read() is called which is technically
+      // incorrect as the syscall that invoked endpoint.Read() may only
+      // consume it partially. This results in a case where a close() of
+      // such a socket does not trigger a RST in netstack due to the
+      // endpoint assuming that the endpoint has no unread data.
       EXPECT_THAT(RetryEINTR(send)(fd.get(), &i, sizeof(i), 0),
                   SyscallSucceedsWithValue(sizeof(i)));
+
+      // TODO(gvisor.dev/issue/1449): Remove this block once netstack correctly
+      //   generates a RST.
+      if (IsRunningOnGvisor()) {
+        EXPECT_THAT(RetryEINTR(send)(fd.get(), &i, sizeof(i), 0),
+                    SyscallSucceedsWithValue(sizeof(i)));
+      }
     }
   });
 
-- 
cgit v1.2.3


From 27500d529f7fb87eef8812278fd1bbca67bcba72 Mon Sep 17 00:00:00 2001
From: Ian Gudger <igudger@google.com>
Date: Thu, 9 Jan 2020 22:00:42 -0800
Subject: New sync package.

* Rename syncutil to sync.
* Add aliases to sync types.
* Replace existing usage of standard library sync package.

This will make it easier to swap out synchronization primitives. For example,
this will allow us to use primitives from github.com/sasha-s/go-deadlock to
check for lock ordering violations.

Updates #1472

PiperOrigin-RevId: 289033387
---
 pkg/amutex/BUILD                                   |   1 +
 pkg/amutex/amutex_test.go                          |   3 +-
 pkg/atomicbitops/BUILD                             |   1 +
 pkg/atomicbitops/atomic_bitops_test.go             |   3 +-
 pkg/compressio/BUILD                               |   5 +-
 pkg/compressio/compressio.go                       |   2 +-
 pkg/control/server/BUILD                           |   1 +
 pkg/control/server/server.go                       |   2 +-
 pkg/eventchannel/BUILD                             |   2 +
 pkg/eventchannel/event.go                          |   2 +-
 pkg/eventchannel/event_test.go                     |   2 +-
 pkg/fdchannel/BUILD                                |   1 +
 pkg/fdchannel/fdchannel_test.go                    |   3 +-
 pkg/fdnotifier/BUILD                               |   1 +
 pkg/fdnotifier/fdnotifier.go                       |   2 +-
 pkg/flipcall/BUILD                                 |   3 +-
 pkg/flipcall/flipcall_example_test.go              |   3 +-
 pkg/flipcall/flipcall_test.go                      |   3 +-
 pkg/flipcall/flipcall_unsafe.go                    |  10 +-
 pkg/gate/BUILD                                     |   1 +
 pkg/gate/gate_test.go                              |   2 +-
 pkg/linewriter/BUILD                               |   1 +
 pkg/linewriter/linewriter.go                       |   3 +-
 pkg/log/BUILD                                      |   5 +-
 pkg/log/log.go                                     |   2 +-
 pkg/metric/BUILD                                   |   1 +
 pkg/metric/metric.go                               |   2 +-
 pkg/p9/BUILD                                       |   1 +
 pkg/p9/client.go                                   |   2 +-
 pkg/p9/p9test/BUILD                                |   2 +
 pkg/p9/p9test/client_test.go                       |   2 +-
 pkg/p9/p9test/p9test.go                            |   2 +-
 pkg/p9/path_tree.go                                |   3 +-
 pkg/p9/pool.go                                     |   2 +-
 pkg/p9/server.go                                   |   2 +-
 pkg/p9/transport.go                                |   2 +-
 pkg/procid/BUILD                                   |   2 +
 pkg/procid/procid_test.go                          |   3 +-
 pkg/rand/BUILD                                     |   5 +-
 pkg/rand/rand_linux.go                             |   2 +-
 pkg/refs/BUILD                                     |   2 +
 pkg/refs/refcounter.go                             |   2 +-
 pkg/refs/refcounter_test.go                        |   3 +-
 pkg/sentry/arch/BUILD                              |   1 +
 pkg/sentry/arch/arch_x86.go                        |   2 +-
 pkg/sentry/control/BUILD                           |   1 +
 pkg/sentry/control/pprof.go                        |   2 +-
 pkg/sentry/device/BUILD                            |   5 +-
 pkg/sentry/device/device.go                        |   2 +-
 pkg/sentry/fs/BUILD                                |   3 +-
 pkg/sentry/fs/copy_up.go                           |   2 +-
 pkg/sentry/fs/copy_up_test.go                      |   2 +-
 pkg/sentry/fs/dirent.go                            |   2 +-
 pkg/sentry/fs/dirent_cache.go                      |   3 +-
 pkg/sentry/fs/dirent_cache_limiter.go              |   3 +-
 pkg/sentry/fs/fdpipe/BUILD                         |   1 +
 pkg/sentry/fs/fdpipe/pipe.go                       |   2 +-
 pkg/sentry/fs/fdpipe/pipe_state.go                 |   2 +-
 pkg/sentry/fs/file.go                              |   2 +-
 pkg/sentry/fs/file_overlay.go                      |   2 +-
 pkg/sentry/fs/filesystems.go                       |   2 +-
 pkg/sentry/fs/fs.go                                |   3 +-
 pkg/sentry/fs/fsutil/BUILD                         |   1 +
 pkg/sentry/fs/fsutil/host_file_mapper.go           |   2 +-
 pkg/sentry/fs/fsutil/host_mappable.go              |   2 +-
 pkg/sentry/fs/fsutil/inode.go                      |   3 +-
 pkg/sentry/fs/fsutil/inode_cached.go               |   2 +-
 pkg/sentry/fs/gofer/BUILD                          |   1 +
 pkg/sentry/fs/gofer/inode.go                       |   2 +-
 pkg/sentry/fs/gofer/session.go                     |   2 +-
 pkg/sentry/fs/host/BUILD                           |   1 +
 pkg/sentry/fs/host/inode.go                        |   2 +-
 pkg/sentry/fs/host/socket.go                       |   2 +-
 pkg/sentry/fs/host/tty.go                          |   3 +-
 pkg/sentry/fs/inode.go                             |   3 +-
 pkg/sentry/fs/inode_inotify.go                     |   3 +-
 pkg/sentry/fs/inotify.go                           |   2 +-
 pkg/sentry/fs/inotify_watch.go                     |   2 +-
 pkg/sentry/fs/lock/BUILD                           |   1 +
 pkg/sentry/fs/lock/lock.go                         |   2 +-
 pkg/sentry/fs/mounts.go                            |   2 +-
 pkg/sentry/fs/overlay.go                           |   5 +-
 pkg/sentry/fs/proc/BUILD                           |   1 +
 pkg/sentry/fs/proc/seqfile/BUILD                   |   1 +
 pkg/sentry/fs/proc/seqfile/seqfile.go              |   2 +-
 pkg/sentry/fs/proc/sys_net.go                      |   2 +-
 pkg/sentry/fs/ramfs/BUILD                          |   1 +
 pkg/sentry/fs/ramfs/dir.go                         |   2 +-
 pkg/sentry/fs/restore.go                           |   2 +-
 pkg/sentry/fs/tmpfs/BUILD                          |   1 +
 pkg/sentry/fs/tmpfs/inode_file.go                  |   2 +-
 pkg/sentry/fs/tty/BUILD                            |   1 +
 pkg/sentry/fs/tty/dir.go                           |   2 +-
 pkg/sentry/fs/tty/line_discipline.go               |   2 +-
 pkg/sentry/fs/tty/queue.go                         |   3 +-
 pkg/sentry/fsimpl/ext/BUILD                        |   1 +
 pkg/sentry/fsimpl/ext/directory.go                 |   3 +-
 pkg/sentry/fsimpl/ext/filesystem.go                |   2 +-
 pkg/sentry/fsimpl/ext/regular_file.go              |   2 +-
 pkg/sentry/fsimpl/kernfs/BUILD                     |   2 +
 pkg/sentry/fsimpl/kernfs/inode_impl_util.go        |   2 +-
 pkg/sentry/fsimpl/kernfs/kernfs.go                 |   2 +-
 pkg/sentry/fsimpl/kernfs/kernfs_test.go            |   2 +-
 pkg/sentry/fsimpl/tmpfs/BUILD                      |   1 +
 pkg/sentry/fsimpl/tmpfs/regular_file.go            |   2 +-
 pkg/sentry/fsimpl/tmpfs/tmpfs.go                   |   2 +-
 pkg/sentry/kernel/BUILD                            |   5 +-
 pkg/sentry/kernel/abstract_socket_namespace.go     |   2 +-
 pkg/sentry/kernel/auth/BUILD                       |   3 +-
 pkg/sentry/kernel/auth/user_namespace.go           |   2 +-
 pkg/sentry/kernel/epoll/BUILD                      |   1 +
 pkg/sentry/kernel/epoll/epoll.go                   |   2 +-
 pkg/sentry/kernel/eventfd/BUILD                    |   1 +
 pkg/sentry/kernel/eventfd/eventfd.go               |   2 +-
 pkg/sentry/kernel/fasync/BUILD                     |   1 +
 pkg/sentry/kernel/fasync/fasync.go                 |   3 +-
 pkg/sentry/kernel/fd_table.go                      |   2 +-
 pkg/sentry/kernel/fd_table_test.go                 |   2 +-
 pkg/sentry/kernel/fs_context.go                    |   2 +-
 pkg/sentry/kernel/futex/BUILD                      |   8 +-
 pkg/sentry/kernel/futex/futex.go                   |   3 +-
 pkg/sentry/kernel/futex/futex_test.go              |   2 +-
 pkg/sentry/kernel/kernel.go                        |   2 +-
 pkg/sentry/kernel/memevent/BUILD                   |   1 +
 pkg/sentry/kernel/memevent/memory_events.go        |   2 +-
 pkg/sentry/kernel/pipe/BUILD                       |   1 +
 pkg/sentry/kernel/pipe/buffer.go                   |   2 +-
 pkg/sentry/kernel/pipe/node.go                     |   3 +-
 pkg/sentry/kernel/pipe/pipe.go                     |   2 +-
 pkg/sentry/kernel/pipe/pipe_util.go                |   2 +-
 pkg/sentry/kernel/pipe/vfs.go                      |   3 +-
 pkg/sentry/kernel/semaphore/BUILD                  |   1 +
 pkg/sentry/kernel/semaphore/semaphore.go           |   2 +-
 pkg/sentry/kernel/shm/BUILD                        |   1 +
 pkg/sentry/kernel/shm/shm.go                       |   2 +-
 pkg/sentry/kernel/signal_handlers.go               |   3 +-
 pkg/sentry/kernel/signalfd/BUILD                   |   1 +
 pkg/sentry/kernel/signalfd/signalfd.go             |   3 +-
 pkg/sentry/kernel/syscalls.go                      |   2 +-
 pkg/sentry/kernel/syslog.go                        |   3 +-
 pkg/sentry/kernel/task.go                          |   5 +-
 pkg/sentry/kernel/thread_group.go                  |   2 +-
 pkg/sentry/kernel/threads.go                       |   2 +-
 pkg/sentry/kernel/time/BUILD                       |   1 +
 pkg/sentry/kernel/time/time.go                     |   2 +-
 pkg/sentry/kernel/timekeeper.go                    |   2 +-
 pkg/sentry/kernel/tty.go                           |   2 +-
 pkg/sentry/kernel/uts_namespace.go                 |   3 +-
 pkg/sentry/limits/BUILD                            |   1 +
 pkg/sentry/limits/limits.go                        |   3 +-
 pkg/sentry/mm/BUILD                                |   2 +-
 pkg/sentry/mm/aio_context.go                       |   3 +-
 pkg/sentry/mm/mm.go                                |   8 +-
 pkg/sentry/pgalloc/BUILD                           |   1 +
 pkg/sentry/pgalloc/pgalloc.go                      |   2 +-
 pkg/sentry/platform/interrupt/BUILD                |   1 +
 pkg/sentry/platform/interrupt/interrupt.go         |   3 +-
 pkg/sentry/platform/kvm/BUILD                      |   1 +
 pkg/sentry/platform/kvm/address_space.go           |   2 +-
 pkg/sentry/platform/kvm/bluepill_arm64_unsafe.go   |   2 -
 pkg/sentry/platform/kvm/kvm.go                     |   2 +-
 pkg/sentry/platform/kvm/machine.go                 |   2 +-
 pkg/sentry/platform/ptrace/BUILD                   |   1 +
 pkg/sentry/platform/ptrace/ptrace.go               |   2 +-
 pkg/sentry/platform/ptrace/subprocess.go           |   2 +-
 .../platform/ptrace/subprocess_linux_unsafe.go     |   2 +-
 pkg/sentry/platform/ring0/defs.go                  |   2 +-
 pkg/sentry/platform/ring0/defs_amd64.go            |   1 +
 pkg/sentry/platform/ring0/defs_arm64.go            |   1 +
 pkg/sentry/platform/ring0/pagetables/BUILD         |   5 +-
 pkg/sentry/platform/ring0/pagetables/pcids_x86.go  |   2 +-
 pkg/sentry/socket/netlink/BUILD                    |   1 +
 pkg/sentry/socket/netlink/port/BUILD               |   1 +
 pkg/sentry/socket/netlink/port/port.go             |   3 +-
 pkg/sentry/socket/netlink/socket.go                |   2 +-
 pkg/sentry/socket/netstack/BUILD                   |   1 +
 pkg/sentry/socket/netstack/netstack.go             |   2 +-
 pkg/sentry/socket/rpcinet/conn/BUILD               |   1 +
 pkg/sentry/socket/rpcinet/conn/conn.go             |   2 +-
 pkg/sentry/socket/rpcinet/notifier/BUILD           |   1 +
 pkg/sentry/socket/rpcinet/notifier/notifier.go     |   2 +-
 pkg/sentry/socket/unix/transport/BUILD             |   1 +
 pkg/sentry/socket/unix/transport/connectioned.go   |   3 +-
 pkg/sentry/socket/unix/transport/queue.go          |   3 +-
 pkg/sentry/socket/unix/transport/unix.go           |   2 +-
 pkg/sentry/syscalls/linux/BUILD                    |   1 +
 pkg/sentry/syscalls/linux/error.go                 |   2 +-
 pkg/sentry/time/BUILD                              |   4 +-
 pkg/sentry/time/calibrated_clock.go                |   2 +-
 pkg/sentry/usage/BUILD                             |   1 +
 pkg/sentry/usage/memory.go                         |   2 +-
 pkg/sentry/vfs/BUILD                               |   3 +-
 pkg/sentry/vfs/dentry.go                           |   2 +-
 pkg/sentry/vfs/file_description_impl_util.go       |   2 +-
 pkg/sentry/vfs/mount_test.go                       |   3 +-
 pkg/sentry/vfs/mount_unsafe.go                     |   4 +-
 pkg/sentry/vfs/pathname.go                         |   3 +-
 pkg/sentry/vfs/resolving_path.go                   |   2 +-
 pkg/sentry/vfs/vfs.go                              |   2 +-
 pkg/sentry/watchdog/BUILD                          |   1 +
 pkg/sentry/watchdog/watchdog.go                    |   2 +-
 pkg/sync/BUILD                                     |  53 +++++++
 pkg/sync/LICENSE                                   |  27 ++++
 pkg/sync/README.md                                 |   5 +
 pkg/sync/aliases.go                                |  37 +++++
 pkg/sync/atomicptr_unsafe.go                       |  47 +++++++
 pkg/sync/atomicptrtest/BUILD                       |  29 ++++
 pkg/sync/atomicptrtest/atomicptr_test.go           |  31 +++++
 pkg/sync/downgradable_rwmutex_test.go              | 150 ++++++++++++++++++++
 pkg/sync/downgradable_rwmutex_unsafe.go            | 146 ++++++++++++++++++++
 pkg/sync/memmove_unsafe.go                         |  28 ++++
 pkg/sync/norace_unsafe.go                          |  35 +++++
 pkg/sync/race_unsafe.go                            |  41 ++++++
 pkg/sync/seqatomic_unsafe.go                       |  72 ++++++++++
 pkg/sync/seqatomictest/BUILD                       |  33 +++++
 pkg/sync/seqatomictest/seqatomic_test.go           | 132 ++++++++++++++++++
 pkg/sync/seqcount.go                               | 149 ++++++++++++++++++++
 pkg/sync/seqcount_test.go                          | 153 +++++++++++++++++++++
 pkg/sync/syncutil.go                               |   7 +
 pkg/syncutil/BUILD                                 |  52 -------
 pkg/syncutil/LICENSE                               |  27 ----
 pkg/syncutil/README.md                             |   5 -
 pkg/syncutil/atomicptr_unsafe.go                   |  47 -------
 pkg/syncutil/atomicptrtest/BUILD                   |  29 ----
 pkg/syncutil/atomicptrtest/atomicptr_test.go       |  31 -----
 pkg/syncutil/downgradable_rwmutex_test.go          | 150 --------------------
 pkg/syncutil/downgradable_rwmutex_unsafe.go        | 146 --------------------
 pkg/syncutil/memmove_unsafe.go                     |  28 ----
 pkg/syncutil/norace_unsafe.go                      |  35 -----
 pkg/syncutil/race_unsafe.go                        |  41 ------
 pkg/syncutil/seqatomic_unsafe.go                   |  72 ----------
 pkg/syncutil/seqatomictest/BUILD                   |  35 -----
 pkg/syncutil/seqatomictest/seqatomic_test.go       | 132 ------------------
 pkg/syncutil/seqcount.go                           | 149 --------------------
 pkg/syncutil/seqcount_test.go                      | 153 ---------------------
 pkg/syncutil/syncutil.go                           |   7 -
 pkg/tcpip/BUILD                                    |   1 +
 pkg/tcpip/adapters/gonet/BUILD                     |   1 +
 pkg/tcpip/adapters/gonet/gonet.go                  |   2 +-
 pkg/tcpip/link/fdbased/BUILD                       |   1 +
 pkg/tcpip/link/fdbased/endpoint.go                 |   2 +-
 pkg/tcpip/link/sharedmem/BUILD                     |   2 +
 pkg/tcpip/link/sharedmem/pipe/BUILD                |   1 +
 pkg/tcpip/link/sharedmem/pipe/pipe_test.go         |   3 +-
 pkg/tcpip/link/sharedmem/sharedmem.go              |   2 +-
 pkg/tcpip/link/sharedmem/sharedmem_test.go         |   2 +-
 pkg/tcpip/network/fragmentation/BUILD              |   1 +
 pkg/tcpip/network/fragmentation/fragmentation.go   |   2 +-
 pkg/tcpip/network/fragmentation/reassembler.go     |   2 +-
 pkg/tcpip/ports/BUILD                              |   1 +
 pkg/tcpip/ports/ports.go                           |   2 +-
 pkg/tcpip/stack/BUILD                              |   2 +
 pkg/tcpip/stack/linkaddrcache.go                   |   2 +-
 pkg/tcpip/stack/linkaddrcache_test.go              |   2 +-
 pkg/tcpip/stack/nic.go                             |   2 +-
 pkg/tcpip/stack/stack.go                           |   2 +-
 pkg/tcpip/stack/transport_demuxer.go               |   2 +-
 pkg/tcpip/tcpip.go                                 |   2 +-
 pkg/tcpip/transport/icmp/BUILD                     |   1 +
 pkg/tcpip/transport/icmp/endpoint.go               |   3 +-
 pkg/tcpip/transport/packet/BUILD                   |   1 +
 pkg/tcpip/transport/packet/endpoint.go             |   3 +-
 pkg/tcpip/transport/raw/BUILD                      |   1 +
 pkg/tcpip/transport/raw/endpoint.go                |   3 +-
 pkg/tcpip/transport/tcp/BUILD                      |   1 +
 pkg/tcpip/transport/tcp/accept.go                  |   2 +-
 pkg/tcpip/transport/tcp/connect.go                 |   2 +-
 pkg/tcpip/transport/tcp/endpoint.go                |   2 +-
 pkg/tcpip/transport/tcp/endpoint_state.go          |   2 +-
 pkg/tcpip/transport/tcp/forwarder.go               |   3 +-
 pkg/tcpip/transport/tcp/protocol.go                |   2 +-
 pkg/tcpip/transport/tcp/segment_queue.go           |   2 +-
 pkg/tcpip/transport/tcp/snd.go                     |   2 +-
 pkg/tcpip/transport/udp/BUILD                      |   1 +
 pkg/tcpip/transport/udp/endpoint.go                |   3 +-
 pkg/tmutex/BUILD                                   |   1 +
 pkg/tmutex/tmutex_test.go                          |   3 +-
 pkg/unet/BUILD                                     |   1 +
 pkg/unet/unet_test.go                              |   3 +-
 pkg/urpc/BUILD                                     |   1 +
 pkg/urpc/urpc.go                                   |   2 +-
 pkg/waiter/BUILD                                   |   1 +
 pkg/waiter/waiter.go                               |   2 +-
 runsc/boot/BUILD                                   |   2 +
 runsc/boot/compat.go                               |   2 +-
 runsc/boot/limits.go                               |   2 +-
 runsc/boot/loader.go                               |   2 +-
 runsc/boot/loader_test.go                          |   2 +-
 runsc/cmd/BUILD                                    |   1 +
 runsc/cmd/create.go                                |   1 +
 runsc/cmd/gofer.go                                 |   2 +-
 runsc/cmd/start.go                                 |   1 +
 runsc/container/BUILD                              |   2 +
 runsc/container/console_test.go                    |   2 +-
 runsc/container/container_test.go                  |   2 +-
 runsc/container/multi_container_test.go            |   2 +-
 runsc/container/state_file.go                      |   2 +-
 runsc/fsgofer/BUILD                                |   1 +
 runsc/fsgofer/fsgofer.go                           |   2 +-
 runsc/sandbox/BUILD                                |   1 +
 runsc/sandbox/sandbox.go                           |   2 +-
 runsc/testutil/BUILD                               |   1 +
 runsc/testutil/testutil.go                         |   2 +-
 303 files changed, 1507 insertions(+), 1368 deletions(-)
 create mode 100644 pkg/sync/BUILD
 create mode 100644 pkg/sync/LICENSE
 create mode 100644 pkg/sync/README.md
 create mode 100644 pkg/sync/aliases.go
 create mode 100644 pkg/sync/atomicptr_unsafe.go
 create mode 100644 pkg/sync/atomicptrtest/BUILD
 create mode 100644 pkg/sync/atomicptrtest/atomicptr_test.go
 create mode 100644 pkg/sync/downgradable_rwmutex_test.go
 create mode 100644 pkg/sync/downgradable_rwmutex_unsafe.go
 create mode 100644 pkg/sync/memmove_unsafe.go
 create mode 100644 pkg/sync/norace_unsafe.go
 create mode 100644 pkg/sync/race_unsafe.go
 create mode 100644 pkg/sync/seqatomic_unsafe.go
 create mode 100644 pkg/sync/seqatomictest/BUILD
 create mode 100644 pkg/sync/seqatomictest/seqatomic_test.go
 create mode 100644 pkg/sync/seqcount.go
 create mode 100644 pkg/sync/seqcount_test.go
 create mode 100644 pkg/sync/syncutil.go
 delete mode 100644 pkg/syncutil/BUILD
 delete mode 100644 pkg/syncutil/LICENSE
 delete mode 100644 pkg/syncutil/README.md
 delete mode 100644 pkg/syncutil/atomicptr_unsafe.go
 delete mode 100644 pkg/syncutil/atomicptrtest/BUILD
 delete mode 100644 pkg/syncutil/atomicptrtest/atomicptr_test.go
 delete mode 100644 pkg/syncutil/downgradable_rwmutex_test.go
 delete mode 100644 pkg/syncutil/downgradable_rwmutex_unsafe.go
 delete mode 100644 pkg/syncutil/memmove_unsafe.go
 delete mode 100644 pkg/syncutil/norace_unsafe.go
 delete mode 100644 pkg/syncutil/race_unsafe.go
 delete mode 100644 pkg/syncutil/seqatomic_unsafe.go
 delete mode 100644 pkg/syncutil/seqatomictest/BUILD
 delete mode 100644 pkg/syncutil/seqatomictest/seqatomic_test.go
 delete mode 100644 pkg/syncutil/seqcount.go
 delete mode 100644 pkg/syncutil/seqcount_test.go
 delete mode 100644 pkg/syncutil/syncutil.go

diff --git a/pkg/amutex/BUILD b/pkg/amutex/BUILD
index 6bc486b62..d99e37b40 100644
--- a/pkg/amutex/BUILD
+++ b/pkg/amutex/BUILD
@@ -15,4 +15,5 @@ go_test(
     size = "small",
     srcs = ["amutex_test.go"],
     embed = [":amutex"],
+    deps = ["//pkg/sync"],
 )
diff --git a/pkg/amutex/amutex_test.go b/pkg/amutex/amutex_test.go
index 1d7f45641..8a3952f2a 100644
--- a/pkg/amutex/amutex_test.go
+++ b/pkg/amutex/amutex_test.go
@@ -15,9 +15,10 @@
 package amutex
 
 import (
-	"sync"
 	"testing"
 	"time"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 type sleeper struct {
diff --git a/pkg/atomicbitops/BUILD b/pkg/atomicbitops/BUILD
index 36beaade9..6403c60c2 100644
--- a/pkg/atomicbitops/BUILD
+++ b/pkg/atomicbitops/BUILD
@@ -20,4 +20,5 @@ go_test(
     size = "small",
     srcs = ["atomic_bitops_test.go"],
     embed = [":atomicbitops"],
+    deps = ["//pkg/sync"],
 )
diff --git a/pkg/atomicbitops/atomic_bitops_test.go b/pkg/atomicbitops/atomic_bitops_test.go
index 965e9be79..9466d3e23 100644
--- a/pkg/atomicbitops/atomic_bitops_test.go
+++ b/pkg/atomicbitops/atomic_bitops_test.go
@@ -16,8 +16,9 @@ package atomicbitops
 
 import (
 	"runtime"
-	"sync"
 	"testing"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 const iterations = 100
diff --git a/pkg/compressio/BUILD b/pkg/compressio/BUILD
index a0b21d4bd..2bb581b18 100644
--- a/pkg/compressio/BUILD
+++ b/pkg/compressio/BUILD
@@ -8,7 +8,10 @@ go_library(
     srcs = ["compressio.go"],
     importpath = "gvisor.dev/gvisor/pkg/compressio",
     visibility = ["//:sandbox"],
-    deps = ["//pkg/binary"],
+    deps = [
+        "//pkg/binary",
+        "//pkg/sync",
+    ],
 )
 
 go_test(
diff --git a/pkg/compressio/compressio.go b/pkg/compressio/compressio.go
index 3b0bb086e..5f52cbe74 100644
--- a/pkg/compressio/compressio.go
+++ b/pkg/compressio/compressio.go
@@ -52,9 +52,9 @@ import (
 	"hash"
 	"io"
 	"runtime"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/binary"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 var bufPool = sync.Pool{
diff --git a/pkg/control/server/BUILD b/pkg/control/server/BUILD
index 21adf3adf..adbd1e3f8 100644
--- a/pkg/control/server/BUILD
+++ b/pkg/control/server/BUILD
@@ -9,6 +9,7 @@ go_library(
     visibility = ["//:sandbox"],
     deps = [
         "//pkg/log",
+        "//pkg/sync",
         "//pkg/unet",
         "//pkg/urpc",
     ],
diff --git a/pkg/control/server/server.go b/pkg/control/server/server.go
index a56152d10..41abe1f2d 100644
--- a/pkg/control/server/server.go
+++ b/pkg/control/server/server.go
@@ -22,9 +22,9 @@ package server
 
 import (
 	"os"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/unet"
 	"gvisor.dev/gvisor/pkg/urpc"
 )
diff --git a/pkg/eventchannel/BUILD b/pkg/eventchannel/BUILD
index 0b4b7cc44..9d68682c7 100644
--- a/pkg/eventchannel/BUILD
+++ b/pkg/eventchannel/BUILD
@@ -15,6 +15,7 @@ go_library(
     deps = [
         ":eventchannel_go_proto",
         "//pkg/log",
+        "//pkg/sync",
         "//pkg/unet",
         "@com_github_golang_protobuf//proto:go_default_library",
         "@com_github_golang_protobuf//ptypes:go_default_library_gen",
@@ -40,6 +41,7 @@ go_test(
     srcs = ["event_test.go"],
     embed = [":eventchannel"],
     deps = [
+        "//pkg/sync",
         "@com_github_golang_protobuf//proto:go_default_library",
     ],
 )
diff --git a/pkg/eventchannel/event.go b/pkg/eventchannel/event.go
index d37ad0428..9a29c58bd 100644
--- a/pkg/eventchannel/event.go
+++ b/pkg/eventchannel/event.go
@@ -22,13 +22,13 @@ package eventchannel
 import (
 	"encoding/binary"
 	"fmt"
-	"sync"
 	"syscall"
 
 	"github.com/golang/protobuf/proto"
 	"github.com/golang/protobuf/ptypes"
 	pb "gvisor.dev/gvisor/pkg/eventchannel/eventchannel_go_proto"
 	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/unet"
 )
 
diff --git a/pkg/eventchannel/event_test.go b/pkg/eventchannel/event_test.go
index 3649097d6..7f41b4a27 100644
--- a/pkg/eventchannel/event_test.go
+++ b/pkg/eventchannel/event_test.go
@@ -16,11 +16,11 @@ package eventchannel
 
 import (
 	"fmt"
-	"sync"
 	"testing"
 	"time"
 
 	"github.com/golang/protobuf/proto"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // testEmitter is an emitter that can be used in tests. It records all events
diff --git a/pkg/fdchannel/BUILD b/pkg/fdchannel/BUILD
index 56495cbd9..b0478c672 100644
--- a/pkg/fdchannel/BUILD
+++ b/pkg/fdchannel/BUILD
@@ -15,4 +15,5 @@ go_test(
     size = "small",
     srcs = ["fdchannel_test.go"],
     embed = [":fdchannel"],
+    deps = ["//pkg/sync"],
 )
diff --git a/pkg/fdchannel/fdchannel_test.go b/pkg/fdchannel/fdchannel_test.go
index 5d01dc636..7a8a63a59 100644
--- a/pkg/fdchannel/fdchannel_test.go
+++ b/pkg/fdchannel/fdchannel_test.go
@@ -17,10 +17,11 @@ package fdchannel
 import (
 	"io/ioutil"
 	"os"
-	"sync"
 	"syscall"
 	"testing"
 	"time"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 func TestSendRecvFD(t *testing.T) {
diff --git a/pkg/fdnotifier/BUILD b/pkg/fdnotifier/BUILD
index aca2d8a82..91a202a30 100644
--- a/pkg/fdnotifier/BUILD
+++ b/pkg/fdnotifier/BUILD
@@ -11,6 +11,7 @@ go_library(
     importpath = "gvisor.dev/gvisor/pkg/fdnotifier",
     visibility = ["//:sandbox"],
     deps = [
+        "//pkg/sync",
         "//pkg/waiter",
         "@org_golang_x_sys//unix:go_default_library",
     ],
diff --git a/pkg/fdnotifier/fdnotifier.go b/pkg/fdnotifier/fdnotifier.go
index f4aae1953..a6b63c982 100644
--- a/pkg/fdnotifier/fdnotifier.go
+++ b/pkg/fdnotifier/fdnotifier.go
@@ -22,10 +22,10 @@ package fdnotifier
 
 import (
 	"fmt"
-	"sync"
 	"syscall"
 
 	"golang.org/x/sys/unix"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
diff --git a/pkg/flipcall/BUILD b/pkg/flipcall/BUILD
index e590a71ba..85bd83af1 100644
--- a/pkg/flipcall/BUILD
+++ b/pkg/flipcall/BUILD
@@ -19,7 +19,7 @@ go_library(
         "//pkg/abi/linux",
         "//pkg/log",
         "//pkg/memutil",
-        "//pkg/syncutil",
+        "//pkg/sync",
     ],
 )
 
@@ -31,4 +31,5 @@ go_test(
         "flipcall_test.go",
     ],
     embed = [":flipcall"],
+    deps = ["//pkg/sync"],
 )
diff --git a/pkg/flipcall/flipcall_example_test.go b/pkg/flipcall/flipcall_example_test.go
index 8d88b845d..2e28a149a 100644
--- a/pkg/flipcall/flipcall_example_test.go
+++ b/pkg/flipcall/flipcall_example_test.go
@@ -17,7 +17,8 @@ package flipcall
 import (
 	"bytes"
 	"fmt"
-	"sync"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 func Example() {
diff --git a/pkg/flipcall/flipcall_test.go b/pkg/flipcall/flipcall_test.go
index 168a487ec..33fd55a44 100644
--- a/pkg/flipcall/flipcall_test.go
+++ b/pkg/flipcall/flipcall_test.go
@@ -16,9 +16,10 @@ package flipcall
 
 import (
 	"runtime"
-	"sync"
 	"testing"
 	"time"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 var testPacketWindowSize = pageSize
diff --git a/pkg/flipcall/flipcall_unsafe.go b/pkg/flipcall/flipcall_unsafe.go
index 27b8939fc..ac974b232 100644
--- a/pkg/flipcall/flipcall_unsafe.go
+++ b/pkg/flipcall/flipcall_unsafe.go
@@ -18,7 +18,7 @@ import (
 	"reflect"
 	"unsafe"
 
-	"gvisor.dev/gvisor/pkg/syncutil"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // Packets consist of a 16-byte header followed by an arbitrarily-sized
@@ -75,13 +75,13 @@ func (ep *Endpoint) Data() []byte {
 var ioSync int64
 
 func raceBecomeActive() {
-	if syncutil.RaceEnabled {
-		syncutil.RaceAcquire((unsafe.Pointer)(&ioSync))
+	if sync.RaceEnabled {
+		sync.RaceAcquire((unsafe.Pointer)(&ioSync))
 	}
 }
 
 func raceBecomeInactive() {
-	if syncutil.RaceEnabled {
-		syncutil.RaceReleaseMerge((unsafe.Pointer)(&ioSync))
+	if sync.RaceEnabled {
+		sync.RaceReleaseMerge((unsafe.Pointer)(&ioSync))
 	}
 }
diff --git a/pkg/gate/BUILD b/pkg/gate/BUILD
index 4b9321711..f22bd070d 100644
--- a/pkg/gate/BUILD
+++ b/pkg/gate/BUILD
@@ -19,5 +19,6 @@ go_test(
     ],
     deps = [
         ":gate",
+        "//pkg/sync",
     ],
 )
diff --git a/pkg/gate/gate_test.go b/pkg/gate/gate_test.go
index 5dbd8d712..850693df8 100644
--- a/pkg/gate/gate_test.go
+++ b/pkg/gate/gate_test.go
@@ -15,11 +15,11 @@
 package gate_test
 
 import (
-	"sync"
 	"testing"
 	"time"
 
 	"gvisor.dev/gvisor/pkg/gate"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 func TestBasicEnter(t *testing.T) {
diff --git a/pkg/linewriter/BUILD b/pkg/linewriter/BUILD
index a5d980d14..bcde6d308 100644
--- a/pkg/linewriter/BUILD
+++ b/pkg/linewriter/BUILD
@@ -8,6 +8,7 @@ go_library(
     srcs = ["linewriter.go"],
     importpath = "gvisor.dev/gvisor/pkg/linewriter",
     visibility = ["//visibility:public"],
+    deps = ["//pkg/sync"],
 )
 
 go_test(
diff --git a/pkg/linewriter/linewriter.go b/pkg/linewriter/linewriter.go
index cd6e4e2ce..a1b1285d4 100644
--- a/pkg/linewriter/linewriter.go
+++ b/pkg/linewriter/linewriter.go
@@ -17,7 +17,8 @@ package linewriter
 
 import (
 	"bytes"
-	"sync"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // Writer is an io.Writer which buffers input, flushing
diff --git a/pkg/log/BUILD b/pkg/log/BUILD
index fc5f5779b..0df0f2849 100644
--- a/pkg/log/BUILD
+++ b/pkg/log/BUILD
@@ -16,7 +16,10 @@ go_library(
     visibility = [
         "//visibility:public",
     ],
-    deps = ["//pkg/linewriter"],
+    deps = [
+        "//pkg/linewriter",
+        "//pkg/sync",
+    ],
 )
 
 go_test(
diff --git a/pkg/log/log.go b/pkg/log/log.go
index 9387586e6..91a81b288 100644
--- a/pkg/log/log.go
+++ b/pkg/log/log.go
@@ -25,12 +25,12 @@ import (
 	stdlog "log"
 	"os"
 	"runtime"
-	"sync"
 	"sync/atomic"
 	"syscall"
 	"time"
 
 	"gvisor.dev/gvisor/pkg/linewriter"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // Level is the log level.
diff --git a/pkg/metric/BUILD b/pkg/metric/BUILD
index dd6ca6d39..9145f3233 100644
--- a/pkg/metric/BUILD
+++ b/pkg/metric/BUILD
@@ -14,6 +14,7 @@ go_library(
         ":metric_go_proto",
         "//pkg/eventchannel",
         "//pkg/log",
+        "//pkg/sync",
     ],
 )
 
diff --git a/pkg/metric/metric.go b/pkg/metric/metric.go
index eadde06e4..93d4f2b8c 100644
--- a/pkg/metric/metric.go
+++ b/pkg/metric/metric.go
@@ -18,12 +18,12 @@ package metric
 import (
 	"errors"
 	"fmt"
-	"sync"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/eventchannel"
 	"gvisor.dev/gvisor/pkg/log"
 	pb "gvisor.dev/gvisor/pkg/metric/metric_go_proto"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 var (
diff --git a/pkg/p9/BUILD b/pkg/p9/BUILD
index f32244c69..a3e05c96d 100644
--- a/pkg/p9/BUILD
+++ b/pkg/p9/BUILD
@@ -29,6 +29,7 @@ go_library(
         "//pkg/fdchannel",
         "//pkg/flipcall",
         "//pkg/log",
+        "//pkg/sync",
         "//pkg/unet",
         "@org_golang_x_sys//unix:go_default_library",
     ],
diff --git a/pkg/p9/client.go b/pkg/p9/client.go
index 221516c6c..4045e41fa 100644
--- a/pkg/p9/client.go
+++ b/pkg/p9/client.go
@@ -17,12 +17,12 @@ package p9
 import (
 	"errors"
 	"fmt"
-	"sync"
 	"syscall"
 
 	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/flipcall"
 	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/unet"
 )
 
diff --git a/pkg/p9/p9test/BUILD b/pkg/p9/p9test/BUILD
index 28707c0ca..f4edd68b2 100644
--- a/pkg/p9/p9test/BUILD
+++ b/pkg/p9/p9test/BUILD
@@ -70,6 +70,7 @@ go_library(
         "//pkg/fd",
         "//pkg/log",
         "//pkg/p9",
+        "//pkg/sync",
         "//pkg/unet",
         "@com_github_golang_mock//gomock:go_default_library",
     ],
@@ -83,6 +84,7 @@ go_test(
     deps = [
         "//pkg/fd",
         "//pkg/p9",
+        "//pkg/sync",
         "@com_github_golang_mock//gomock:go_default_library",
     ],
 )
diff --git a/pkg/p9/p9test/client_test.go b/pkg/p9/p9test/client_test.go
index 6e758148d..6e7bb3db2 100644
--- a/pkg/p9/p9test/client_test.go
+++ b/pkg/p9/p9test/client_test.go
@@ -22,7 +22,6 @@ import (
 	"os"
 	"reflect"
 	"strings"
-	"sync"
 	"syscall"
 	"testing"
 	"time"
@@ -30,6 +29,7 @@ import (
 	"github.com/golang/mock/gomock"
 	"gvisor.dev/gvisor/pkg/fd"
 	"gvisor.dev/gvisor/pkg/p9"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 func TestPanic(t *testing.T) {
diff --git a/pkg/p9/p9test/p9test.go b/pkg/p9/p9test/p9test.go
index 4d3271b37..dd8b01b6d 100644
--- a/pkg/p9/p9test/p9test.go
+++ b/pkg/p9/p9test/p9test.go
@@ -17,13 +17,13 @@ package p9test
 
 import (
 	"fmt"
-	"sync"
 	"sync/atomic"
 	"syscall"
 	"testing"
 
 	"github.com/golang/mock/gomock"
 	"gvisor.dev/gvisor/pkg/p9"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/unet"
 )
 
diff --git a/pkg/p9/path_tree.go b/pkg/p9/path_tree.go
index 865459411..72ef53313 100644
--- a/pkg/p9/path_tree.go
+++ b/pkg/p9/path_tree.go
@@ -16,7 +16,8 @@ package p9
 
 import (
 	"fmt"
-	"sync"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // pathNode is a single node in a path traversal.
diff --git a/pkg/p9/pool.go b/pkg/p9/pool.go
index 52de889e1..2b14a5ce3 100644
--- a/pkg/p9/pool.go
+++ b/pkg/p9/pool.go
@@ -15,7 +15,7 @@
 package p9
 
 import (
-	"sync"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // pool is a simple allocator.
diff --git a/pkg/p9/server.go b/pkg/p9/server.go
index 40b8fa023..fdfa83648 100644
--- a/pkg/p9/server.go
+++ b/pkg/p9/server.go
@@ -17,7 +17,6 @@ package p9
 import (
 	"io"
 	"runtime/debug"
-	"sync"
 	"sync/atomic"
 	"syscall"
 
@@ -25,6 +24,7 @@ import (
 	"gvisor.dev/gvisor/pkg/fdchannel"
 	"gvisor.dev/gvisor/pkg/flipcall"
 	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/unet"
 )
 
diff --git a/pkg/p9/transport.go b/pkg/p9/transport.go
index 6e8b4bbcd..9c11e28ce 100644
--- a/pkg/p9/transport.go
+++ b/pkg/p9/transport.go
@@ -19,11 +19,11 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
-	"sync"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/fd"
 	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/unet"
 )
 
diff --git a/pkg/procid/BUILD b/pkg/procid/BUILD
index 078f084b2..b506813f0 100644
--- a/pkg/procid/BUILD
+++ b/pkg/procid/BUILD
@@ -21,6 +21,7 @@ go_test(
         "procid_test.go",
     ],
     embed = [":procid"],
+    deps = ["//pkg/sync"],
 )
 
 go_test(
@@ -31,4 +32,5 @@ go_test(
         "procid_test.go",
     ],
     embed = [":procid"],
+    deps = ["//pkg/sync"],
 )
diff --git a/pkg/procid/procid_test.go b/pkg/procid/procid_test.go
index 88dd0b3ae..9ec08c3d6 100644
--- a/pkg/procid/procid_test.go
+++ b/pkg/procid/procid_test.go
@@ -17,9 +17,10 @@ package procid
 import (
 	"os"
 	"runtime"
-	"sync"
 	"syscall"
 	"testing"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // runOnMain is used to send functions to run on the main (initial) thread.
diff --git a/pkg/rand/BUILD b/pkg/rand/BUILD
index f4f2001f3..9d5b4859b 100644
--- a/pkg/rand/BUILD
+++ b/pkg/rand/BUILD
@@ -10,5 +10,8 @@ go_library(
     ],
     importpath = "gvisor.dev/gvisor/pkg/rand",
     visibility = ["//:sandbox"],
-    deps = ["@org_golang_x_sys//unix:go_default_library"],
+    deps = [
+        "//pkg/sync",
+        "@org_golang_x_sys//unix:go_default_library",
+    ],
 )
diff --git a/pkg/rand/rand_linux.go b/pkg/rand/rand_linux.go
index 2b92db3e6..0bdad5fad 100644
--- a/pkg/rand/rand_linux.go
+++ b/pkg/rand/rand_linux.go
@@ -19,9 +19,9 @@ package rand
 import (
 	"crypto/rand"
 	"io"
-	"sync"
 
 	"golang.org/x/sys/unix"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // reader implements an io.Reader that returns pseudorandom bytes.
diff --git a/pkg/refs/BUILD b/pkg/refs/BUILD
index 7ad59dfd7..974d9af9b 100644
--- a/pkg/refs/BUILD
+++ b/pkg/refs/BUILD
@@ -27,6 +27,7 @@ go_library(
     visibility = ["//:sandbox"],
     deps = [
         "//pkg/log",
+        "//pkg/sync",
     ],
 )
 
@@ -35,4 +36,5 @@ go_test(
     size = "small",
     srcs = ["refcounter_test.go"],
     embed = [":refs"],
+    deps = ["//pkg/sync"],
 )
diff --git a/pkg/refs/refcounter.go b/pkg/refs/refcounter.go
index ad69e0757..c45ba8200 100644
--- a/pkg/refs/refcounter.go
+++ b/pkg/refs/refcounter.go
@@ -21,10 +21,10 @@ import (
 	"fmt"
 	"reflect"
 	"runtime"
-	"sync"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // RefCounter is the interface to be implemented by objects that are reference
diff --git a/pkg/refs/refcounter_test.go b/pkg/refs/refcounter_test.go
index ffd3d3f07..1ab4a4440 100644
--- a/pkg/refs/refcounter_test.go
+++ b/pkg/refs/refcounter_test.go
@@ -16,8 +16,9 @@ package refs
 
 import (
 	"reflect"
-	"sync"
 	"testing"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 type testCounter struct {
diff --git a/pkg/sentry/arch/BUILD b/pkg/sentry/arch/BUILD
index 18c73cc24..ae3e364cd 100644
--- a/pkg/sentry/arch/BUILD
+++ b/pkg/sentry/arch/BUILD
@@ -32,6 +32,7 @@ go_library(
         "//pkg/sentry/context",
         "//pkg/sentry/limits",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserror",
     ],
 )
diff --git a/pkg/sentry/arch/arch_x86.go b/pkg/sentry/arch/arch_x86.go
index 9294ac773..9f41e566f 100644
--- a/pkg/sentry/arch/arch_x86.go
+++ b/pkg/sentry/arch/arch_x86.go
@@ -19,7 +19,6 @@ package arch
 import (
 	"fmt"
 	"io"
-	"sync"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/binary"
@@ -27,6 +26,7 @@ import (
 	"gvisor.dev/gvisor/pkg/log"
 	rpb "gvisor.dev/gvisor/pkg/sentry/arch/registers_go_proto"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/control/BUILD b/pkg/sentry/control/BUILD
index 5522cecd0..2561a6109 100644
--- a/pkg/sentry/control/BUILD
+++ b/pkg/sentry/control/BUILD
@@ -30,6 +30,7 @@ go_library(
         "//pkg/sentry/strace",
         "//pkg/sentry/usage",
         "//pkg/sentry/watchdog",
+        "//pkg/sync",
         "//pkg/tcpip/link/sniffer",
         "//pkg/urpc",
     ],
diff --git a/pkg/sentry/control/pprof.go b/pkg/sentry/control/pprof.go
index e1f2fea60..151808911 100644
--- a/pkg/sentry/control/pprof.go
+++ b/pkg/sentry/control/pprof.go
@@ -19,10 +19,10 @@ import (
 	"runtime"
 	"runtime/pprof"
 	"runtime/trace"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/fd"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/urpc"
 )
 
diff --git a/pkg/sentry/device/BUILD b/pkg/sentry/device/BUILD
index 1098ed777..97fa1512c 100644
--- a/pkg/sentry/device/BUILD
+++ b/pkg/sentry/device/BUILD
@@ -8,7 +8,10 @@ go_library(
     srcs = ["device.go"],
     importpath = "gvisor.dev/gvisor/pkg/sentry/device",
     visibility = ["//pkg/sentry:internal"],
-    deps = ["//pkg/abi/linux"],
+    deps = [
+        "//pkg/abi/linux",
+        "//pkg/sync",
+    ],
 )
 
 go_test(
diff --git a/pkg/sentry/device/device.go b/pkg/sentry/device/device.go
index 47945d1a7..69e71e322 100644
--- a/pkg/sentry/device/device.go
+++ b/pkg/sentry/device/device.go
@@ -19,10 +19,10 @@ package device
 import (
 	"bytes"
 	"fmt"
-	"sync"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // Registry tracks all simple devices and related state on the system for
diff --git a/pkg/sentry/fs/BUILD b/pkg/sentry/fs/BUILD
index c035ffff7..7d5d72d5a 100644
--- a/pkg/sentry/fs/BUILD
+++ b/pkg/sentry/fs/BUILD
@@ -68,7 +68,7 @@ go_library(
         "//pkg/sentry/usage",
         "//pkg/sentry/usermem",
         "//pkg/state",
-        "//pkg/syncutil",
+        "//pkg/sync",
         "//pkg/syserror",
         "//pkg/waiter",
     ],
@@ -115,6 +115,7 @@ go_test(
         "//pkg/sentry/fs/tmpfs",
         "//pkg/sentry/kernel/contexttest",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserror",
     ],
 )
diff --git a/pkg/sentry/fs/copy_up.go b/pkg/sentry/fs/copy_up.go
index 9ac62c84d..734177e90 100644
--- a/pkg/sentry/fs/copy_up.go
+++ b/pkg/sentry/fs/copy_up.go
@@ -17,12 +17,12 @@ package fs
 import (
 	"fmt"
 	"io"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/fs/copy_up_test.go b/pkg/sentry/fs/copy_up_test.go
index 1d80bf15a..738580c5f 100644
--- a/pkg/sentry/fs/copy_up_test.go
+++ b/pkg/sentry/fs/copy_up_test.go
@@ -19,13 +19,13 @@ import (
 	"crypto/rand"
 	"fmt"
 	"io"
-	"sync"
 	"testing"
 
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	_ "gvisor.dev/gvisor/pkg/sentry/fs/tmpfs"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/contexttest"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 const (
diff --git a/pkg/sentry/fs/dirent.go b/pkg/sentry/fs/dirent.go
index 3cb73bd78..31fc4d87b 100644
--- a/pkg/sentry/fs/dirent.go
+++ b/pkg/sentry/fs/dirent.go
@@ -18,7 +18,6 @@ import (
 	"fmt"
 	"path"
 	"sort"
-	"sync"
 	"sync/atomic"
 	"syscall"
 
@@ -28,6 +27,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
 	"gvisor.dev/gvisor/pkg/sentry/uniqueid"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/fs/dirent_cache.go b/pkg/sentry/fs/dirent_cache.go
index 60a15a275..25514ace4 100644
--- a/pkg/sentry/fs/dirent_cache.go
+++ b/pkg/sentry/fs/dirent_cache.go
@@ -16,7 +16,8 @@ package fs
 
 import (
 	"fmt"
-	"sync"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // DirentCache is an LRU cache of Dirents. The Dirent's refCount is
diff --git a/pkg/sentry/fs/dirent_cache_limiter.go b/pkg/sentry/fs/dirent_cache_limiter.go
index ebb80bd50..525ee25f9 100644
--- a/pkg/sentry/fs/dirent_cache_limiter.go
+++ b/pkg/sentry/fs/dirent_cache_limiter.go
@@ -16,7 +16,8 @@ package fs
 
 import (
 	"fmt"
-	"sync"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // DirentCacheLimiter acts as a global limit for all dirent caches in the
diff --git a/pkg/sentry/fs/fdpipe/BUILD b/pkg/sentry/fs/fdpipe/BUILD
index 277ee4c31..cc43de69d 100644
--- a/pkg/sentry/fs/fdpipe/BUILD
+++ b/pkg/sentry/fs/fdpipe/BUILD
@@ -23,6 +23,7 @@ go_library(
         "//pkg/sentry/fs/fsutil",
         "//pkg/sentry/safemem",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserror",
         "//pkg/waiter",
     ],
diff --git a/pkg/sentry/fs/fdpipe/pipe.go b/pkg/sentry/fs/fdpipe/pipe.go
index 669ffcb75..5b6cfeb0a 100644
--- a/pkg/sentry/fs/fdpipe/pipe.go
+++ b/pkg/sentry/fs/fdpipe/pipe.go
@@ -17,7 +17,6 @@ package fdpipe
 
 import (
 	"os"
-	"sync"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/fd"
@@ -29,6 +28,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.dev/gvisor/pkg/sentry/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/fs/fdpipe/pipe_state.go b/pkg/sentry/fs/fdpipe/pipe_state.go
index 29175fb3d..cee87f726 100644
--- a/pkg/sentry/fs/fdpipe/pipe_state.go
+++ b/pkg/sentry/fs/fdpipe/pipe_state.go
@@ -17,10 +17,10 @@ package fdpipe
 import (
 	"fmt"
 	"io/ioutil"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // beforeSave is invoked by stateify.
diff --git a/pkg/sentry/fs/file.go b/pkg/sentry/fs/file.go
index a2f966cb6..7c4586296 100644
--- a/pkg/sentry/fs/file.go
+++ b/pkg/sentry/fs/file.go
@@ -16,7 +16,6 @@ package fs
 
 import (
 	"math"
-	"sync"
 	"sync/atomic"
 	"time"
 
@@ -29,6 +28,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/uniqueid"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/fs/file_overlay.go b/pkg/sentry/fs/file_overlay.go
index 225e40186..8a633b1ba 100644
--- a/pkg/sentry/fs/file_overlay.go
+++ b/pkg/sentry/fs/file_overlay.go
@@ -16,13 +16,13 @@ package fs
 
 import (
 	"io"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/refs"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/fs/filesystems.go b/pkg/sentry/fs/filesystems.go
index b157fd228..c5b51620a 100644
--- a/pkg/sentry/fs/filesystems.go
+++ b/pkg/sentry/fs/filesystems.go
@@ -18,9 +18,9 @@ import (
 	"fmt"
 	"sort"
 	"strings"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // FilesystemFlags matches include/linux/fs.h:file_system_type.fs_flags.
diff --git a/pkg/sentry/fs/fs.go b/pkg/sentry/fs/fs.go
index 8b2a5e6b2..26abf49e2 100644
--- a/pkg/sentry/fs/fs.go
+++ b/pkg/sentry/fs/fs.go
@@ -54,10 +54,9 @@
 package fs
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 var (
diff --git a/pkg/sentry/fs/fsutil/BUILD b/pkg/sentry/fs/fsutil/BUILD
index 9ca695a95..945b6270d 100644
--- a/pkg/sentry/fs/fsutil/BUILD
+++ b/pkg/sentry/fs/fsutil/BUILD
@@ -93,6 +93,7 @@ go_library(
         "//pkg/sentry/usage",
         "//pkg/sentry/usermem",
         "//pkg/state",
+        "//pkg/sync",
         "//pkg/syserror",
         "//pkg/waiter",
     ],
diff --git a/pkg/sentry/fs/fsutil/host_file_mapper.go b/pkg/sentry/fs/fsutil/host_file_mapper.go
index b06a71cc2..837fc70b5 100644
--- a/pkg/sentry/fs/fsutil/host_file_mapper.go
+++ b/pkg/sentry/fs/fsutil/host_file_mapper.go
@@ -16,7 +16,6 @@ package fsutil
 
 import (
 	"fmt"
-	"sync"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/log"
@@ -24,6 +23,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // HostFileMapper caches mappings of an arbitrary host file descriptor. It is
diff --git a/pkg/sentry/fs/fsutil/host_mappable.go b/pkg/sentry/fs/fsutil/host_mappable.go
index 30475f340..a625f0e26 100644
--- a/pkg/sentry/fs/fsutil/host_mappable.go
+++ b/pkg/sentry/fs/fsutil/host_mappable.go
@@ -16,7 +16,6 @@ package fsutil
 
 import (
 	"math"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
@@ -24,6 +23,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // HostMappable implements memmap.Mappable and platform.File over a
diff --git a/pkg/sentry/fs/fsutil/inode.go b/pkg/sentry/fs/fsutil/inode.go
index 4e100a402..adf5ec69c 100644
--- a/pkg/sentry/fs/fsutil/inode.go
+++ b/pkg/sentry/fs/fsutil/inode.go
@@ -15,13 +15,12 @@
 package fsutil
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/fs/fsutil/inode_cached.go b/pkg/sentry/fs/fsutil/inode_cached.go
index 798920d18..20a014402 100644
--- a/pkg/sentry/fs/fsutil/inode_cached.go
+++ b/pkg/sentry/fs/fsutil/inode_cached.go
@@ -17,7 +17,6 @@ package fsutil
 import (
 	"fmt"
 	"io"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/context"
@@ -30,6 +29,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/usage"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // Lock order (compare the lock order model in mm/mm.go):
diff --git a/pkg/sentry/fs/gofer/BUILD b/pkg/sentry/fs/gofer/BUILD
index 4a005c605..fd870e8e1 100644
--- a/pkg/sentry/fs/gofer/BUILD
+++ b/pkg/sentry/fs/gofer/BUILD
@@ -44,6 +44,7 @@ go_library(
         "//pkg/sentry/safemem",
         "//pkg/sentry/socket/unix/transport",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserr",
         "//pkg/syserror",
         "//pkg/unet",
diff --git a/pkg/sentry/fs/gofer/inode.go b/pkg/sentry/fs/gofer/inode.go
index 91263ebdc..245fe2ef1 100644
--- a/pkg/sentry/fs/gofer/inode.go
+++ b/pkg/sentry/fs/gofer/inode.go
@@ -16,7 +16,6 @@ package gofer
 
 import (
 	"errors"
-	"sync"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
@@ -31,6 +30,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/fs/host"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/safemem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/fs/gofer/session.go b/pkg/sentry/fs/gofer/session.go
index 4e358a46a..edc796ce0 100644
--- a/pkg/sentry/fs/gofer/session.go
+++ b/pkg/sentry/fs/gofer/session.go
@@ -16,7 +16,6 @@ package gofer
 
 import (
 	"fmt"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/p9"
 	"gvisor.dev/gvisor/pkg/refs"
@@ -25,6 +24,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/unet"
 )
 
diff --git a/pkg/sentry/fs/host/BUILD b/pkg/sentry/fs/host/BUILD
index 23daeb528..2b581aa69 100644
--- a/pkg/sentry/fs/host/BUILD
+++ b/pkg/sentry/fs/host/BUILD
@@ -50,6 +50,7 @@ go_library(
         "//pkg/sentry/unimpl",
         "//pkg/sentry/uniqueid",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserr",
         "//pkg/syserror",
         "//pkg/tcpip",
diff --git a/pkg/sentry/fs/host/inode.go b/pkg/sentry/fs/host/inode.go
index a6e4a09e3..873a1c52d 100644
--- a/pkg/sentry/fs/host/inode.go
+++ b/pkg/sentry/fs/host/inode.go
@@ -15,7 +15,6 @@
 package host
 
 import (
-	"sync"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
@@ -28,6 +27,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/fs/host/socket.go b/pkg/sentry/fs/host/socket.go
index 107336a3e..c076d5bdd 100644
--- a/pkg/sentry/fs/host/socket.go
+++ b/pkg/sentry/fs/host/socket.go
@@ -16,7 +16,6 @@ package host
 
 import (
 	"fmt"
-	"sync"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
@@ -30,6 +29,7 @@ import (
 	unixsocket "gvisor.dev/gvisor/pkg/sentry/socket/unix"
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
 	"gvisor.dev/gvisor/pkg/sentry/uniqueid"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserr"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/tcpip"
diff --git a/pkg/sentry/fs/host/tty.go b/pkg/sentry/fs/host/tty.go
index 90331e3b2..753ef8cd6 100644
--- a/pkg/sentry/fs/host/tty.go
+++ b/pkg/sentry/fs/host/tty.go
@@ -15,8 +15,6 @@
 package host
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/context"
@@ -24,6 +22,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/sentry/unimpl"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/fs/inode.go b/pkg/sentry/fs/inode.go
index 91e2fde2f..468043df0 100644
--- a/pkg/sentry/fs/inode.go
+++ b/pkg/sentry/fs/inode.go
@@ -15,8 +15,6 @@
 package fs
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/metric"
@@ -26,6 +24,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/fs/inode_inotify.go b/pkg/sentry/fs/inode_inotify.go
index 0f2a66a79..efd3c962b 100644
--- a/pkg/sentry/fs/inode_inotify.go
+++ b/pkg/sentry/fs/inode_inotify.go
@@ -16,7 +16,8 @@ package fs
 
 import (
 	"fmt"
-	"sync"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // Watches is the collection of inotify watches on an inode.
diff --git a/pkg/sentry/fs/inotify.go b/pkg/sentry/fs/inotify.go
index ba3e0233d..cc7dd1c92 100644
--- a/pkg/sentry/fs/inotify.go
+++ b/pkg/sentry/fs/inotify.go
@@ -16,7 +16,6 @@ package fs
 
 import (
 	"io"
-	"sync"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
@@ -25,6 +24,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/uniqueid"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/fs/inotify_watch.go b/pkg/sentry/fs/inotify_watch.go
index 0aa0a5e9b..900cba3ca 100644
--- a/pkg/sentry/fs/inotify_watch.go
+++ b/pkg/sentry/fs/inotify_watch.go
@@ -15,10 +15,10 @@
 package fs
 
 import (
-	"sync"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // Watch represent a particular inotify watch created by inotify_add_watch.
diff --git a/pkg/sentry/fs/lock/BUILD b/pkg/sentry/fs/lock/BUILD
index 8d62642e7..2c332a82a 100644
--- a/pkg/sentry/fs/lock/BUILD
+++ b/pkg/sentry/fs/lock/BUILD
@@ -44,6 +44,7 @@ go_library(
     visibility = ["//pkg/sentry:internal"],
     deps = [
         "//pkg/log",
+        "//pkg/sync",
         "//pkg/waiter",
     ],
 )
diff --git a/pkg/sentry/fs/lock/lock.go b/pkg/sentry/fs/lock/lock.go
index 636484424..41b040818 100644
--- a/pkg/sentry/fs/lock/lock.go
+++ b/pkg/sentry/fs/lock/lock.go
@@ -52,9 +52,9 @@ package lock
 import (
 	"fmt"
 	"math"
-	"sync"
 	"syscall"
 
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
diff --git a/pkg/sentry/fs/mounts.go b/pkg/sentry/fs/mounts.go
index ac0398bd9..db3dfd096 100644
--- a/pkg/sentry/fs/mounts.go
+++ b/pkg/sentry/fs/mounts.go
@@ -19,7 +19,6 @@ import (
 	"math"
 	"path"
 	"strings"
-	"sync"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
@@ -27,6 +26,7 @@ import (
 	"gvisor.dev/gvisor/pkg/refs"
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/fs/overlay.go b/pkg/sentry/fs/overlay.go
index 25573e986..4cad55327 100644
--- a/pkg/sentry/fs/overlay.go
+++ b/pkg/sentry/fs/overlay.go
@@ -17,13 +17,12 @@ package fs
 import (
 	"fmt"
 	"strings"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
-	"gvisor.dev/gvisor/pkg/syncutil"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
@@ -199,7 +198,7 @@ type overlayEntry struct {
 	upper *Inode
 
 	// dirCacheMu protects dirCache.
-	dirCacheMu syncutil.DowngradableRWMutex `state:"nosave"`
+	dirCacheMu sync.DowngradableRWMutex `state:"nosave"`
 
 	// dirCache is cache of DentAttrs from upper and lower Inodes.
 	dirCache *SortedDentryMap
diff --git a/pkg/sentry/fs/proc/BUILD b/pkg/sentry/fs/proc/BUILD
index 75cbb0622..94d46ab1b 100644
--- a/pkg/sentry/fs/proc/BUILD
+++ b/pkg/sentry/fs/proc/BUILD
@@ -51,6 +51,7 @@ go_library(
         "//pkg/sentry/socket/unix/transport",
         "//pkg/sentry/usage",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserror",
         "//pkg/tcpip/header",
         "//pkg/waiter",
diff --git a/pkg/sentry/fs/proc/seqfile/BUILD b/pkg/sentry/fs/proc/seqfile/BUILD
index fe7067be1..38b246dff 100644
--- a/pkg/sentry/fs/proc/seqfile/BUILD
+++ b/pkg/sentry/fs/proc/seqfile/BUILD
@@ -16,6 +16,7 @@ go_library(
         "//pkg/sentry/fs/proc/device",
         "//pkg/sentry/kernel/time",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserror",
         "//pkg/waiter",
     ],
diff --git a/pkg/sentry/fs/proc/seqfile/seqfile.go b/pkg/sentry/fs/proc/seqfile/seqfile.go
index 5fe823000..f9af191d5 100644
--- a/pkg/sentry/fs/proc/seqfile/seqfile.go
+++ b/pkg/sentry/fs/proc/seqfile/seqfile.go
@@ -17,7 +17,6 @@ package seqfile
 
 import (
 	"io"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/context"
@@ -26,6 +25,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/fs/proc/device"
 	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/fs/proc/sys_net.go b/pkg/sentry/fs/proc/sys_net.go
index bd93f83fa..a37e1fa06 100644
--- a/pkg/sentry/fs/proc/sys_net.go
+++ b/pkg/sentry/fs/proc/sys_net.go
@@ -17,7 +17,6 @@ package proc
 import (
 	"fmt"
 	"io"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/context"
@@ -27,6 +26,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/fs/ramfs"
 	"gvisor.dev/gvisor/pkg/sentry/inet"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
diff --git a/pkg/sentry/fs/ramfs/BUILD b/pkg/sentry/fs/ramfs/BUILD
index 012cb3e44..3fb7b0633 100644
--- a/pkg/sentry/fs/ramfs/BUILD
+++ b/pkg/sentry/fs/ramfs/BUILD
@@ -21,6 +21,7 @@ go_library(
         "//pkg/sentry/fs/fsutil",
         "//pkg/sentry/socket/unix/transport",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserror",
         "//pkg/waiter",
     ],
diff --git a/pkg/sentry/fs/ramfs/dir.go b/pkg/sentry/fs/ramfs/dir.go
index 78e082b8e..dcbb8eb2e 100644
--- a/pkg/sentry/fs/ramfs/dir.go
+++ b/pkg/sentry/fs/ramfs/dir.go
@@ -17,7 +17,6 @@ package ramfs
 
 import (
 	"fmt"
-	"sync"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
@@ -25,6 +24,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/fs/restore.go b/pkg/sentry/fs/restore.go
index f10168125..64c6a6ae9 100644
--- a/pkg/sentry/fs/restore.go
+++ b/pkg/sentry/fs/restore.go
@@ -15,7 +15,7 @@
 package fs
 
 import (
-	"sync"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // RestoreEnvironment is the restore environment for file systems. It consists
diff --git a/pkg/sentry/fs/tmpfs/BUILD b/pkg/sentry/fs/tmpfs/BUILD
index 59ce400c2..3400b940c 100644
--- a/pkg/sentry/fs/tmpfs/BUILD
+++ b/pkg/sentry/fs/tmpfs/BUILD
@@ -31,6 +31,7 @@ go_library(
         "//pkg/sentry/socket/unix/transport",
         "//pkg/sentry/usage",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserror",
         "//pkg/waiter",
     ],
diff --git a/pkg/sentry/fs/tmpfs/inode_file.go b/pkg/sentry/fs/tmpfs/inode_file.go
index f86dfaa36..f1c87fe41 100644
--- a/pkg/sentry/fs/tmpfs/inode_file.go
+++ b/pkg/sentry/fs/tmpfs/inode_file.go
@@ -17,7 +17,6 @@ package tmpfs
 import (
 	"fmt"
 	"io"
-	"sync"
 	"time"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
@@ -31,6 +30,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/usage"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/fs/tty/BUILD b/pkg/sentry/fs/tty/BUILD
index 95ad98cb0..f6f60d0cf 100644
--- a/pkg/sentry/fs/tty/BUILD
+++ b/pkg/sentry/fs/tty/BUILD
@@ -30,6 +30,7 @@ go_library(
         "//pkg/sentry/socket/unix/transport",
         "//pkg/sentry/unimpl",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserror",
         "//pkg/waiter",
     ],
diff --git a/pkg/sentry/fs/tty/dir.go b/pkg/sentry/fs/tty/dir.go
index 2f639c823..88aa66b24 100644
--- a/pkg/sentry/fs/tty/dir.go
+++ b/pkg/sentry/fs/tty/dir.go
@@ -19,7 +19,6 @@ import (
 	"fmt"
 	"math"
 	"strconv"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/context"
@@ -28,6 +27,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/fs/tty/line_discipline.go b/pkg/sentry/fs/tty/line_discipline.go
index 7cc0eb409..894964260 100644
--- a/pkg/sentry/fs/tty/line_discipline.go
+++ b/pkg/sentry/fs/tty/line_discipline.go
@@ -16,13 +16,13 @@ package tty
 
 import (
 	"bytes"
-	"sync"
 	"unicode/utf8"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/fs/tty/queue.go b/pkg/sentry/fs/tty/queue.go
index 231e4e6eb..8b5d4699a 100644
--- a/pkg/sentry/fs/tty/queue.go
+++ b/pkg/sentry/fs/tty/queue.go
@@ -15,13 +15,12 @@
 package tty
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/fsimpl/ext/BUILD b/pkg/sentry/fsimpl/ext/BUILD
index bc90330bc..903874141 100644
--- a/pkg/sentry/fsimpl/ext/BUILD
+++ b/pkg/sentry/fsimpl/ext/BUILD
@@ -50,6 +50,7 @@ go_library(
         "//pkg/sentry/syscalls/linux",
         "//pkg/sentry/usermem",
         "//pkg/sentry/vfs",
+        "//pkg/sync",
         "//pkg/syserror",
         "//pkg/waiter",
     ],
diff --git a/pkg/sentry/fsimpl/ext/directory.go b/pkg/sentry/fsimpl/ext/directory.go
index 91802dc1e..8944171c8 100644
--- a/pkg/sentry/fsimpl/ext/directory.go
+++ b/pkg/sentry/fsimpl/ext/directory.go
@@ -15,8 +15,6 @@
 package ext
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/binary"
 	"gvisor.dev/gvisor/pkg/log"
@@ -25,6 +23,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/fsimpl/ext/disklayout"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/fsimpl/ext/filesystem.go b/pkg/sentry/fsimpl/ext/filesystem.go
index 616fc002a..9afb1a84c 100644
--- a/pkg/sentry/fsimpl/ext/filesystem.go
+++ b/pkg/sentry/fsimpl/ext/filesystem.go
@@ -17,13 +17,13 @@ package ext
 import (
 	"errors"
 	"io"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/fspath"
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/fsimpl/ext/disklayout"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/fsimpl/ext/regular_file.go b/pkg/sentry/fsimpl/ext/regular_file.go
index aec33e00a..d11153c90 100644
--- a/pkg/sentry/fsimpl/ext/regular_file.go
+++ b/pkg/sentry/fsimpl/ext/regular_file.go
@@ -16,7 +16,6 @@ package ext
 
 import (
 	"io"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/context"
@@ -24,6 +23,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/fsimpl/kernfs/BUILD b/pkg/sentry/fsimpl/kernfs/BUILD
index 39c03ee9d..809178250 100644
--- a/pkg/sentry/fsimpl/kernfs/BUILD
+++ b/pkg/sentry/fsimpl/kernfs/BUILD
@@ -39,6 +39,7 @@ go_library(
         "//pkg/sentry/memmap",
         "//pkg/sentry/usermem",
         "//pkg/sentry/vfs",
+        "//pkg/sync",
         "//pkg/syserror",
     ],
 )
@@ -56,6 +57,7 @@ go_test(
         "//pkg/sentry/kernel/auth",
         "//pkg/sentry/usermem",
         "//pkg/sentry/vfs",
+        "//pkg/sync",
         "//pkg/syserror",
         "@com_github_google_go-cmp//cmp:go_default_library",
     ],
diff --git a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
index 752e0f659..1d469a0db 100644
--- a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
+++ b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
@@ -16,7 +16,6 @@ package kernfs
 
 import (
 	"fmt"
-	"sync"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
@@ -24,6 +23,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs.go b/pkg/sentry/fsimpl/kernfs/kernfs.go
index d69b299ae..bb12f39a2 100644
--- a/pkg/sentry/fsimpl/kernfs/kernfs.go
+++ b/pkg/sentry/fsimpl/kernfs/kernfs.go
@@ -53,7 +53,6 @@ package kernfs
 
 import (
 	"fmt"
-	"sync"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
@@ -61,6 +60,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // FilesystemType implements vfs.FilesystemType.
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs_test.go b/pkg/sentry/fsimpl/kernfs/kernfs_test.go
index 4b6b95f5f..5c9d580e1 100644
--- a/pkg/sentry/fsimpl/kernfs/kernfs_test.go
+++ b/pkg/sentry/fsimpl/kernfs/kernfs_test.go
@@ -19,7 +19,6 @@ import (
 	"fmt"
 	"io"
 	"runtime"
-	"sync"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -31,6 +30,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/fsimpl/tmpfs/BUILD b/pkg/sentry/fsimpl/tmpfs/BUILD
index a5b285987..82f5c2f41 100644
--- a/pkg/sentry/fsimpl/tmpfs/BUILD
+++ b/pkg/sentry/fsimpl/tmpfs/BUILD
@@ -47,6 +47,7 @@ go_library(
         "//pkg/sentry/usage",
         "//pkg/sentry/usermem",
         "//pkg/sentry/vfs",
+        "//pkg/sync",
         "//pkg/syserror",
     ],
 )
diff --git a/pkg/sentry/fsimpl/tmpfs/regular_file.go b/pkg/sentry/fsimpl/tmpfs/regular_file.go
index f51e247a7..f200e767d 100644
--- a/pkg/sentry/fsimpl/tmpfs/regular_file.go
+++ b/pkg/sentry/fsimpl/tmpfs/regular_file.go
@@ -17,7 +17,6 @@ package tmpfs
 import (
 	"io"
 	"math"
-	"sync"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
@@ -30,6 +29,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/usage"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
index 7be6faa5b..701826f90 100644
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go
+++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
@@ -26,7 +26,6 @@ package tmpfs
 import (
 	"fmt"
 	"math"
-	"sync"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
@@ -34,6 +33,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/pgalloc"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/kernel/BUILD b/pkg/sentry/kernel/BUILD
index 2706927ff..ac85ba0c8 100644
--- a/pkg/sentry/kernel/BUILD
+++ b/pkg/sentry/kernel/BUILD
@@ -35,7 +35,7 @@ go_template_instance(
     out = "seqatomic_taskgoroutineschedinfo_unsafe.go",
     package = "kernel",
     suffix = "TaskGoroutineSchedInfo",
-    template = "//pkg/syncutil:generic_seqatomic",
+    template = "//pkg/sync:generic_seqatomic",
     types = {
         "Value": "TaskGoroutineSchedInfo",
     },
@@ -209,7 +209,7 @@ go_library(
         "//pkg/sentry/usermem",
         "//pkg/state",
         "//pkg/state/statefile",
-        "//pkg/syncutil",
+        "//pkg/sync",
         "//pkg/syserr",
         "//pkg/syserror",
         "//pkg/tcpip",
@@ -241,6 +241,7 @@ go_test(
         "//pkg/sentry/time",
         "//pkg/sentry/usage",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserror",
     ],
 )
diff --git a/pkg/sentry/kernel/abstract_socket_namespace.go b/pkg/sentry/kernel/abstract_socket_namespace.go
index 244655b5c..920fe4329 100644
--- a/pkg/sentry/kernel/abstract_socket_namespace.go
+++ b/pkg/sentry/kernel/abstract_socket_namespace.go
@@ -15,11 +15,11 @@
 package kernel
 
 import (
-	"sync"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/refs"
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // +stateify savable
diff --git a/pkg/sentry/kernel/auth/BUILD b/pkg/sentry/kernel/auth/BUILD
index 04c244447..1aa72fa47 100644
--- a/pkg/sentry/kernel/auth/BUILD
+++ b/pkg/sentry/kernel/auth/BUILD
@@ -8,7 +8,7 @@ go_template_instance(
     out = "atomicptr_credentials_unsafe.go",
     package = "auth",
     suffix = "Credentials",
-    template = "//pkg/syncutil:generic_atomicptr",
+    template = "//pkg/sync:generic_atomicptr",
     types = {
         "Value": "Credentials",
     },
@@ -64,6 +64,7 @@ go_library(
         "//pkg/bits",
         "//pkg/log",
         "//pkg/sentry/context",
+        "//pkg/sync",
         "//pkg/syserror",
     ],
 )
diff --git a/pkg/sentry/kernel/auth/user_namespace.go b/pkg/sentry/kernel/auth/user_namespace.go
index af28ccc65..9dd52c860 100644
--- a/pkg/sentry/kernel/auth/user_namespace.go
+++ b/pkg/sentry/kernel/auth/user_namespace.go
@@ -16,8 +16,8 @@ package auth
 
 import (
 	"math"
-	"sync"
 
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/kernel/epoll/BUILD b/pkg/sentry/kernel/epoll/BUILD
index 3361e8b7d..c47f6b6fc 100644
--- a/pkg/sentry/kernel/epoll/BUILD
+++ b/pkg/sentry/kernel/epoll/BUILD
@@ -32,6 +32,7 @@ go_library(
         "//pkg/sentry/fs/anon",
         "//pkg/sentry/fs/fsutil",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/waiter",
     ],
 )
diff --git a/pkg/sentry/kernel/epoll/epoll.go b/pkg/sentry/kernel/epoll/epoll.go
index 9c0a4e1b4..430311cc0 100644
--- a/pkg/sentry/kernel/epoll/epoll.go
+++ b/pkg/sentry/kernel/epoll/epoll.go
@@ -18,7 +18,6 @@ package epoll
 
 import (
 	"fmt"
-	"sync"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/refs"
@@ -27,6 +26,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/fs/anon"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
diff --git a/pkg/sentry/kernel/eventfd/BUILD b/pkg/sentry/kernel/eventfd/BUILD
index e65b961e8..c831fbab2 100644
--- a/pkg/sentry/kernel/eventfd/BUILD
+++ b/pkg/sentry/kernel/eventfd/BUILD
@@ -16,6 +16,7 @@ go_library(
         "//pkg/sentry/fs/anon",
         "//pkg/sentry/fs/fsutil",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserror",
         "//pkg/waiter",
     ],
diff --git a/pkg/sentry/kernel/eventfd/eventfd.go b/pkg/sentry/kernel/eventfd/eventfd.go
index 12f0d429b..687690679 100644
--- a/pkg/sentry/kernel/eventfd/eventfd.go
+++ b/pkg/sentry/kernel/eventfd/eventfd.go
@@ -18,7 +18,6 @@ package eventfd
 
 import (
 	"math"
-	"sync"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
@@ -28,6 +27,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/fs/anon"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/kernel/fasync/BUILD b/pkg/sentry/kernel/fasync/BUILD
index 49d81b712..6b36bc63e 100644
--- a/pkg/sentry/kernel/fasync/BUILD
+++ b/pkg/sentry/kernel/fasync/BUILD
@@ -12,6 +12,7 @@ go_library(
         "//pkg/sentry/fs",
         "//pkg/sentry/kernel",
         "//pkg/sentry/kernel/auth",
+        "//pkg/sync",
         "//pkg/waiter",
     ],
 )
diff --git a/pkg/sentry/kernel/fasync/fasync.go b/pkg/sentry/kernel/fasync/fasync.go
index 6b0bb0324..d32c3e90a 100644
--- a/pkg/sentry/kernel/fasync/fasync.go
+++ b/pkg/sentry/kernel/fasync/fasync.go
@@ -16,12 +16,11 @@
 package fasync
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
diff --git a/pkg/sentry/kernel/fd_table.go b/pkg/sentry/kernel/fd_table.go
index 11f613a11..cd1501f85 100644
--- a/pkg/sentry/kernel/fd_table.go
+++ b/pkg/sentry/kernel/fd_table.go
@@ -18,7 +18,6 @@ import (
 	"bytes"
 	"fmt"
 	"math"
-	"sync"
 	"sync/atomic"
 	"syscall"
 
@@ -28,6 +27,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/lock"
 	"gvisor.dev/gvisor/pkg/sentry/limits"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // FDFlags define flags for an individual descriptor.
diff --git a/pkg/sentry/kernel/fd_table_test.go b/pkg/sentry/kernel/fd_table_test.go
index 2bcb6216a..eccb7d1e7 100644
--- a/pkg/sentry/kernel/fd_table_test.go
+++ b/pkg/sentry/kernel/fd_table_test.go
@@ -16,7 +16,6 @@ package kernel
 
 import (
 	"runtime"
-	"sync"
 	"testing"
 
 	"gvisor.dev/gvisor/pkg/sentry/context"
@@ -24,6 +23,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/filetest"
 	"gvisor.dev/gvisor/pkg/sentry/limits"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 const (
diff --git a/pkg/sentry/kernel/fs_context.go b/pkg/sentry/kernel/fs_context.go
index ded27d668..2448c1d99 100644
--- a/pkg/sentry/kernel/fs_context.go
+++ b/pkg/sentry/kernel/fs_context.go
@@ -16,10 +16,10 @@ package kernel
 
 import (
 	"fmt"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/refs"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // FSContext contains filesystem context.
diff --git a/pkg/sentry/kernel/futex/BUILD b/pkg/sentry/kernel/futex/BUILD
index 75ec31761..50db443ce 100644
--- a/pkg/sentry/kernel/futex/BUILD
+++ b/pkg/sentry/kernel/futex/BUILD
@@ -9,7 +9,7 @@ go_template_instance(
     out = "atomicptr_bucket_unsafe.go",
     package = "futex",
     suffix = "Bucket",
-    template = "//pkg/syncutil:generic_atomicptr",
+    template = "//pkg/sync:generic_atomicptr",
     types = {
         "Value": "bucket",
     },
@@ -42,6 +42,7 @@ go_library(
         "//pkg/sentry/context",
         "//pkg/sentry/memmap",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserror",
     ],
 )
@@ -51,5 +52,8 @@ go_test(
     size = "small",
     srcs = ["futex_test.go"],
     embed = [":futex"],
-    deps = ["//pkg/sentry/usermem"],
+    deps = [
+        "//pkg/sentry/usermem",
+        "//pkg/sync",
+    ],
 )
diff --git a/pkg/sentry/kernel/futex/futex.go b/pkg/sentry/kernel/futex/futex.go
index 278cc8143..d1931c8f4 100644
--- a/pkg/sentry/kernel/futex/futex.go
+++ b/pkg/sentry/kernel/futex/futex.go
@@ -18,11 +18,10 @@
 package futex
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/kernel/futex/futex_test.go b/pkg/sentry/kernel/futex/futex_test.go
index 65e5d1428..c23126ca5 100644
--- a/pkg/sentry/kernel/futex/futex_test.go
+++ b/pkg/sentry/kernel/futex/futex_test.go
@@ -17,13 +17,13 @@ package futex
 import (
 	"math"
 	"runtime"
-	"sync"
 	"sync/atomic"
 	"syscall"
 	"testing"
 	"unsafe"
 
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // testData implements the Target interface, and allows us to
diff --git a/pkg/sentry/kernel/kernel.go b/pkg/sentry/kernel/kernel.go
index 8653d2f63..c85e97fef 100644
--- a/pkg/sentry/kernel/kernel.go
+++ b/pkg/sentry/kernel/kernel.go
@@ -36,7 +36,6 @@ import (
 	"fmt"
 	"io"
 	"path/filepath"
-	"sync"
 	"sync/atomic"
 	"time"
 
@@ -67,6 +66,7 @@ import (
 	uspb "gvisor.dev/gvisor/pkg/sentry/unimpl/unimplemented_syscall_go_proto"
 	"gvisor.dev/gvisor/pkg/sentry/uniqueid"
 	"gvisor.dev/gvisor/pkg/state"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 )
 
diff --git a/pkg/sentry/kernel/memevent/BUILD b/pkg/sentry/kernel/memevent/BUILD
index d7a7d1169..7f36252a9 100644
--- a/pkg/sentry/kernel/memevent/BUILD
+++ b/pkg/sentry/kernel/memevent/BUILD
@@ -16,6 +16,7 @@ go_library(
         "//pkg/metric",
         "//pkg/sentry/kernel",
         "//pkg/sentry/usage",
+        "//pkg/sync",
     ],
 )
 
diff --git a/pkg/sentry/kernel/memevent/memory_events.go b/pkg/sentry/kernel/memevent/memory_events.go
index b0d98e7f0..200565bb8 100644
--- a/pkg/sentry/kernel/memevent/memory_events.go
+++ b/pkg/sentry/kernel/memevent/memory_events.go
@@ -17,7 +17,6 @@
 package memevent
 
 import (
-	"sync"
 	"time"
 
 	"gvisor.dev/gvisor/pkg/eventchannel"
@@ -26,6 +25,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	pb "gvisor.dev/gvisor/pkg/sentry/kernel/memevent/memory_events_go_proto"
 	"gvisor.dev/gvisor/pkg/sentry/usage"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 var totalTicks = metric.MustCreateNewUint64Metric("/memory_events/ticks", false /*sync*/, "Total number of memory event periods that have elapsed since startup.")
diff --git a/pkg/sentry/kernel/pipe/BUILD b/pkg/sentry/kernel/pipe/BUILD
index 9d34f6d4d..5eeaeff66 100644
--- a/pkg/sentry/kernel/pipe/BUILD
+++ b/pkg/sentry/kernel/pipe/BUILD
@@ -43,6 +43,7 @@ go_library(
         "//pkg/sentry/safemem",
         "//pkg/sentry/usermem",
         "//pkg/sentry/vfs",
+        "//pkg/sync",
         "//pkg/syserror",
         "//pkg/waiter",
     ],
diff --git a/pkg/sentry/kernel/pipe/buffer.go b/pkg/sentry/kernel/pipe/buffer.go
index 95bee2d37..1c0f34269 100644
--- a/pkg/sentry/kernel/pipe/buffer.go
+++ b/pkg/sentry/kernel/pipe/buffer.go
@@ -16,9 +16,9 @@ package pipe
 
 import (
 	"io"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/sentry/safemem"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // buffer encapsulates a queueable byte buffer.
diff --git a/pkg/sentry/kernel/pipe/node.go b/pkg/sentry/kernel/pipe/node.go
index 4a19ab7ce..716f589af 100644
--- a/pkg/sentry/kernel/pipe/node.go
+++ b/pkg/sentry/kernel/pipe/node.go
@@ -15,12 +15,11 @@
 package pipe
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/kernel/pipe/pipe.go b/pkg/sentry/kernel/pipe/pipe.go
index 1a1b38f83..e4fd7d420 100644
--- a/pkg/sentry/kernel/pipe/pipe.go
+++ b/pkg/sentry/kernel/pipe/pipe.go
@@ -17,12 +17,12 @@ package pipe
 
 import (
 	"fmt"
-	"sync"
 	"sync/atomic"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/kernel/pipe/pipe_util.go b/pkg/sentry/kernel/pipe/pipe_util.go
index ef9641e6a..8394eb78b 100644
--- a/pkg/sentry/kernel/pipe/pipe_util.go
+++ b/pkg/sentry/kernel/pipe/pipe_util.go
@@ -17,7 +17,6 @@ package pipe
 import (
 	"io"
 	"math"
-	"sync"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
@@ -25,6 +24,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
diff --git a/pkg/sentry/kernel/pipe/vfs.go b/pkg/sentry/kernel/pipe/vfs.go
index 6416e0dd8..bf7461cbb 100644
--- a/pkg/sentry/kernel/pipe/vfs.go
+++ b/pkg/sentry/kernel/pipe/vfs.go
@@ -15,13 +15,12 @@
 package pipe
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/kernel/semaphore/BUILD b/pkg/sentry/kernel/semaphore/BUILD
index f4c00cd86..13a961594 100644
--- a/pkg/sentry/kernel/semaphore/BUILD
+++ b/pkg/sentry/kernel/semaphore/BUILD
@@ -31,6 +31,7 @@ go_library(
         "//pkg/sentry/fs",
         "//pkg/sentry/kernel/auth",
         "//pkg/sentry/kernel/time",
+        "//pkg/sync",
         "//pkg/syserror",
     ],
 )
diff --git a/pkg/sentry/kernel/semaphore/semaphore.go b/pkg/sentry/kernel/semaphore/semaphore.go
index de9617e9d..18299814e 100644
--- a/pkg/sentry/kernel/semaphore/semaphore.go
+++ b/pkg/sentry/kernel/semaphore/semaphore.go
@@ -17,7 +17,6 @@ package semaphore
 
 import (
 	"fmt"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/log"
@@ -25,6 +24,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/kernel/shm/BUILD b/pkg/sentry/kernel/shm/BUILD
index cd48945e6..7321b22ed 100644
--- a/pkg/sentry/kernel/shm/BUILD
+++ b/pkg/sentry/kernel/shm/BUILD
@@ -24,6 +24,7 @@ go_library(
         "//pkg/sentry/platform",
         "//pkg/sentry/usage",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserror",
     ],
 )
diff --git a/pkg/sentry/kernel/shm/shm.go b/pkg/sentry/kernel/shm/shm.go
index 19034a21e..8ddef7eb8 100644
--- a/pkg/sentry/kernel/shm/shm.go
+++ b/pkg/sentry/kernel/shm/shm.go
@@ -35,7 +35,6 @@ package shm
 
 import (
 	"fmt"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/log"
@@ -49,6 +48,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/usage"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/kernel/signal_handlers.go b/pkg/sentry/kernel/signal_handlers.go
index a16f3d57f..768fda220 100644
--- a/pkg/sentry/kernel/signal_handlers.go
+++ b/pkg/sentry/kernel/signal_handlers.go
@@ -15,10 +15,9 @@
 package kernel
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // SignalHandlers holds information about signal actions.
diff --git a/pkg/sentry/kernel/signalfd/BUILD b/pkg/sentry/kernel/signalfd/BUILD
index 9f7e19b4d..89e4d84b1 100644
--- a/pkg/sentry/kernel/signalfd/BUILD
+++ b/pkg/sentry/kernel/signalfd/BUILD
@@ -16,6 +16,7 @@ go_library(
         "//pkg/sentry/fs/fsutil",
         "//pkg/sentry/kernel",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserror",
         "//pkg/waiter",
     ],
diff --git a/pkg/sentry/kernel/signalfd/signalfd.go b/pkg/sentry/kernel/signalfd/signalfd.go
index 4b08d7d72..28be4a939 100644
--- a/pkg/sentry/kernel/signalfd/signalfd.go
+++ b/pkg/sentry/kernel/signalfd/signalfd.go
@@ -16,8 +16,6 @@
 package signalfd
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/binary"
 	"gvisor.dev/gvisor/pkg/sentry/context"
@@ -26,6 +24,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/kernel/syscalls.go b/pkg/sentry/kernel/syscalls.go
index 2fdee0282..d2d01add4 100644
--- a/pkg/sentry/kernel/syscalls.go
+++ b/pkg/sentry/kernel/syscalls.go
@@ -16,13 +16,13 @@ package kernel
 
 import (
 	"fmt"
-	"sync"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/abi"
 	"gvisor.dev/gvisor/pkg/bits"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // maxSyscallNum is the highest supported syscall number.
diff --git a/pkg/sentry/kernel/syslog.go b/pkg/sentry/kernel/syslog.go
index 8227ecf1d..4607cde2f 100644
--- a/pkg/sentry/kernel/syslog.go
+++ b/pkg/sentry/kernel/syslog.go
@@ -17,7 +17,8 @@ package kernel
 import (
 	"fmt"
 	"math/rand"
-	"sync"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // syslog represents a sentry-global kernel log.
diff --git a/pkg/sentry/kernel/task.go b/pkg/sentry/kernel/task.go
index d25a7903b..978d66da8 100644
--- a/pkg/sentry/kernel/task.go
+++ b/pkg/sentry/kernel/task.go
@@ -17,7 +17,6 @@ package kernel
 import (
 	gocontext "context"
 	"runtime/trace"
-	"sync"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
@@ -37,7 +36,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/uniqueid"
 	"gvisor.dev/gvisor/pkg/sentry/usage"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
-	"gvisor.dev/gvisor/pkg/syncutil"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
@@ -85,7 +84,7 @@ type Task struct {
 	//
 	// gosched is protected by goschedSeq. gosched is owned by the task
 	// goroutine.
-	goschedSeq syncutil.SeqCount `state:"nosave"`
+	goschedSeq sync.SeqCount `state:"nosave"`
 	gosched    TaskGoroutineSchedInfo
 
 	// yieldCount is the number of times the task goroutine has called
diff --git a/pkg/sentry/kernel/thread_group.go b/pkg/sentry/kernel/thread_group.go
index c0197a563..768e958d2 100644
--- a/pkg/sentry/kernel/thread_group.go
+++ b/pkg/sentry/kernel/thread_group.go
@@ -15,7 +15,6 @@
 package kernel
 
 import (
-	"sync"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
@@ -25,6 +24,7 @@ import (
 	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
 	"gvisor.dev/gvisor/pkg/sentry/limits"
 	"gvisor.dev/gvisor/pkg/sentry/usage"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/kernel/threads.go b/pkg/sentry/kernel/threads.go
index 8267929a6..bf2dabb6e 100644
--- a/pkg/sentry/kernel/threads.go
+++ b/pkg/sentry/kernel/threads.go
@@ -16,9 +16,9 @@ package kernel
 
 import (
 	"fmt"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
diff --git a/pkg/sentry/kernel/time/BUILD b/pkg/sentry/kernel/time/BUILD
index 31847e1df..4e4de0512 100644
--- a/pkg/sentry/kernel/time/BUILD
+++ b/pkg/sentry/kernel/time/BUILD
@@ -13,6 +13,7 @@ go_library(
     deps = [
         "//pkg/abi/linux",
         "//pkg/sentry/context",
+        "//pkg/sync",
         "//pkg/syserror",
         "//pkg/waiter",
     ],
diff --git a/pkg/sentry/kernel/time/time.go b/pkg/sentry/kernel/time/time.go
index 107394183..706de83ef 100644
--- a/pkg/sentry/kernel/time/time.go
+++ b/pkg/sentry/kernel/time/time.go
@@ -19,10 +19,10 @@ package time
 import (
 	"fmt"
 	"math"
-	"sync"
 	"time"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/kernel/timekeeper.go b/pkg/sentry/kernel/timekeeper.go
index 76417342a..dc99301de 100644
--- a/pkg/sentry/kernel/timekeeper.go
+++ b/pkg/sentry/kernel/timekeeper.go
@@ -16,7 +16,6 @@ package kernel
 
 import (
 	"fmt"
-	"sync"
 	"time"
 
 	"gvisor.dev/gvisor/pkg/log"
@@ -24,6 +23,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/pgalloc"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	sentrytime "gvisor.dev/gvisor/pkg/sentry/time"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // Timekeeper manages all of the kernel clocks.
diff --git a/pkg/sentry/kernel/tty.go b/pkg/sentry/kernel/tty.go
index 048de26dc..464d2306a 100644
--- a/pkg/sentry/kernel/tty.go
+++ b/pkg/sentry/kernel/tty.go
@@ -14,7 +14,7 @@
 
 package kernel
 
-import "sync"
+import "gvisor.dev/gvisor/pkg/sync"
 
 // TTY defines the relationship between a thread group and its controlling
 // terminal.
diff --git a/pkg/sentry/kernel/uts_namespace.go b/pkg/sentry/kernel/uts_namespace.go
index 0a563e715..8ccf04bd1 100644
--- a/pkg/sentry/kernel/uts_namespace.go
+++ b/pkg/sentry/kernel/uts_namespace.go
@@ -15,9 +15,8 @@
 package kernel
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // UTSNamespace represents a UTS namespace, a holder of two system identifiers:
diff --git a/pkg/sentry/limits/BUILD b/pkg/sentry/limits/BUILD
index 156e67bf8..9fa841e8b 100644
--- a/pkg/sentry/limits/BUILD
+++ b/pkg/sentry/limits/BUILD
@@ -15,6 +15,7 @@ go_library(
     deps = [
         "//pkg/abi/linux",
         "//pkg/sentry/context",
+        "//pkg/sync",
     ],
 )
 
diff --git a/pkg/sentry/limits/limits.go b/pkg/sentry/limits/limits.go
index b6c22656b..31b9e9ff6 100644
--- a/pkg/sentry/limits/limits.go
+++ b/pkg/sentry/limits/limits.go
@@ -16,8 +16,9 @@
 package limits
 
 import (
-	"sync"
 	"syscall"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // LimitType defines a type of resource limit.
diff --git a/pkg/sentry/mm/BUILD b/pkg/sentry/mm/BUILD
index 839931f67..83e248431 100644
--- a/pkg/sentry/mm/BUILD
+++ b/pkg/sentry/mm/BUILD
@@ -118,7 +118,7 @@ go_library(
         "//pkg/sentry/safemem",
         "//pkg/sentry/usage",
         "//pkg/sentry/usermem",
-        "//pkg/syncutil",
+        "//pkg/sync",
         "//pkg/syserror",
         "//pkg/tcpip/buffer",
     ],
diff --git a/pkg/sentry/mm/aio_context.go b/pkg/sentry/mm/aio_context.go
index 1b746d030..4b48866ad 100644
--- a/pkg/sentry/mm/aio_context.go
+++ b/pkg/sentry/mm/aio_context.go
@@ -15,8 +15,6 @@
 package mm
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/refs"
 	"gvisor.dev/gvisor/pkg/sentry/context"
@@ -25,6 +23,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/usage"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/mm/mm.go b/pkg/sentry/mm/mm.go
index 58a5c186d..fa86ebced 100644
--- a/pkg/sentry/mm/mm.go
+++ b/pkg/sentry/mm/mm.go
@@ -35,8 +35,6 @@
 package mm
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
@@ -44,7 +42,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
-	"gvisor.dev/gvisor/pkg/syncutil"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // MemoryManager implements a virtual address space.
@@ -82,7 +80,7 @@ type MemoryManager struct {
 	users int32
 
 	// mappingMu is analogous to Linux's struct mm_struct::mmap_sem.
-	mappingMu syncutil.DowngradableRWMutex `state:"nosave"`
+	mappingMu sync.DowngradableRWMutex `state:"nosave"`
 
 	// vmas stores virtual memory areas. Since vmas are stored by value,
 	// clients should usually use vmaIterator.ValuePtr() instead of
@@ -125,7 +123,7 @@ type MemoryManager struct {
 
 	// activeMu is loosely analogous to Linux's struct
 	// mm_struct::page_table_lock.
-	activeMu syncutil.DowngradableRWMutex `state:"nosave"`
+	activeMu sync.DowngradableRWMutex `state:"nosave"`
 
 	// pmas stores platform mapping areas used to implement vmas. Since pmas
 	// are stored by value, clients should usually use pmaIterator.ValuePtr()
diff --git a/pkg/sentry/pgalloc/BUILD b/pkg/sentry/pgalloc/BUILD
index f404107af..a9a2642c5 100644
--- a/pkg/sentry/pgalloc/BUILD
+++ b/pkg/sentry/pgalloc/BUILD
@@ -73,6 +73,7 @@ go_library(
         "//pkg/sentry/usage",
         "//pkg/sentry/usermem",
         "//pkg/state",
+        "//pkg/sync",
         "//pkg/syserror",
     ],
 )
diff --git a/pkg/sentry/pgalloc/pgalloc.go b/pkg/sentry/pgalloc/pgalloc.go
index f7f7298c4..c99e023d9 100644
--- a/pkg/sentry/pgalloc/pgalloc.go
+++ b/pkg/sentry/pgalloc/pgalloc.go
@@ -25,7 +25,6 @@ import (
 	"fmt"
 	"math"
 	"os"
-	"sync"
 	"sync/atomic"
 	"syscall"
 	"time"
@@ -37,6 +36,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/usage"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/platform/interrupt/BUILD b/pkg/sentry/platform/interrupt/BUILD
index b6d008dbe..85e882df9 100644
--- a/pkg/sentry/platform/interrupt/BUILD
+++ b/pkg/sentry/platform/interrupt/BUILD
@@ -10,6 +10,7 @@ go_library(
     ],
     importpath = "gvisor.dev/gvisor/pkg/sentry/platform/interrupt",
     visibility = ["//pkg/sentry:internal"],
+    deps = ["//pkg/sync"],
 )
 
 go_test(
diff --git a/pkg/sentry/platform/interrupt/interrupt.go b/pkg/sentry/platform/interrupt/interrupt.go
index a4651f500..57be41647 100644
--- a/pkg/sentry/platform/interrupt/interrupt.go
+++ b/pkg/sentry/platform/interrupt/interrupt.go
@@ -17,7 +17,8 @@ package interrupt
 
 import (
 	"fmt"
-	"sync"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // Receiver receives interrupt notifications from a Forwarder.
diff --git a/pkg/sentry/platform/kvm/BUILD b/pkg/sentry/platform/kvm/BUILD
index f3afd98da..6a358d1d4 100644
--- a/pkg/sentry/platform/kvm/BUILD
+++ b/pkg/sentry/platform/kvm/BUILD
@@ -55,6 +55,7 @@ go_library(
         "//pkg/sentry/platform/safecopy",
         "//pkg/sentry/time",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
     ],
 )
 
diff --git a/pkg/sentry/platform/kvm/address_space.go b/pkg/sentry/platform/kvm/address_space.go
index ea8b9632e..a25f3c449 100644
--- a/pkg/sentry/platform/kvm/address_space.go
+++ b/pkg/sentry/platform/kvm/address_space.go
@@ -15,13 +15,13 @@
 package kvm
 
 import (
-	"sync"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/atomicbitops"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // dirtySet tracks vCPUs for invalidation.
diff --git a/pkg/sentry/platform/kvm/bluepill_arm64_unsafe.go b/pkg/sentry/platform/kvm/bluepill_arm64_unsafe.go
index e5fac0d6a..2f02c03cf 100644
--- a/pkg/sentry/platform/kvm/bluepill_arm64_unsafe.go
+++ b/pkg/sentry/platform/kvm/bluepill_arm64_unsafe.go
@@ -17,8 +17,6 @@
 package kvm
 
 import (
-	"unsafe"
-
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 )
 
diff --git a/pkg/sentry/platform/kvm/kvm.go b/pkg/sentry/platform/kvm/kvm.go
index f2c2c059e..a7850faed 100644
--- a/pkg/sentry/platform/kvm/kvm.go
+++ b/pkg/sentry/platform/kvm/kvm.go
@@ -18,13 +18,13 @@ package kvm
 import (
 	"fmt"
 	"os"
-	"sync"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // KVM represents a lightweight VM context.
diff --git a/pkg/sentry/platform/kvm/machine.go b/pkg/sentry/platform/kvm/machine.go
index 7d02ebf19..e6d912168 100644
--- a/pkg/sentry/platform/kvm/machine.go
+++ b/pkg/sentry/platform/kvm/machine.go
@@ -17,7 +17,6 @@ package kvm
 import (
 	"fmt"
 	"runtime"
-	"sync"
 	"sync/atomic"
 	"syscall"
 
@@ -27,6 +26,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // machine contains state associated with the VM as a whole.
diff --git a/pkg/sentry/platform/ptrace/BUILD b/pkg/sentry/platform/ptrace/BUILD
index 0df8cfa0f..cd13390c3 100644
--- a/pkg/sentry/platform/ptrace/BUILD
+++ b/pkg/sentry/platform/ptrace/BUILD
@@ -33,6 +33,7 @@ go_library(
         "//pkg/sentry/platform/interrupt",
         "//pkg/sentry/platform/safecopy",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "@org_golang_x_sys//unix:go_default_library",
     ],
 )
diff --git a/pkg/sentry/platform/ptrace/ptrace.go b/pkg/sentry/platform/ptrace/ptrace.go
index 7b120a15d..bb0e03880 100644
--- a/pkg/sentry/platform/ptrace/ptrace.go
+++ b/pkg/sentry/platform/ptrace/ptrace.go
@@ -46,13 +46,13 @@ package ptrace
 
 import (
 	"os"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/platform/interrupt"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 var (
diff --git a/pkg/sentry/platform/ptrace/subprocess.go b/pkg/sentry/platform/ptrace/subprocess.go
index 20244fd95..15dc46a5b 100644
--- a/pkg/sentry/platform/ptrace/subprocess.go
+++ b/pkg/sentry/platform/ptrace/subprocess.go
@@ -18,7 +18,6 @@ import (
 	"fmt"
 	"os"
 	"runtime"
-	"sync"
 	"syscall"
 
 	"golang.org/x/sys/unix"
@@ -27,6 +26,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // Linux kernel errnos which "should never be seen by user programs", but will
diff --git a/pkg/sentry/platform/ptrace/subprocess_linux_unsafe.go b/pkg/sentry/platform/ptrace/subprocess_linux_unsafe.go
index 2e6fbe488..245b20722 100644
--- a/pkg/sentry/platform/ptrace/subprocess_linux_unsafe.go
+++ b/pkg/sentry/platform/ptrace/subprocess_linux_unsafe.go
@@ -18,7 +18,6 @@
 package ptrace
 
 import (
-	"sync"
 	"sync/atomic"
 	"syscall"
 	"unsafe"
@@ -26,6 +25,7 @@ import (
 	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/hostcpu"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // maskPool contains reusable CPU masks for setting affinity. Unfortunately,
diff --git a/pkg/sentry/platform/ring0/defs.go b/pkg/sentry/platform/ring0/defs.go
index 3f094c2a7..86fd5ed58 100644
--- a/pkg/sentry/platform/ring0/defs.go
+++ b/pkg/sentry/platform/ring0/defs.go
@@ -17,7 +17,7 @@ package ring0
 import (
 	"syscall"
 
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
 )
 
 // Kernel is a global kernel object.
diff --git a/pkg/sentry/platform/ring0/defs_amd64.go b/pkg/sentry/platform/ring0/defs_amd64.go
index 10dbd381f..9dae0dccb 100644
--- a/pkg/sentry/platform/ring0/defs_amd64.go
+++ b/pkg/sentry/platform/ring0/defs_amd64.go
@@ -18,6 +18,7 @@ package ring0
 
 import (
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
+	"gvisor.dev/gvisor/pkg/sentry/usermem"
 )
 
 var (
diff --git a/pkg/sentry/platform/ring0/defs_arm64.go b/pkg/sentry/platform/ring0/defs_arm64.go
index dc0eeec01..a850ce6cf 100644
--- a/pkg/sentry/platform/ring0/defs_arm64.go
+++ b/pkg/sentry/platform/ring0/defs_arm64.go
@@ -18,6 +18,7 @@ package ring0
 
 import (
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
+	"gvisor.dev/gvisor/pkg/sentry/usermem"
 )
 
 var (
diff --git a/pkg/sentry/platform/ring0/pagetables/BUILD b/pkg/sentry/platform/ring0/pagetables/BUILD
index e2e15ba5c..387a7f6c3 100644
--- a/pkg/sentry/platform/ring0/pagetables/BUILD
+++ b/pkg/sentry/platform/ring0/pagetables/BUILD
@@ -96,7 +96,10 @@ go_library(
         "//pkg/sentry/platform/kvm:__subpackages__",
         "//pkg/sentry/platform/ring0:__subpackages__",
     ],
-    deps = ["//pkg/sentry/usermem"],
+    deps = [
+        "//pkg/sentry/usermem",
+        "//pkg/sync",
+    ],
 )
 
 go_test(
diff --git a/pkg/sentry/platform/ring0/pagetables/pcids_x86.go b/pkg/sentry/platform/ring0/pagetables/pcids_x86.go
index 0f029f25d..e199bae18 100644
--- a/pkg/sentry/platform/ring0/pagetables/pcids_x86.go
+++ b/pkg/sentry/platform/ring0/pagetables/pcids_x86.go
@@ -17,7 +17,7 @@
 package pagetables
 
 import (
-	"sync"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // limitPCID is the number of valid PCIDs.
diff --git a/pkg/sentry/socket/netlink/BUILD b/pkg/sentry/socket/netlink/BUILD
index 136821963..103933144 100644
--- a/pkg/sentry/socket/netlink/BUILD
+++ b/pkg/sentry/socket/netlink/BUILD
@@ -27,6 +27,7 @@ go_library(
         "//pkg/sentry/socket/unix",
         "//pkg/sentry/socket/unix/transport",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserr",
         "//pkg/syserror",
         "//pkg/tcpip",
diff --git a/pkg/sentry/socket/netlink/port/BUILD b/pkg/sentry/socket/netlink/port/BUILD
index 463544c1a..2d9f4ba9b 100644
--- a/pkg/sentry/socket/netlink/port/BUILD
+++ b/pkg/sentry/socket/netlink/port/BUILD
@@ -8,6 +8,7 @@ go_library(
     srcs = ["port.go"],
     importpath = "gvisor.dev/gvisor/pkg/sentry/socket/netlink/port",
     visibility = ["//pkg/sentry:internal"],
+    deps = ["//pkg/sync"],
 )
 
 go_test(
diff --git a/pkg/sentry/socket/netlink/port/port.go b/pkg/sentry/socket/netlink/port/port.go
index e9d3275b1..2cd3afc22 100644
--- a/pkg/sentry/socket/netlink/port/port.go
+++ b/pkg/sentry/socket/netlink/port/port.go
@@ -24,7 +24,8 @@ import (
 	"fmt"
 	"math"
 	"math/rand"
-	"sync"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // maxPorts is a sanity limit on the maximum number of ports to allocate per
diff --git a/pkg/sentry/socket/netlink/socket.go b/pkg/sentry/socket/netlink/socket.go
index d2e3644a6..cea56f4ed 100644
--- a/pkg/sentry/socket/netlink/socket.go
+++ b/pkg/sentry/socket/netlink/socket.go
@@ -17,7 +17,6 @@ package netlink
 
 import (
 	"math"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/binary"
@@ -34,6 +33,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix"
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserr"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/tcpip"
diff --git a/pkg/sentry/socket/netstack/BUILD b/pkg/sentry/socket/netstack/BUILD
index e414d8055..f78784569 100644
--- a/pkg/sentry/socket/netstack/BUILD
+++ b/pkg/sentry/socket/netstack/BUILD
@@ -34,6 +34,7 @@ go_library(
         "//pkg/sentry/socket/netfilter",
         "//pkg/sentry/unimpl",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserr",
         "//pkg/syserror",
         "//pkg/tcpip",
diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go
index 764f11a6b..0affb8071 100644
--- a/pkg/sentry/socket/netstack/netstack.go
+++ b/pkg/sentry/socket/netstack/netstack.go
@@ -29,7 +29,6 @@ import (
 	"io"
 	"math"
 	"reflect"
-	"sync"
 	"syscall"
 	"time"
 
@@ -49,6 +48,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/socket/netfilter"
 	"gvisor.dev/gvisor/pkg/sentry/unimpl"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserr"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/tcpip"
diff --git a/pkg/sentry/socket/rpcinet/conn/BUILD b/pkg/sentry/socket/rpcinet/conn/BUILD
index 23eadcb1b..b2677c659 100644
--- a/pkg/sentry/socket/rpcinet/conn/BUILD
+++ b/pkg/sentry/socket/rpcinet/conn/BUILD
@@ -10,6 +10,7 @@ go_library(
     deps = [
         "//pkg/binary",
         "//pkg/sentry/socket/rpcinet:syscall_rpc_go_proto",
+        "//pkg/sync",
         "//pkg/syserr",
         "//pkg/unet",
         "@com_github_golang_protobuf//proto:go_default_library",
diff --git a/pkg/sentry/socket/rpcinet/conn/conn.go b/pkg/sentry/socket/rpcinet/conn/conn.go
index 356adad99..02f39c767 100644
--- a/pkg/sentry/socket/rpcinet/conn/conn.go
+++ b/pkg/sentry/socket/rpcinet/conn/conn.go
@@ -17,12 +17,12 @@ package conn
 
 import (
 	"fmt"
-	"sync"
 	"sync/atomic"
 	"syscall"
 
 	"github.com/golang/protobuf/proto"
 	"gvisor.dev/gvisor/pkg/binary"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserr"
 	"gvisor.dev/gvisor/pkg/unet"
 
diff --git a/pkg/sentry/socket/rpcinet/notifier/BUILD b/pkg/sentry/socket/rpcinet/notifier/BUILD
index a3585e10d..a5954f22b 100644
--- a/pkg/sentry/socket/rpcinet/notifier/BUILD
+++ b/pkg/sentry/socket/rpcinet/notifier/BUILD
@@ -10,6 +10,7 @@ go_library(
     deps = [
         "//pkg/sentry/socket/rpcinet:syscall_rpc_go_proto",
         "//pkg/sentry/socket/rpcinet/conn",
+        "//pkg/sync",
         "//pkg/waiter",
         "@org_golang_x_sys//unix:go_default_library",
     ],
diff --git a/pkg/sentry/socket/rpcinet/notifier/notifier.go b/pkg/sentry/socket/rpcinet/notifier/notifier.go
index 7efe4301f..82b75d6dd 100644
--- a/pkg/sentry/socket/rpcinet/notifier/notifier.go
+++ b/pkg/sentry/socket/rpcinet/notifier/notifier.go
@@ -17,12 +17,12 @@ package notifier
 
 import (
 	"fmt"
-	"sync"
 	"syscall"
 
 	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/sentry/socket/rpcinet/conn"
 	pb "gvisor.dev/gvisor/pkg/sentry/socket/rpcinet/syscall_rpc_go_proto"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
diff --git a/pkg/sentry/socket/unix/transport/BUILD b/pkg/sentry/socket/unix/transport/BUILD
index 788ad70d2..d7ba95dff 100644
--- a/pkg/sentry/socket/unix/transport/BUILD
+++ b/pkg/sentry/socket/unix/transport/BUILD
@@ -32,6 +32,7 @@ go_library(
         "//pkg/ilist",
         "//pkg/refs",
         "//pkg/sentry/context",
+        "//pkg/sync",
         "//pkg/syserr",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
diff --git a/pkg/sentry/socket/unix/transport/connectioned.go b/pkg/sentry/socket/unix/transport/connectioned.go
index dea11e253..9e6fbc111 100644
--- a/pkg/sentry/socket/unix/transport/connectioned.go
+++ b/pkg/sentry/socket/unix/transport/connectioned.go
@@ -15,10 +15,9 @@
 package transport
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserr"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/waiter"
diff --git a/pkg/sentry/socket/unix/transport/queue.go b/pkg/sentry/socket/unix/transport/queue.go
index e27b1c714..5dcd3d95e 100644
--- a/pkg/sentry/socket/unix/transport/queue.go
+++ b/pkg/sentry/socket/unix/transport/queue.go
@@ -15,9 +15,8 @@
 package transport
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/refs"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserr"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/socket/unix/transport/unix.go b/pkg/sentry/socket/unix/transport/unix.go
index 37c7ac3c1..fcc0da332 100644
--- a/pkg/sentry/socket/unix/transport/unix.go
+++ b/pkg/sentry/socket/unix/transport/unix.go
@@ -16,11 +16,11 @@
 package transport
 
 import (
-	"sync"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserr"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
diff --git a/pkg/sentry/syscalls/linux/BUILD b/pkg/sentry/syscalls/linux/BUILD
index a76975cee..aa05e208a 100644
--- a/pkg/sentry/syscalls/linux/BUILD
+++ b/pkg/sentry/syscalls/linux/BUILD
@@ -91,6 +91,7 @@ go_library(
         "//pkg/sentry/syscalls",
         "//pkg/sentry/usage",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserr",
         "//pkg/syserror",
         "//pkg/waiter",
diff --git a/pkg/sentry/syscalls/linux/error.go b/pkg/sentry/syscalls/linux/error.go
index 1d9018c96..60469549d 100644
--- a/pkg/sentry/syscalls/linux/error.go
+++ b/pkg/sentry/syscalls/linux/error.go
@@ -16,13 +16,13 @@ package linux
 
 import (
 	"io"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/metric"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/time/BUILD b/pkg/sentry/time/BUILD
index 18e212dff..3cde3a0be 100644
--- a/pkg/sentry/time/BUILD
+++ b/pkg/sentry/time/BUILD
@@ -9,7 +9,7 @@ go_template_instance(
     out = "seqatomic_parameters_unsafe.go",
     package = "time",
     suffix = "Parameters",
-    template = "//pkg/syncutil:generic_seqatomic",
+    template = "//pkg/sync:generic_seqatomic",
     types = {
         "Value": "Parameters",
     },
@@ -36,7 +36,7 @@ go_library(
     deps = [
         "//pkg/log",
         "//pkg/metric",
-        "//pkg/syncutil",
+        "//pkg/sync",
         "//pkg/syserror",
     ],
 )
diff --git a/pkg/sentry/time/calibrated_clock.go b/pkg/sentry/time/calibrated_clock.go
index 318503277..f9a93115d 100644
--- a/pkg/sentry/time/calibrated_clock.go
+++ b/pkg/sentry/time/calibrated_clock.go
@@ -17,11 +17,11 @@
 package time
 
 import (
-	"sync"
 	"time"
 
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/metric"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/usage/BUILD b/pkg/sentry/usage/BUILD
index c32fe3241..5518ac3d0 100644
--- a/pkg/sentry/usage/BUILD
+++ b/pkg/sentry/usage/BUILD
@@ -18,5 +18,6 @@ go_library(
     deps = [
         "//pkg/bits",
         "//pkg/memutil",
+        "//pkg/sync",
     ],
 )
diff --git a/pkg/sentry/usage/memory.go b/pkg/sentry/usage/memory.go
index d6ef644d8..538c645eb 100644
--- a/pkg/sentry/usage/memory.go
+++ b/pkg/sentry/usage/memory.go
@@ -17,12 +17,12 @@ package usage
 import (
 	"fmt"
 	"os"
-	"sync"
 	"sync/atomic"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/bits"
 	"gvisor.dev/gvisor/pkg/memutil"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // MemoryKind represents a type of memory used by the application.
diff --git a/pkg/sentry/vfs/BUILD b/pkg/sentry/vfs/BUILD
index 4c6aa04a1..35c7be259 100644
--- a/pkg/sentry/vfs/BUILD
+++ b/pkg/sentry/vfs/BUILD
@@ -34,7 +34,7 @@ go_library(
         "//pkg/sentry/kernel/auth",
         "//pkg/sentry/memmap",
         "//pkg/sentry/usermem",
-        "//pkg/syncutil",
+        "//pkg/sync",
         "//pkg/syserror",
         "//pkg/waiter",
     ],
@@ -54,6 +54,7 @@ go_test(
         "//pkg/sentry/context/contexttest",
         "//pkg/sentry/kernel/auth",
         "//pkg/sentry/usermem",
+        "//pkg/sync",
         "//pkg/syserror",
     ],
 )
diff --git a/pkg/sentry/vfs/dentry.go b/pkg/sentry/vfs/dentry.go
index 1bc9c4a38..486a76475 100644
--- a/pkg/sentry/vfs/dentry.go
+++ b/pkg/sentry/vfs/dentry.go
@@ -16,9 +16,9 @@ package vfs
 
 import (
 	"fmt"
-	"sync"
 	"sync/atomic"
 
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/vfs/file_description_impl_util.go b/pkg/sentry/vfs/file_description_impl_util.go
index 66eb57bc2..c00b3c84b 100644
--- a/pkg/sentry/vfs/file_description_impl_util.go
+++ b/pkg/sentry/vfs/file_description_impl_util.go
@@ -17,13 +17,13 @@ package vfs
 import (
 	"bytes"
 	"io"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
diff --git a/pkg/sentry/vfs/mount_test.go b/pkg/sentry/vfs/mount_test.go
index adff0b94b..3b933468d 100644
--- a/pkg/sentry/vfs/mount_test.go
+++ b/pkg/sentry/vfs/mount_test.go
@@ -17,8 +17,9 @@ package vfs
 import (
 	"fmt"
 	"runtime"
-	"sync"
 	"testing"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 func TestMountTableLookupEmpty(t *testing.T) {
diff --git a/pkg/sentry/vfs/mount_unsafe.go b/pkg/sentry/vfs/mount_unsafe.go
index ab13fa461..bd90d36c4 100644
--- a/pkg/sentry/vfs/mount_unsafe.go
+++ b/pkg/sentry/vfs/mount_unsafe.go
@@ -26,7 +26,7 @@ import (
 	"sync/atomic"
 	"unsafe"
 
-	"gvisor.dev/gvisor/pkg/syncutil"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // mountKey represents the location at which a Mount is mounted. It is
@@ -75,7 +75,7 @@ type mountTable struct {
 	// intrinsics and inline assembly, limiting the performance of this
 	// approach.)
 
-	seq  syncutil.SeqCount
+	seq  sync.SeqCount
 	seed uint32 // for hashing keys
 
 	// size holds both length (number of elements) and capacity (number of
diff --git a/pkg/sentry/vfs/pathname.go b/pkg/sentry/vfs/pathname.go
index 8e155654f..cf80df90e 100644
--- a/pkg/sentry/vfs/pathname.go
+++ b/pkg/sentry/vfs/pathname.go
@@ -15,10 +15,9 @@
 package vfs
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/fspath"
 	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/vfs/resolving_path.go b/pkg/sentry/vfs/resolving_path.go
index f0641d314..8a0b382f6 100644
--- a/pkg/sentry/vfs/resolving_path.go
+++ b/pkg/sentry/vfs/resolving_path.go
@@ -16,11 +16,11 @@ package vfs
 
 import (
 	"fmt"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/fspath"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/vfs/vfs.go b/pkg/sentry/vfs/vfs.go
index ea2db7031..1f21b0b31 100644
--- a/pkg/sentry/vfs/vfs.go
+++ b/pkg/sentry/vfs/vfs.go
@@ -29,12 +29,12 @@ package vfs
 
 import (
 	"fmt"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/fspath"
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
diff --git a/pkg/sentry/watchdog/BUILD b/pkg/sentry/watchdog/BUILD
index 4d8435265..28f21f13d 100644
--- a/pkg/sentry/watchdog/BUILD
+++ b/pkg/sentry/watchdog/BUILD
@@ -13,5 +13,6 @@ go_library(
         "//pkg/metric",
         "//pkg/sentry/kernel",
         "//pkg/sentry/kernel/time",
+        "//pkg/sync",
     ],
 )
diff --git a/pkg/sentry/watchdog/watchdog.go b/pkg/sentry/watchdog/watchdog.go
index 5e4611333..bfb2fac26 100644
--- a/pkg/sentry/watchdog/watchdog.go
+++ b/pkg/sentry/watchdog/watchdog.go
@@ -32,7 +32,6 @@ package watchdog
 import (
 	"bytes"
 	"fmt"
-	"sync"
 	"time"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
@@ -40,6 +39,7 @@ import (
 	"gvisor.dev/gvisor/pkg/metric"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // Opts configures the watchdog.
diff --git a/pkg/sync/BUILD b/pkg/sync/BUILD
new file mode 100644
index 000000000..e8cd16b8f
--- /dev/null
+++ b/pkg/sync/BUILD
@@ -0,0 +1,53 @@
+load("//tools/go_stateify:defs.bzl", "go_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_test")
+load("//tools/go_generics:defs.bzl", "go_template")
+
+package(
+    default_visibility = ["//:sandbox"],
+    licenses = ["notice"],
+)
+
+exports_files(["LICENSE"])
+
+go_template(
+    name = "generic_atomicptr",
+    srcs = ["atomicptr_unsafe.go"],
+    types = [
+        "Value",
+    ],
+)
+
+go_template(
+    name = "generic_seqatomic",
+    srcs = ["seqatomic_unsafe.go"],
+    types = [
+        "Value",
+    ],
+    deps = [
+        ":sync",
+    ],
+)
+
+go_library(
+    name = "sync",
+    srcs = [
+        "aliases.go",
+        "downgradable_rwmutex_unsafe.go",
+        "memmove_unsafe.go",
+        "norace_unsafe.go",
+        "race_unsafe.go",
+        "seqcount.go",
+        "syncutil.go",
+    ],
+    importpath = "gvisor.dev/gvisor/pkg/sync",
+)
+
+go_test(
+    name = "sync_test",
+    size = "small",
+    srcs = [
+        "downgradable_rwmutex_test.go",
+        "seqcount_test.go",
+    ],
+    embed = [":sync"],
+)
diff --git a/pkg/sync/LICENSE b/pkg/sync/LICENSE
new file mode 100644
index 000000000..6a66aea5e
--- /dev/null
+++ b/pkg/sync/LICENSE
@@ -0,0 +1,27 @@
+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/pkg/sync/README.md b/pkg/sync/README.md
new file mode 100644
index 000000000..2183c4e20
--- /dev/null
+++ b/pkg/sync/README.md
@@ -0,0 +1,5 @@
+# Syncutil
+
+This package provides additional synchronization primitives not provided by the
+Go stdlib 'sync' package. It is partially derived from the upstream 'sync'
+package from go1.10.
diff --git a/pkg/sync/aliases.go b/pkg/sync/aliases.go
new file mode 100644
index 000000000..20c7ca041
--- /dev/null
+++ b/pkg/sync/aliases.go
@@ -0,0 +1,37 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package sync
+
+import (
+	"sync"
+)
+
+// Aliases of standard library types.
+type (
+	// Mutex is an alias of sync.Mutex.
+	Mutex = sync.Mutex
+
+	// RWMutex is an alias of sync.RWMutex.
+	RWMutex = sync.RWMutex
+
+	// Cond is an alias of sync.Cond.
+	Cond = sync.Cond
+
+	// Locker is an alias of sync.Locker.
+	Locker = sync.Locker
+
+	// Once is an alias of sync.Once.
+	Once = sync.Once
+
+	// Pool is an alias of sync.Pool.
+	Pool = sync.Pool
+
+	// WaitGroup is an alias of sync.WaitGroup.
+	WaitGroup = sync.WaitGroup
+
+	// Map is an alias of sync.Map.
+	Map = sync.Map
+)
diff --git a/pkg/sync/atomicptr_unsafe.go b/pkg/sync/atomicptr_unsafe.go
new file mode 100644
index 000000000..525c4beed
--- /dev/null
+++ b/pkg/sync/atomicptr_unsafe.go
@@ -0,0 +1,47 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package template doesn't exist. This file must be instantiated using the
+// go_template_instance rule in tools/go_generics/defs.bzl.
+package template
+
+import (
+	"sync/atomic"
+	"unsafe"
+)
+
+// Value is a required type parameter.
+type Value struct{}
+
+// An AtomicPtr is a pointer to a value of type Value that can be atomically
+// loaded and stored. The zero value of an AtomicPtr represents nil.
+//
+// Note that copying AtomicPtr by value performs a non-atomic read of the
+// stored pointer, which is unsafe if Store() can be called concurrently; in
+// this case, do `dst.Store(src.Load())` instead.
+//
+// +stateify savable
+type AtomicPtr struct {
+	ptr unsafe.Pointer `state:".(*Value)"`
+}
+
+func (p *AtomicPtr) savePtr() *Value {
+	return p.Load()
+}
+
+func (p *AtomicPtr) loadPtr(v *Value) {
+	p.Store(v)
+}
+
+// Load returns the value set by the most recent Store. It returns nil if there
+// has been no previous call to Store.
+func (p *AtomicPtr) Load() *Value {
+	return (*Value)(atomic.LoadPointer(&p.ptr))
+}
+
+// Store sets the value returned by Load to x.
+func (p *AtomicPtr) Store(x *Value) {
+	atomic.StorePointer(&p.ptr, (unsafe.Pointer)(x))
+}
diff --git a/pkg/sync/atomicptrtest/BUILD b/pkg/sync/atomicptrtest/BUILD
new file mode 100644
index 000000000..418eda29c
--- /dev/null
+++ b/pkg/sync/atomicptrtest/BUILD
@@ -0,0 +1,29 @@
+load("//tools/go_stateify:defs.bzl", "go_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_test")
+load("//tools/go_generics:defs.bzl", "go_template_instance")
+
+package(licenses = ["notice"])
+
+go_template_instance(
+    name = "atomicptr_int",
+    out = "atomicptr_int_unsafe.go",
+    package = "atomicptr",
+    suffix = "Int",
+    template = "//pkg/sync:generic_atomicptr",
+    types = {
+        "Value": "int",
+    },
+)
+
+go_library(
+    name = "atomicptr",
+    srcs = ["atomicptr_int_unsafe.go"],
+    importpath = "gvisor.dev/gvisor/pkg/sync/atomicptr",
+)
+
+go_test(
+    name = "atomicptr_test",
+    size = "small",
+    srcs = ["atomicptr_test.go"],
+    embed = [":atomicptr"],
+)
diff --git a/pkg/sync/atomicptrtest/atomicptr_test.go b/pkg/sync/atomicptrtest/atomicptr_test.go
new file mode 100644
index 000000000..8fdc5112e
--- /dev/null
+++ b/pkg/sync/atomicptrtest/atomicptr_test.go
@@ -0,0 +1,31 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package atomicptr
+
+import (
+	"testing"
+)
+
+func newInt(val int) *int {
+	return &val
+}
+
+func TestAtomicPtr(t *testing.T) {
+	var p AtomicPtrInt
+	if got := p.Load(); got != nil {
+		t.Errorf("initial value is %p (%v), wanted nil", got, got)
+	}
+	want := newInt(42)
+	p.Store(want)
+	if got := p.Load(); got != want {
+		t.Errorf("wrong value: got %p (%v), wanted %p (%v)", got, got, want, want)
+	}
+	want = newInt(100)
+	p.Store(want)
+	if got := p.Load(); got != want {
+		t.Errorf("wrong value: got %p (%v), wanted %p (%v)", got, got, want, want)
+	}
+}
diff --git a/pkg/sync/downgradable_rwmutex_test.go b/pkg/sync/downgradable_rwmutex_test.go
new file mode 100644
index 000000000..f04496bc5
--- /dev/null
+++ b/pkg/sync/downgradable_rwmutex_test.go
@@ -0,0 +1,150 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Copyright 2019 The gVisor Authors.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// GOMAXPROCS=10 go test
+
+// Copy/pasted from the standard library's sync/rwmutex_test.go, except for the
+// addition of downgradingWriter and the renaming of num_iterations to
+// numIterations to shut up Golint.
+
+package sync
+
+import (
+	"fmt"
+	"runtime"
+	"sync/atomic"
+	"testing"
+)
+
+func parallelReader(m *DowngradableRWMutex, clocked, cunlock, cdone chan bool) {
+	m.RLock()
+	clocked <- true
+	<-cunlock
+	m.RUnlock()
+	cdone <- true
+}
+
+func doTestParallelReaders(numReaders, gomaxprocs int) {
+	runtime.GOMAXPROCS(gomaxprocs)
+	var m DowngradableRWMutex
+	clocked := make(chan bool)
+	cunlock := make(chan bool)
+	cdone := make(chan bool)
+	for i := 0; i < numReaders; i++ {
+		go parallelReader(&m, clocked, cunlock, cdone)
+	}
+	// Wait for all parallel RLock()s to succeed.
+	for i := 0; i < numReaders; i++ {
+		<-clocked
+	}
+	for i := 0; i < numReaders; i++ {
+		cunlock <- true
+	}
+	// Wait for the goroutines to finish.
+	for i := 0; i < numReaders; i++ {
+		<-cdone
+	}
+}
+
+func TestParallelReaders(t *testing.T) {
+	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(-1))
+	doTestParallelReaders(1, 4)
+	doTestParallelReaders(3, 4)
+	doTestParallelReaders(4, 2)
+}
+
+func reader(rwm *DowngradableRWMutex, numIterations int, activity *int32, cdone chan bool) {
+	for i := 0; i < numIterations; i++ {
+		rwm.RLock()
+		n := atomic.AddInt32(activity, 1)
+		if n < 1 || n >= 10000 {
+			panic(fmt.Sprintf("wlock(%d)\n", n))
+		}
+		for i := 0; i < 100; i++ {
+		}
+		atomic.AddInt32(activity, -1)
+		rwm.RUnlock()
+	}
+	cdone <- true
+}
+
+func writer(rwm *DowngradableRWMutex, numIterations int, activity *int32, cdone chan bool) {
+	for i := 0; i < numIterations; i++ {
+		rwm.Lock()
+		n := atomic.AddInt32(activity, 10000)
+		if n != 10000 {
+			panic(fmt.Sprintf("wlock(%d)\n", n))
+		}
+		for i := 0; i < 100; i++ {
+		}
+		atomic.AddInt32(activity, -10000)
+		rwm.Unlock()
+	}
+	cdone <- true
+}
+
+func downgradingWriter(rwm *DowngradableRWMutex, numIterations int, activity *int32, cdone chan bool) {
+	for i := 0; i < numIterations; i++ {
+		rwm.Lock()
+		n := atomic.AddInt32(activity, 10000)
+		if n != 10000 {
+			panic(fmt.Sprintf("wlock(%d)\n", n))
+		}
+		for i := 0; i < 100; i++ {
+		}
+		atomic.AddInt32(activity, -10000)
+		rwm.DowngradeLock()
+		n = atomic.AddInt32(activity, 1)
+		if n < 1 || n >= 10000 {
+			panic(fmt.Sprintf("wlock(%d)\n", n))
+		}
+		for i := 0; i < 100; i++ {
+		}
+		n = atomic.AddInt32(activity, -1)
+		rwm.RUnlock()
+	}
+	cdone <- true
+}
+
+func HammerDowngradableRWMutex(gomaxprocs, numReaders, numIterations int) {
+	runtime.GOMAXPROCS(gomaxprocs)
+	// Number of active readers + 10000 * number of active writers.
+	var activity int32
+	var rwm DowngradableRWMutex
+	cdone := make(chan bool)
+	go writer(&rwm, numIterations, &activity, cdone)
+	go downgradingWriter(&rwm, numIterations, &activity, cdone)
+	var i int
+	for i = 0; i < numReaders/2; i++ {
+		go reader(&rwm, numIterations, &activity, cdone)
+	}
+	go writer(&rwm, numIterations, &activity, cdone)
+	go downgradingWriter(&rwm, numIterations, &activity, cdone)
+	for ; i < numReaders; i++ {
+		go reader(&rwm, numIterations, &activity, cdone)
+	}
+	// Wait for the 4 writers and all readers to finish.
+	for i := 0; i < 4+numReaders; i++ {
+		<-cdone
+	}
+}
+
+func TestDowngradableRWMutex(t *testing.T) {
+	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(-1))
+	n := 1000
+	if testing.Short() {
+		n = 5
+	}
+	HammerDowngradableRWMutex(1, 1, n)
+	HammerDowngradableRWMutex(1, 3, n)
+	HammerDowngradableRWMutex(1, 10, n)
+	HammerDowngradableRWMutex(4, 1, n)
+	HammerDowngradableRWMutex(4, 3, n)
+	HammerDowngradableRWMutex(4, 10, n)
+	HammerDowngradableRWMutex(10, 1, n)
+	HammerDowngradableRWMutex(10, 3, n)
+	HammerDowngradableRWMutex(10, 10, n)
+	HammerDowngradableRWMutex(10, 5, n)
+}
diff --git a/pkg/sync/downgradable_rwmutex_unsafe.go b/pkg/sync/downgradable_rwmutex_unsafe.go
new file mode 100644
index 000000000..9bb55cd3a
--- /dev/null
+++ b/pkg/sync/downgradable_rwmutex_unsafe.go
@@ -0,0 +1,146 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Copyright 2019 The gVisor Authors.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.13
+// +build !go1.15
+
+// Check go:linkname function signatures when updating Go version.
+
+// This is mostly copied from the standard library's sync/rwmutex.go.
+//
+// Happens-before relationships indicated to the race detector:
+// - Unlock -> Lock (via writerSem)
+// - Unlock -> RLock (via readerSem)
+// - RUnlock -> Lock (via writerSem)
+// - DowngradeLock -> RLock (via readerSem)
+
+package sync
+
+import (
+	"sync"
+	"sync/atomic"
+	"unsafe"
+)
+
+//go:linkname runtimeSemacquire sync.runtime_Semacquire
+func runtimeSemacquire(s *uint32)
+
+//go:linkname runtimeSemrelease sync.runtime_Semrelease
+func runtimeSemrelease(s *uint32, handoff bool, skipframes int)
+
+// DowngradableRWMutex is identical to sync.RWMutex, but adds the DowngradeLock
+// method.
+type DowngradableRWMutex struct {
+	w           sync.Mutex // held if there are pending writers
+	writerSem   uint32     // semaphore for writers to wait for completing readers
+	readerSem   uint32     // semaphore for readers to wait for completing writers
+	readerCount int32      // number of pending readers
+	readerWait  int32      // number of departing readers
+}
+
+const rwmutexMaxReaders = 1 << 30
+
+// RLock locks rw for reading.
+func (rw *DowngradableRWMutex) RLock() {
+	if RaceEnabled {
+		RaceDisable()
+	}
+	if atomic.AddInt32(&rw.readerCount, 1) < 0 {
+		// A writer is pending, wait for it.
+		runtimeSemacquire(&rw.readerSem)
+	}
+	if RaceEnabled {
+		RaceEnable()
+		RaceAcquire(unsafe.Pointer(&rw.readerSem))
+	}
+}
+
+// RUnlock undoes a single RLock call.
+func (rw *DowngradableRWMutex) RUnlock() {
+	if RaceEnabled {
+		RaceReleaseMerge(unsafe.Pointer(&rw.writerSem))
+		RaceDisable()
+	}
+	if r := atomic.AddInt32(&rw.readerCount, -1); r < 0 {
+		if r+1 == 0 || r+1 == -rwmutexMaxReaders {
+			panic("RUnlock of unlocked DowngradableRWMutex")
+		}
+		// A writer is pending.
+		if atomic.AddInt32(&rw.readerWait, -1) == 0 {
+			// The last reader unblocks the writer.
+			runtimeSemrelease(&rw.writerSem, false, 0)
+		}
+	}
+	if RaceEnabled {
+		RaceEnable()
+	}
+}
+
+// Lock locks rw for writing.
+func (rw *DowngradableRWMutex) Lock() {
+	if RaceEnabled {
+		RaceDisable()
+	}
+	// First, resolve competition with other writers.
+	rw.w.Lock()
+	// Announce to readers there is a pending writer.
+	r := atomic.AddInt32(&rw.readerCount, -rwmutexMaxReaders) + rwmutexMaxReaders
+	// Wait for active readers.
+	if r != 0 && atomic.AddInt32(&rw.readerWait, r) != 0 {
+		runtimeSemacquire(&rw.writerSem)
+	}
+	if RaceEnabled {
+		RaceEnable()
+		RaceAcquire(unsafe.Pointer(&rw.writerSem))
+	}
+}
+
+// Unlock unlocks rw for writing.
+func (rw *DowngradableRWMutex) Unlock() {
+	if RaceEnabled {
+		RaceRelease(unsafe.Pointer(&rw.writerSem))
+		RaceRelease(unsafe.Pointer(&rw.readerSem))
+		RaceDisable()
+	}
+	// Announce to readers there is no active writer.
+	r := atomic.AddInt32(&rw.readerCount, rwmutexMaxReaders)
+	if r >= rwmutexMaxReaders {
+		panic("Unlock of unlocked DowngradableRWMutex")
+	}
+	// Unblock blocked readers, if any.
+	for i := 0; i < int(r); i++ {
+		runtimeSemrelease(&rw.readerSem, false, 0)
+	}
+	// Allow other writers to proceed.
+	rw.w.Unlock()
+	if RaceEnabled {
+		RaceEnable()
+	}
+}
+
+// DowngradeLock atomically unlocks rw for writing and locks it for reading.
+func (rw *DowngradableRWMutex) DowngradeLock() {
+	if RaceEnabled {
+		RaceRelease(unsafe.Pointer(&rw.readerSem))
+		RaceDisable()
+	}
+	// Announce to readers there is no active writer and one additional reader.
+	r := atomic.AddInt32(&rw.readerCount, rwmutexMaxReaders+1)
+	if r >= rwmutexMaxReaders+1 {
+		panic("DowngradeLock of unlocked DowngradableRWMutex")
+	}
+	// Unblock blocked readers, if any. Note that this loop starts as 1 since r
+	// includes this goroutine.
+	for i := 1; i < int(r); i++ {
+		runtimeSemrelease(&rw.readerSem, false, 0)
+	}
+	// Allow other writers to proceed to rw.w.Lock(). Note that they will still
+	// block on rw.writerSem since at least this reader exists, such that
+	// DowngradeLock() is atomic with the previous write lock.
+	rw.w.Unlock()
+	if RaceEnabled {
+		RaceEnable()
+	}
+}
diff --git a/pkg/sync/memmove_unsafe.go b/pkg/sync/memmove_unsafe.go
new file mode 100644
index 000000000..ad4a3a37e
--- /dev/null
+++ b/pkg/sync/memmove_unsafe.go
@@ -0,0 +1,28 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.12
+// +build !go1.15
+
+// Check go:linkname function signatures when updating Go version.
+
+package sync
+
+import (
+	"unsafe"
+)
+
+//go:linkname memmove runtime.memmove
+//go:noescape
+func memmove(to, from unsafe.Pointer, n uintptr)
+
+// Memmove is exported for SeqAtomicLoad/SeqAtomicTryLoad<T>, which can't
+// define it because go_generics can't update the go:linkname annotation.
+// Furthermore, go:linkname silently doesn't work if the local name is exported
+// (this is of course undocumented), which is why this indirection is
+// necessary.
+func Memmove(to, from unsafe.Pointer, n uintptr) {
+	memmove(to, from, n)
+}
diff --git a/pkg/sync/norace_unsafe.go b/pkg/sync/norace_unsafe.go
new file mode 100644
index 000000000..006055dd6
--- /dev/null
+++ b/pkg/sync/norace_unsafe.go
@@ -0,0 +1,35 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !race
+
+package sync
+
+import (
+	"unsafe"
+)
+
+// RaceEnabled is true if the Go data race detector is enabled.
+const RaceEnabled = false
+
+// RaceDisable has the same semantics as runtime.RaceDisable.
+func RaceDisable() {
+}
+
+// RaceEnable has the same semantics as runtime.RaceEnable.
+func RaceEnable() {
+}
+
+// RaceAcquire has the same semantics as runtime.RaceAcquire.
+func RaceAcquire(addr unsafe.Pointer) {
+}
+
+// RaceRelease has the same semantics as runtime.RaceRelease.
+func RaceRelease(addr unsafe.Pointer) {
+}
+
+// RaceReleaseMerge has the same semantics as runtime.RaceReleaseMerge.
+func RaceReleaseMerge(addr unsafe.Pointer) {
+}
diff --git a/pkg/sync/race_unsafe.go b/pkg/sync/race_unsafe.go
new file mode 100644
index 000000000..31d8fa9a6
--- /dev/null
+++ b/pkg/sync/race_unsafe.go
@@ -0,0 +1,41 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build race
+
+package sync
+
+import (
+	"runtime"
+	"unsafe"
+)
+
+// RaceEnabled is true if the Go data race detector is enabled.
+const RaceEnabled = true
+
+// RaceDisable has the same semantics as runtime.RaceDisable.
+func RaceDisable() {
+	runtime.RaceDisable()
+}
+
+// RaceEnable has the same semantics as runtime.RaceEnable.
+func RaceEnable() {
+	runtime.RaceEnable()
+}
+
+// RaceAcquire has the same semantics as runtime.RaceAcquire.
+func RaceAcquire(addr unsafe.Pointer) {
+	runtime.RaceAcquire(addr)
+}
+
+// RaceRelease has the same semantics as runtime.RaceRelease.
+func RaceRelease(addr unsafe.Pointer) {
+	runtime.RaceRelease(addr)
+}
+
+// RaceReleaseMerge has the same semantics as runtime.RaceReleaseMerge.
+func RaceReleaseMerge(addr unsafe.Pointer) {
+	runtime.RaceReleaseMerge(addr)
+}
diff --git a/pkg/sync/seqatomic_unsafe.go b/pkg/sync/seqatomic_unsafe.go
new file mode 100644
index 000000000..eda6fb131
--- /dev/null
+++ b/pkg/sync/seqatomic_unsafe.go
@@ -0,0 +1,72 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package template doesn't exist. This file must be instantiated using the
+// go_template_instance rule in tools/go_generics/defs.bzl.
+package template
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"unsafe"
+
+	"gvisor.dev/gvisor/pkg/sync"
+)
+
+// Value is a required type parameter.
+//
+// Value must not contain any pointers, including interface objects, function
+// objects, slices, maps, channels, unsafe.Pointer, and arrays or structs
+// containing any of the above. An init() function will panic if this property
+// does not hold.
+type Value struct{}
+
+// SeqAtomicLoad returns a copy of *ptr, ensuring that the read does not race
+// with any writer critical sections in sc.
+func SeqAtomicLoad(sc *sync.SeqCount, ptr *Value) Value {
+	// This function doesn't use SeqAtomicTryLoad because doing so is
+	// measurably, significantly (~20%) slower; Go is awful at inlining.
+	var val Value
+	for {
+		epoch := sc.BeginRead()
+		if sync.RaceEnabled {
+			// runtime.RaceDisable() doesn't actually stop the race detector,
+			// so it can't help us here. Instead, call runtime.memmove
+			// directly, which is not instrumented by the race detector.
+			sync.Memmove(unsafe.Pointer(&val), unsafe.Pointer(ptr), unsafe.Sizeof(val))
+		} else {
+			// This is ~40% faster for short reads than going through memmove.
+			val = *ptr
+		}
+		if sc.ReadOk(epoch) {
+			break
+		}
+	}
+	return val
+}
+
+// SeqAtomicTryLoad returns a copy of *ptr while in a reader critical section
+// in sc initiated by a call to sc.BeginRead() that returned epoch. If the read
+// would race with a writer critical section, SeqAtomicTryLoad returns
+// (unspecified, false).
+func SeqAtomicTryLoad(sc *sync.SeqCount, epoch sync.SeqCountEpoch, ptr *Value) (Value, bool) {
+	var val Value
+	if sync.RaceEnabled {
+		sync.Memmove(unsafe.Pointer(&val), unsafe.Pointer(ptr), unsafe.Sizeof(val))
+	} else {
+		val = *ptr
+	}
+	return val, sc.ReadOk(epoch)
+}
+
+func init() {
+	var val Value
+	typ := reflect.TypeOf(val)
+	name := typ.Name()
+	if ptrs := sync.PointersInType(typ, name); len(ptrs) != 0 {
+		panic(fmt.Sprintf("SeqAtomicLoad<%s> is invalid since values %s of type %s contain pointers:\n%s", typ, name, typ, strings.Join(ptrs, "\n")))
+	}
+}
diff --git a/pkg/sync/seqatomictest/BUILD b/pkg/sync/seqatomictest/BUILD
new file mode 100644
index 000000000..eba21518d
--- /dev/null
+++ b/pkg/sync/seqatomictest/BUILD
@@ -0,0 +1,33 @@
+load("//tools/go_stateify:defs.bzl", "go_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_test")
+load("//tools/go_generics:defs.bzl", "go_template_instance")
+
+package(licenses = ["notice"])
+
+go_template_instance(
+    name = "seqatomic_int",
+    out = "seqatomic_int_unsafe.go",
+    package = "seqatomic",
+    suffix = "Int",
+    template = "//pkg/sync:generic_seqatomic",
+    types = {
+        "Value": "int",
+    },
+)
+
+go_library(
+    name = "seqatomic",
+    srcs = ["seqatomic_int_unsafe.go"],
+    importpath = "gvisor.dev/gvisor/pkg/sync/seqatomic",
+    deps = [
+        "//pkg/sync",
+    ],
+)
+
+go_test(
+    name = "seqatomic_test",
+    size = "small",
+    srcs = ["seqatomic_test.go"],
+    embed = [":seqatomic"],
+    deps = ["//pkg/sync"],
+)
diff --git a/pkg/sync/seqatomictest/seqatomic_test.go b/pkg/sync/seqatomictest/seqatomic_test.go
new file mode 100644
index 000000000..2c4568b07
--- /dev/null
+++ b/pkg/sync/seqatomictest/seqatomic_test.go
@@ -0,0 +1,132 @@
+// Copyright 2018 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package seqatomic
+
+import (
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"gvisor.dev/gvisor/pkg/sync"
+)
+
+func TestSeqAtomicLoadUncontended(t *testing.T) {
+	var seq sync.SeqCount
+	const want = 1
+	data := want
+	if got := SeqAtomicLoadInt(&seq, &data); got != want {
+		t.Errorf("SeqAtomicLoadInt: got %v, wanted %v", got, want)
+	}
+}
+
+func TestSeqAtomicLoadAfterWrite(t *testing.T) {
+	var seq sync.SeqCount
+	var data int
+	const want = 1
+	seq.BeginWrite()
+	data = want
+	seq.EndWrite()
+	if got := SeqAtomicLoadInt(&seq, &data); got != want {
+		t.Errorf("SeqAtomicLoadInt: got %v, wanted %v", got, want)
+	}
+}
+
+func TestSeqAtomicLoadDuringWrite(t *testing.T) {
+	var seq sync.SeqCount
+	var data int
+	const want = 1
+	seq.BeginWrite()
+	go func() {
+		time.Sleep(time.Second)
+		data = want
+		seq.EndWrite()
+	}()
+	if got := SeqAtomicLoadInt(&seq, &data); got != want {
+		t.Errorf("SeqAtomicLoadInt: got %v, wanted %v", got, want)
+	}
+}
+
+func TestSeqAtomicTryLoadUncontended(t *testing.T) {
+	var seq sync.SeqCount
+	const want = 1
+	data := want
+	epoch := seq.BeginRead()
+	if got, ok := SeqAtomicTryLoadInt(&seq, epoch, &data); !ok || got != want {
+		t.Errorf("SeqAtomicTryLoadInt: got (%v, %v), wanted (%v, true)", got, ok, want)
+	}
+}
+
+func TestSeqAtomicTryLoadDuringWrite(t *testing.T) {
+	var seq sync.SeqCount
+	var data int
+	epoch := seq.BeginRead()
+	seq.BeginWrite()
+	if got, ok := SeqAtomicTryLoadInt(&seq, epoch, &data); ok {
+		t.Errorf("SeqAtomicTryLoadInt: got (%v, true), wanted (_, false)", got)
+	}
+	seq.EndWrite()
+}
+
+func TestSeqAtomicTryLoadAfterWrite(t *testing.T) {
+	var seq sync.SeqCount
+	var data int
+	epoch := seq.BeginRead()
+	seq.BeginWrite()
+	seq.EndWrite()
+	if got, ok := SeqAtomicTryLoadInt(&seq, epoch, &data); ok {
+		t.Errorf("SeqAtomicTryLoadInt: got (%v, true), wanted (_, false)", got)
+	}
+}
+
+func BenchmarkSeqAtomicLoadIntUncontended(b *testing.B) {
+	var seq sync.SeqCount
+	const want = 42
+	data := want
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			if got := SeqAtomicLoadInt(&seq, &data); got != want {
+				b.Fatalf("SeqAtomicLoadInt: got %v, wanted %v", got, want)
+			}
+		}
+	})
+}
+
+func BenchmarkSeqAtomicTryLoadIntUncontended(b *testing.B) {
+	var seq sync.SeqCount
+	const want = 42
+	data := want
+	b.RunParallel(func(pb *testing.PB) {
+		epoch := seq.BeginRead()
+		for pb.Next() {
+			if got, ok := SeqAtomicTryLoadInt(&seq, epoch, &data); !ok || got != want {
+				b.Fatalf("SeqAtomicTryLoadInt: got (%v, %v), wanted (%v, true)", got, ok, want)
+			}
+		}
+	})
+}
+
+// For comparison:
+func BenchmarkAtomicValueLoadIntUncontended(b *testing.B) {
+	var a atomic.Value
+	const want = 42
+	a.Store(int(want))
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			if got := a.Load().(int); got != want {
+				b.Fatalf("atomic.Value.Load: got %v, wanted %v", got, want)
+			}
+		}
+	})
+}
diff --git a/pkg/sync/seqcount.go b/pkg/sync/seqcount.go
new file mode 100644
index 000000000..a1e895352
--- /dev/null
+++ b/pkg/sync/seqcount.go
@@ -0,0 +1,149 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package sync
+
+import (
+	"fmt"
+	"reflect"
+	"runtime"
+	"sync/atomic"
+)
+
+// SeqCount is a synchronization primitive for optimistic reader/writer
+// synchronization in cases where readers can work with stale data and
+// therefore do not need to block writers.
+//
+// Compared to sync/atomic.Value:
+//
+// - Mutation of SeqCount-protected data does not require memory allocation,
+// whereas atomic.Value generally does. This is a significant advantage when
+// writes are common.
+//
+// - Atomic reads of SeqCount-protected data require copying. This is a
+// disadvantage when atomic reads are common.
+//
+// - SeqCount may be more flexible: correct use of SeqCount.ReadOk allows other
+// operations to be made atomic with reads of SeqCount-protected data.
+//
+// - SeqCount may be less flexible: as of this writing, SeqCount-protected data
+// cannot include pointers.
+//
+// - SeqCount is more cumbersome to use; atomic reads of SeqCount-protected
+// data require instantiating function templates using go_generics (see
+// seqatomic.go).
+type SeqCount struct {
+	// epoch is incremented by BeginWrite and EndWrite, such that epoch is odd
+	// if a writer critical section is active, and a read from data protected
+	// by this SeqCount is atomic iff epoch is the same even value before and
+	// after the read.
+	epoch uint32
+}
+
+// SeqCountEpoch tracks writer critical sections in a SeqCount.
+type SeqCountEpoch struct {
+	val uint32
+}
+
+// We assume that:
+//
+// - All functions in sync/atomic that perform a memory read are at least a
+// read fence: memory reads before calls to such functions cannot be reordered
+// after the call, and memory reads after calls to such functions cannot be
+// reordered before the call, even if those reads do not use sync/atomic.
+//
+// - All functions in sync/atomic that perform a memory write are at least a
+// write fence: memory writes before calls to such functions cannot be
+// reordered after the call, and memory writes after calls to such functions
+// cannot be reordered before the call, even if those writes do not use
+// sync/atomic.
+//
+// As of this writing, the Go memory model completely fails to describe
+// sync/atomic, but these properties are implied by
+// https://groups.google.com/forum/#!topic/golang-nuts/7EnEhM3U7B8.
+
+// BeginRead indicates the beginning of a reader critical section. Reader
+// critical sections DO NOT BLOCK writer critical sections, so operations in a
+// reader critical section MAY RACE with writer critical sections. Races are
+// detected by ReadOk at the end of the reader critical section. Thus, the
+// low-level structure of readers is generally:
+//
+//     for {
+//         epoch := seq.BeginRead()
+//         // do something idempotent with seq-protected data
+//         if seq.ReadOk(epoch) {
+//             break
+//         }
+//     }
+//
+// However, since reader critical sections may race with writer critical
+// sections, the Go race detector will (accurately) flag data races in readers
+// using this pattern. Most users of SeqCount will need to use the
+// SeqAtomicLoad function template in seqatomic.go.
+func (s *SeqCount) BeginRead() SeqCountEpoch {
+	epoch := atomic.LoadUint32(&s.epoch)
+	for epoch&1 != 0 {
+		runtime.Gosched()
+		epoch = atomic.LoadUint32(&s.epoch)
+	}
+	return SeqCountEpoch{epoch}
+}
+
+// ReadOk returns true if the reader critical section initiated by a previous
+// call to BeginRead() that returned epoch did not race with any writer critical
+// sections.
+//
+// ReadOk may be called any number of times during a reader critical section.
+// Reader critical sections do not need to be explicitly terminated; the last
+// call to ReadOk is implicitly the end of the reader critical section.
+func (s *SeqCount) ReadOk(epoch SeqCountEpoch) bool {
+	return atomic.LoadUint32(&s.epoch) == epoch.val
+}
+
+// BeginWrite indicates the beginning of a writer critical section.
+//
+// SeqCount does not support concurrent writer critical sections; clients with
+// concurrent writers must synchronize them using e.g. sync.Mutex.
+func (s *SeqCount) BeginWrite() {
+	if epoch := atomic.AddUint32(&s.epoch, 1); epoch&1 == 0 {
+		panic("SeqCount.BeginWrite during writer critical section")
+	}
+}
+
+// EndWrite ends the effect of a preceding BeginWrite.
+func (s *SeqCount) EndWrite() {
+	if epoch := atomic.AddUint32(&s.epoch, 1); epoch&1 != 0 {
+		panic("SeqCount.EndWrite outside writer critical section")
+	}
+}
+
+// PointersInType returns a list of pointers reachable from values named
+// valName of the given type.
+//
+// PointersInType is not exhaustive, but it is guaranteed that if typ contains
+// at least one pointer, then PointersInTypeOf returns a non-empty list.
+func PointersInType(typ reflect.Type, valName string) []string {
+	switch kind := typ.Kind(); kind {
+	case reflect.Bool, reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr, reflect.Float32, reflect.Float64, reflect.Complex64, reflect.Complex128:
+		return nil
+
+	case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice, reflect.String, reflect.UnsafePointer:
+		return []string{valName}
+
+	case reflect.Array:
+		return PointersInType(typ.Elem(), valName+"[]")
+
+	case reflect.Struct:
+		var ptrs []string
+		for i, n := 0, typ.NumField(); i < n; i++ {
+			field := typ.Field(i)
+			ptrs = append(ptrs, PointersInType(field.Type, fmt.Sprintf("%s.%s", valName, field.Name))...)
+		}
+		return ptrs
+
+	default:
+		return []string{fmt.Sprintf("%s (of type %s with unknown kind %s)", valName, typ, kind)}
+	}
+}
diff --git a/pkg/sync/seqcount_test.go b/pkg/sync/seqcount_test.go
new file mode 100644
index 000000000..6eb7b4b59
--- /dev/null
+++ b/pkg/sync/seqcount_test.go
@@ -0,0 +1,153 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package sync
+
+import (
+	"reflect"
+	"testing"
+	"time"
+)
+
+func TestSeqCountWriteUncontended(t *testing.T) {
+	var seq SeqCount
+	seq.BeginWrite()
+	seq.EndWrite()
+}
+
+func TestSeqCountReadUncontended(t *testing.T) {
+	var seq SeqCount
+	epoch := seq.BeginRead()
+	if !seq.ReadOk(epoch) {
+		t.Errorf("ReadOk: got false, wanted true")
+	}
+}
+
+func TestSeqCountBeginReadAfterWrite(t *testing.T) {
+	var seq SeqCount
+	var data int32
+	const want = 1
+	seq.BeginWrite()
+	data = want
+	seq.EndWrite()
+	epoch := seq.BeginRead()
+	if data != want {
+		t.Errorf("Reader: got %v, wanted %v", data, want)
+	}
+	if !seq.ReadOk(epoch) {
+		t.Errorf("ReadOk: got false, wanted true")
+	}
+}
+
+func TestSeqCountBeginReadDuringWrite(t *testing.T) {
+	var seq SeqCount
+	var data int
+	const want = 1
+	seq.BeginWrite()
+	go func() {
+		time.Sleep(time.Second)
+		data = want
+		seq.EndWrite()
+	}()
+	epoch := seq.BeginRead()
+	if data != want {
+		t.Errorf("Reader: got %v, wanted %v", data, want)
+	}
+	if !seq.ReadOk(epoch) {
+		t.Errorf("ReadOk: got false, wanted true")
+	}
+}
+
+func TestSeqCountReadOkAfterWrite(t *testing.T) {
+	var seq SeqCount
+	epoch := seq.BeginRead()
+	seq.BeginWrite()
+	seq.EndWrite()
+	if seq.ReadOk(epoch) {
+		t.Errorf("ReadOk: got true, wanted false")
+	}
+}
+
+func TestSeqCountReadOkDuringWrite(t *testing.T) {
+	var seq SeqCount
+	epoch := seq.BeginRead()
+	seq.BeginWrite()
+	if seq.ReadOk(epoch) {
+		t.Errorf("ReadOk: got true, wanted false")
+	}
+	seq.EndWrite()
+}
+
+func BenchmarkSeqCountWriteUncontended(b *testing.B) {
+	var seq SeqCount
+	for i := 0; i < b.N; i++ {
+		seq.BeginWrite()
+		seq.EndWrite()
+	}
+}
+
+func BenchmarkSeqCountReadUncontended(b *testing.B) {
+	var seq SeqCount
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			epoch := seq.BeginRead()
+			if !seq.ReadOk(epoch) {
+				b.Fatalf("ReadOk: got false, wanted true")
+			}
+		}
+	})
+}
+
+func TestPointersInType(t *testing.T) {
+	for _, test := range []struct {
+		name string // used for both test and value name
+		val  interface{}
+		ptrs []string
+	}{
+		{
+			name: "EmptyStruct",
+			val:  struct{}{},
+		},
+		{
+			name: "Int",
+			val:  int(0),
+		},
+		{
+			name: "MixedStruct",
+			val: struct {
+				b             bool
+				I             int
+				ExportedPtr   *struct{}
+				unexportedPtr *struct{}
+				arr           [2]int
+				ptrArr        [2]*int
+				nestedStruct  struct {
+					nestedNonptr int
+					nestedPtr    *int
+				}
+				structArr [1]struct {
+					nonptr int
+					ptr    *int
+				}
+			}{},
+			ptrs: []string{
+				"MixedStruct.ExportedPtr",
+				"MixedStruct.unexportedPtr",
+				"MixedStruct.ptrArr[]",
+				"MixedStruct.nestedStruct.nestedPtr",
+				"MixedStruct.structArr[].ptr",
+			},
+		},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			typ := reflect.TypeOf(test.val)
+			ptrs := PointersInType(typ, test.name)
+			t.Logf("Found pointers: %v", ptrs)
+			if (len(ptrs) != 0 || len(test.ptrs) != 0) && !reflect.DeepEqual(ptrs, test.ptrs) {
+				t.Errorf("Got %v, wanted %v", ptrs, test.ptrs)
+			}
+		})
+	}
+}
diff --git a/pkg/sync/syncutil.go b/pkg/sync/syncutil.go
new file mode 100644
index 000000000..b16cf5333
--- /dev/null
+++ b/pkg/sync/syncutil.go
@@ -0,0 +1,7 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package sync provides synchronization primitives.
+package sync
diff --git a/pkg/syncutil/BUILD b/pkg/syncutil/BUILD
deleted file mode 100644
index cb1f41628..000000000
--- a/pkg/syncutil/BUILD
+++ /dev/null
@@ -1,52 +0,0 @@
-load("//tools/go_stateify:defs.bzl", "go_library")
-load("@io_bazel_rules_go//go:def.bzl", "go_test")
-load("//tools/go_generics:defs.bzl", "go_template")
-
-package(
-    default_visibility = ["//:sandbox"],
-    licenses = ["notice"],
-)
-
-exports_files(["LICENSE"])
-
-go_template(
-    name = "generic_atomicptr",
-    srcs = ["atomicptr_unsafe.go"],
-    types = [
-        "Value",
-    ],
-)
-
-go_template(
-    name = "generic_seqatomic",
-    srcs = ["seqatomic_unsafe.go"],
-    types = [
-        "Value",
-    ],
-    deps = [
-        ":sync",
-    ],
-)
-
-go_library(
-    name = "syncutil",
-    srcs = [
-        "downgradable_rwmutex_unsafe.go",
-        "memmove_unsafe.go",
-        "norace_unsafe.go",
-        "race_unsafe.go",
-        "seqcount.go",
-        "syncutil.go",
-    ],
-    importpath = "gvisor.dev/gvisor/pkg/syncutil",
-)
-
-go_test(
-    name = "syncutil_test",
-    size = "small",
-    srcs = [
-        "downgradable_rwmutex_test.go",
-        "seqcount_test.go",
-    ],
-    embed = [":syncutil"],
-)
diff --git a/pkg/syncutil/LICENSE b/pkg/syncutil/LICENSE
deleted file mode 100644
index 6a66aea5e..000000000
--- a/pkg/syncutil/LICENSE
+++ /dev/null
@@ -1,27 +0,0 @@
-Copyright (c) 2009 The Go Authors. All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-   * Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above
-copyright notice, this list of conditions and the following disclaimer
-in the documentation and/or other materials provided with the
-distribution.
-   * Neither the name of Google Inc. nor the names of its
-contributors may be used to endorse or promote products derived from
-this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/pkg/syncutil/README.md b/pkg/syncutil/README.md
deleted file mode 100644
index 2183c4e20..000000000
--- a/pkg/syncutil/README.md
+++ /dev/null
@@ -1,5 +0,0 @@
-# Syncutil
-
-This package provides additional synchronization primitives not provided by the
-Go stdlib 'sync' package. It is partially derived from the upstream 'sync'
-package from go1.10.
diff --git a/pkg/syncutil/atomicptr_unsafe.go b/pkg/syncutil/atomicptr_unsafe.go
deleted file mode 100644
index 525c4beed..000000000
--- a/pkg/syncutil/atomicptr_unsafe.go
+++ /dev/null
@@ -1,47 +0,0 @@
-// Copyright 2019 The gVisor Authors.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package template doesn't exist. This file must be instantiated using the
-// go_template_instance rule in tools/go_generics/defs.bzl.
-package template
-
-import (
-	"sync/atomic"
-	"unsafe"
-)
-
-// Value is a required type parameter.
-type Value struct{}
-
-// An AtomicPtr is a pointer to a value of type Value that can be atomically
-// loaded and stored. The zero value of an AtomicPtr represents nil.
-//
-// Note that copying AtomicPtr by value performs a non-atomic read of the
-// stored pointer, which is unsafe if Store() can be called concurrently; in
-// this case, do `dst.Store(src.Load())` instead.
-//
-// +stateify savable
-type AtomicPtr struct {
-	ptr unsafe.Pointer `state:".(*Value)"`
-}
-
-func (p *AtomicPtr) savePtr() *Value {
-	return p.Load()
-}
-
-func (p *AtomicPtr) loadPtr(v *Value) {
-	p.Store(v)
-}
-
-// Load returns the value set by the most recent Store. It returns nil if there
-// has been no previous call to Store.
-func (p *AtomicPtr) Load() *Value {
-	return (*Value)(atomic.LoadPointer(&p.ptr))
-}
-
-// Store sets the value returned by Load to x.
-func (p *AtomicPtr) Store(x *Value) {
-	atomic.StorePointer(&p.ptr, (unsafe.Pointer)(x))
-}
diff --git a/pkg/syncutil/atomicptrtest/BUILD b/pkg/syncutil/atomicptrtest/BUILD
deleted file mode 100644
index 63f411a90..000000000
--- a/pkg/syncutil/atomicptrtest/BUILD
+++ /dev/null
@@ -1,29 +0,0 @@
-load("//tools/go_stateify:defs.bzl", "go_library")
-load("@io_bazel_rules_go//go:def.bzl", "go_test")
-load("//tools/go_generics:defs.bzl", "go_template_instance")
-
-package(licenses = ["notice"])
-
-go_template_instance(
-    name = "atomicptr_int",
-    out = "atomicptr_int_unsafe.go",
-    package = "atomicptr",
-    suffix = "Int",
-    template = "//pkg/syncutil:generic_atomicptr",
-    types = {
-        "Value": "int",
-    },
-)
-
-go_library(
-    name = "atomicptr",
-    srcs = ["atomicptr_int_unsafe.go"],
-    importpath = "gvisor.dev/gvisor/pkg/syncutil/atomicptr",
-)
-
-go_test(
-    name = "atomicptr_test",
-    size = "small",
-    srcs = ["atomicptr_test.go"],
-    embed = [":atomicptr"],
-)
diff --git a/pkg/syncutil/atomicptrtest/atomicptr_test.go b/pkg/syncutil/atomicptrtest/atomicptr_test.go
deleted file mode 100644
index 8fdc5112e..000000000
--- a/pkg/syncutil/atomicptrtest/atomicptr_test.go
+++ /dev/null
@@ -1,31 +0,0 @@
-// Copyright 2019 The gVisor Authors.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package atomicptr
-
-import (
-	"testing"
-)
-
-func newInt(val int) *int {
-	return &val
-}
-
-func TestAtomicPtr(t *testing.T) {
-	var p AtomicPtrInt
-	if got := p.Load(); got != nil {
-		t.Errorf("initial value is %p (%v), wanted nil", got, got)
-	}
-	want := newInt(42)
-	p.Store(want)
-	if got := p.Load(); got != want {
-		t.Errorf("wrong value: got %p (%v), wanted %p (%v)", got, got, want, want)
-	}
-	want = newInt(100)
-	p.Store(want)
-	if got := p.Load(); got != want {
-		t.Errorf("wrong value: got %p (%v), wanted %p (%v)", got, got, want, want)
-	}
-}
diff --git a/pkg/syncutil/downgradable_rwmutex_test.go b/pkg/syncutil/downgradable_rwmutex_test.go
deleted file mode 100644
index ffaf7ecc7..000000000
--- a/pkg/syncutil/downgradable_rwmutex_test.go
+++ /dev/null
@@ -1,150 +0,0 @@
-// Copyright 2009 The Go Authors. All rights reserved.
-// Copyright 2019 The gVisor Authors.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// GOMAXPROCS=10 go test
-
-// Copy/pasted from the standard library's sync/rwmutex_test.go, except for the
-// addition of downgradingWriter and the renaming of num_iterations to
-// numIterations to shut up Golint.
-
-package syncutil
-
-import (
-	"fmt"
-	"runtime"
-	"sync/atomic"
-	"testing"
-)
-
-func parallelReader(m *DowngradableRWMutex, clocked, cunlock, cdone chan bool) {
-	m.RLock()
-	clocked <- true
-	<-cunlock
-	m.RUnlock()
-	cdone <- true
-}
-
-func doTestParallelReaders(numReaders, gomaxprocs int) {
-	runtime.GOMAXPROCS(gomaxprocs)
-	var m DowngradableRWMutex
-	clocked := make(chan bool)
-	cunlock := make(chan bool)
-	cdone := make(chan bool)
-	for i := 0; i < numReaders; i++ {
-		go parallelReader(&m, clocked, cunlock, cdone)
-	}
-	// Wait for all parallel RLock()s to succeed.
-	for i := 0; i < numReaders; i++ {
-		<-clocked
-	}
-	for i := 0; i < numReaders; i++ {
-		cunlock <- true
-	}
-	// Wait for the goroutines to finish.
-	for i := 0; i < numReaders; i++ {
-		<-cdone
-	}
-}
-
-func TestParallelReaders(t *testing.T) {
-	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(-1))
-	doTestParallelReaders(1, 4)
-	doTestParallelReaders(3, 4)
-	doTestParallelReaders(4, 2)
-}
-
-func reader(rwm *DowngradableRWMutex, numIterations int, activity *int32, cdone chan bool) {
-	for i := 0; i < numIterations; i++ {
-		rwm.RLock()
-		n := atomic.AddInt32(activity, 1)
-		if n < 1 || n >= 10000 {
-			panic(fmt.Sprintf("wlock(%d)\n", n))
-		}
-		for i := 0; i < 100; i++ {
-		}
-		atomic.AddInt32(activity, -1)
-		rwm.RUnlock()
-	}
-	cdone <- true
-}
-
-func writer(rwm *DowngradableRWMutex, numIterations int, activity *int32, cdone chan bool) {
-	for i := 0; i < numIterations; i++ {
-		rwm.Lock()
-		n := atomic.AddInt32(activity, 10000)
-		if n != 10000 {
-			panic(fmt.Sprintf("wlock(%d)\n", n))
-		}
-		for i := 0; i < 100; i++ {
-		}
-		atomic.AddInt32(activity, -10000)
-		rwm.Unlock()
-	}
-	cdone <- true
-}
-
-func downgradingWriter(rwm *DowngradableRWMutex, numIterations int, activity *int32, cdone chan bool) {
-	for i := 0; i < numIterations; i++ {
-		rwm.Lock()
-		n := atomic.AddInt32(activity, 10000)
-		if n != 10000 {
-			panic(fmt.Sprintf("wlock(%d)\n", n))
-		}
-		for i := 0; i < 100; i++ {
-		}
-		atomic.AddInt32(activity, -10000)
-		rwm.DowngradeLock()
-		n = atomic.AddInt32(activity, 1)
-		if n < 1 || n >= 10000 {
-			panic(fmt.Sprintf("wlock(%d)\n", n))
-		}
-		for i := 0; i < 100; i++ {
-		}
-		n = atomic.AddInt32(activity, -1)
-		rwm.RUnlock()
-	}
-	cdone <- true
-}
-
-func HammerDowngradableRWMutex(gomaxprocs, numReaders, numIterations int) {
-	runtime.GOMAXPROCS(gomaxprocs)
-	// Number of active readers + 10000 * number of active writers.
-	var activity int32
-	var rwm DowngradableRWMutex
-	cdone := make(chan bool)
-	go writer(&rwm, numIterations, &activity, cdone)
-	go downgradingWriter(&rwm, numIterations, &activity, cdone)
-	var i int
-	for i = 0; i < numReaders/2; i++ {
-		go reader(&rwm, numIterations, &activity, cdone)
-	}
-	go writer(&rwm, numIterations, &activity, cdone)
-	go downgradingWriter(&rwm, numIterations, &activity, cdone)
-	for ; i < numReaders; i++ {
-		go reader(&rwm, numIterations, &activity, cdone)
-	}
-	// Wait for the 4 writers and all readers to finish.
-	for i := 0; i < 4+numReaders; i++ {
-		<-cdone
-	}
-}
-
-func TestDowngradableRWMutex(t *testing.T) {
-	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(-1))
-	n := 1000
-	if testing.Short() {
-		n = 5
-	}
-	HammerDowngradableRWMutex(1, 1, n)
-	HammerDowngradableRWMutex(1, 3, n)
-	HammerDowngradableRWMutex(1, 10, n)
-	HammerDowngradableRWMutex(4, 1, n)
-	HammerDowngradableRWMutex(4, 3, n)
-	HammerDowngradableRWMutex(4, 10, n)
-	HammerDowngradableRWMutex(10, 1, n)
-	HammerDowngradableRWMutex(10, 3, n)
-	HammerDowngradableRWMutex(10, 10, n)
-	HammerDowngradableRWMutex(10, 5, n)
-}
diff --git a/pkg/syncutil/downgradable_rwmutex_unsafe.go b/pkg/syncutil/downgradable_rwmutex_unsafe.go
deleted file mode 100644
index 51e11555d..000000000
--- a/pkg/syncutil/downgradable_rwmutex_unsafe.go
+++ /dev/null
@@ -1,146 +0,0 @@
-// Copyright 2009 The Go Authors. All rights reserved.
-// Copyright 2019 The gVisor Authors.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build go1.13
-// +build !go1.15
-
-// Check go:linkname function signatures when updating Go version.
-
-// This is mostly copied from the standard library's sync/rwmutex.go.
-//
-// Happens-before relationships indicated to the race detector:
-// - Unlock -> Lock (via writerSem)
-// - Unlock -> RLock (via readerSem)
-// - RUnlock -> Lock (via writerSem)
-// - DowngradeLock -> RLock (via readerSem)
-
-package syncutil
-
-import (
-	"sync"
-	"sync/atomic"
-	"unsafe"
-)
-
-//go:linkname runtimeSemacquire sync.runtime_Semacquire
-func runtimeSemacquire(s *uint32)
-
-//go:linkname runtimeSemrelease sync.runtime_Semrelease
-func runtimeSemrelease(s *uint32, handoff bool, skipframes int)
-
-// DowngradableRWMutex is identical to sync.RWMutex, but adds the DowngradeLock
-// method.
-type DowngradableRWMutex struct {
-	w           sync.Mutex // held if there are pending writers
-	writerSem   uint32     // semaphore for writers to wait for completing readers
-	readerSem   uint32     // semaphore for readers to wait for completing writers
-	readerCount int32      // number of pending readers
-	readerWait  int32      // number of departing readers
-}
-
-const rwmutexMaxReaders = 1 << 30
-
-// RLock locks rw for reading.
-func (rw *DowngradableRWMutex) RLock() {
-	if RaceEnabled {
-		RaceDisable()
-	}
-	if atomic.AddInt32(&rw.readerCount, 1) < 0 {
-		// A writer is pending, wait for it.
-		runtimeSemacquire(&rw.readerSem)
-	}
-	if RaceEnabled {
-		RaceEnable()
-		RaceAcquire(unsafe.Pointer(&rw.readerSem))
-	}
-}
-
-// RUnlock undoes a single RLock call.
-func (rw *DowngradableRWMutex) RUnlock() {
-	if RaceEnabled {
-		RaceReleaseMerge(unsafe.Pointer(&rw.writerSem))
-		RaceDisable()
-	}
-	if r := atomic.AddInt32(&rw.readerCount, -1); r < 0 {
-		if r+1 == 0 || r+1 == -rwmutexMaxReaders {
-			panic("RUnlock of unlocked DowngradableRWMutex")
-		}
-		// A writer is pending.
-		if atomic.AddInt32(&rw.readerWait, -1) == 0 {
-			// The last reader unblocks the writer.
-			runtimeSemrelease(&rw.writerSem, false, 0)
-		}
-	}
-	if RaceEnabled {
-		RaceEnable()
-	}
-}
-
-// Lock locks rw for writing.
-func (rw *DowngradableRWMutex) Lock() {
-	if RaceEnabled {
-		RaceDisable()
-	}
-	// First, resolve competition with other writers.
-	rw.w.Lock()
-	// Announce to readers there is a pending writer.
-	r := atomic.AddInt32(&rw.readerCount, -rwmutexMaxReaders) + rwmutexMaxReaders
-	// Wait for active readers.
-	if r != 0 && atomic.AddInt32(&rw.readerWait, r) != 0 {
-		runtimeSemacquire(&rw.writerSem)
-	}
-	if RaceEnabled {
-		RaceEnable()
-		RaceAcquire(unsafe.Pointer(&rw.writerSem))
-	}
-}
-
-// Unlock unlocks rw for writing.
-func (rw *DowngradableRWMutex) Unlock() {
-	if RaceEnabled {
-		RaceRelease(unsafe.Pointer(&rw.writerSem))
-		RaceRelease(unsafe.Pointer(&rw.readerSem))
-		RaceDisable()
-	}
-	// Announce to readers there is no active writer.
-	r := atomic.AddInt32(&rw.readerCount, rwmutexMaxReaders)
-	if r >= rwmutexMaxReaders {
-		panic("Unlock of unlocked DowngradableRWMutex")
-	}
-	// Unblock blocked readers, if any.
-	for i := 0; i < int(r); i++ {
-		runtimeSemrelease(&rw.readerSem, false, 0)
-	}
-	// Allow other writers to proceed.
-	rw.w.Unlock()
-	if RaceEnabled {
-		RaceEnable()
-	}
-}
-
-// DowngradeLock atomically unlocks rw for writing and locks it for reading.
-func (rw *DowngradableRWMutex) DowngradeLock() {
-	if RaceEnabled {
-		RaceRelease(unsafe.Pointer(&rw.readerSem))
-		RaceDisable()
-	}
-	// Announce to readers there is no active writer and one additional reader.
-	r := atomic.AddInt32(&rw.readerCount, rwmutexMaxReaders+1)
-	if r >= rwmutexMaxReaders+1 {
-		panic("DowngradeLock of unlocked DowngradableRWMutex")
-	}
-	// Unblock blocked readers, if any. Note that this loop starts as 1 since r
-	// includes this goroutine.
-	for i := 1; i < int(r); i++ {
-		runtimeSemrelease(&rw.readerSem, false, 0)
-	}
-	// Allow other writers to proceed to rw.w.Lock(). Note that they will still
-	// block on rw.writerSem since at least this reader exists, such that
-	// DowngradeLock() is atomic with the previous write lock.
-	rw.w.Unlock()
-	if RaceEnabled {
-		RaceEnable()
-	}
-}
diff --git a/pkg/syncutil/memmove_unsafe.go b/pkg/syncutil/memmove_unsafe.go
deleted file mode 100644
index 348675baa..000000000
--- a/pkg/syncutil/memmove_unsafe.go
+++ /dev/null
@@ -1,28 +0,0 @@
-// Copyright 2019 The gVisor Authors.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build go1.12
-// +build !go1.15
-
-// Check go:linkname function signatures when updating Go version.
-
-package syncutil
-
-import (
-	"unsafe"
-)
-
-//go:linkname memmove runtime.memmove
-//go:noescape
-func memmove(to, from unsafe.Pointer, n uintptr)
-
-// Memmove is exported for SeqAtomicLoad/SeqAtomicTryLoad<T>, which can't
-// define it because go_generics can't update the go:linkname annotation.
-// Furthermore, go:linkname silently doesn't work if the local name is exported
-// (this is of course undocumented), which is why this indirection is
-// necessary.
-func Memmove(to, from unsafe.Pointer, n uintptr) {
-	memmove(to, from, n)
-}
diff --git a/pkg/syncutil/norace_unsafe.go b/pkg/syncutil/norace_unsafe.go
deleted file mode 100644
index 0a0a9deda..000000000
--- a/pkg/syncutil/norace_unsafe.go
+++ /dev/null
@@ -1,35 +0,0 @@
-// Copyright 2019 The gVisor Authors.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build !race
-
-package syncutil
-
-import (
-	"unsafe"
-)
-
-// RaceEnabled is true if the Go data race detector is enabled.
-const RaceEnabled = false
-
-// RaceDisable has the same semantics as runtime.RaceDisable.
-func RaceDisable() {
-}
-
-// RaceEnable has the same semantics as runtime.RaceEnable.
-func RaceEnable() {
-}
-
-// RaceAcquire has the same semantics as runtime.RaceAcquire.
-func RaceAcquire(addr unsafe.Pointer) {
-}
-
-// RaceRelease has the same semantics as runtime.RaceRelease.
-func RaceRelease(addr unsafe.Pointer) {
-}
-
-// RaceReleaseMerge has the same semantics as runtime.RaceReleaseMerge.
-func RaceReleaseMerge(addr unsafe.Pointer) {
-}
diff --git a/pkg/syncutil/race_unsafe.go b/pkg/syncutil/race_unsafe.go
deleted file mode 100644
index 206067ec1..000000000
--- a/pkg/syncutil/race_unsafe.go
+++ /dev/null
@@ -1,41 +0,0 @@
-// Copyright 2019 The gVisor Authors.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build race
-
-package syncutil
-
-import (
-	"runtime"
-	"unsafe"
-)
-
-// RaceEnabled is true if the Go data race detector is enabled.
-const RaceEnabled = true
-
-// RaceDisable has the same semantics as runtime.RaceDisable.
-func RaceDisable() {
-	runtime.RaceDisable()
-}
-
-// RaceEnable has the same semantics as runtime.RaceEnable.
-func RaceEnable() {
-	runtime.RaceEnable()
-}
-
-// RaceAcquire has the same semantics as runtime.RaceAcquire.
-func RaceAcquire(addr unsafe.Pointer) {
-	runtime.RaceAcquire(addr)
-}
-
-// RaceRelease has the same semantics as runtime.RaceRelease.
-func RaceRelease(addr unsafe.Pointer) {
-	runtime.RaceRelease(addr)
-}
-
-// RaceReleaseMerge has the same semantics as runtime.RaceReleaseMerge.
-func RaceReleaseMerge(addr unsafe.Pointer) {
-	runtime.RaceReleaseMerge(addr)
-}
diff --git a/pkg/syncutil/seqatomic_unsafe.go b/pkg/syncutil/seqatomic_unsafe.go
deleted file mode 100644
index cb6d2eb22..000000000
--- a/pkg/syncutil/seqatomic_unsafe.go
+++ /dev/null
@@ -1,72 +0,0 @@
-// Copyright 2019 The gVisor Authors.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package template doesn't exist. This file must be instantiated using the
-// go_template_instance rule in tools/go_generics/defs.bzl.
-package template
-
-import (
-	"fmt"
-	"reflect"
-	"strings"
-	"unsafe"
-
-	"gvisor.dev/gvisor/pkg/syncutil"
-)
-
-// Value is a required type parameter.
-//
-// Value must not contain any pointers, including interface objects, function
-// objects, slices, maps, channels, unsafe.Pointer, and arrays or structs
-// containing any of the above. An init() function will panic if this property
-// does not hold.
-type Value struct{}
-
-// SeqAtomicLoad returns a copy of *ptr, ensuring that the read does not race
-// with any writer critical sections in sc.
-func SeqAtomicLoad(sc *syncutil.SeqCount, ptr *Value) Value {
-	// This function doesn't use SeqAtomicTryLoad because doing so is
-	// measurably, significantly (~20%) slower; Go is awful at inlining.
-	var val Value
-	for {
-		epoch := sc.BeginRead()
-		if syncutil.RaceEnabled {
-			// runtime.RaceDisable() doesn't actually stop the race detector,
-			// so it can't help us here. Instead, call runtime.memmove
-			// directly, which is not instrumented by the race detector.
-			syncutil.Memmove(unsafe.Pointer(&val), unsafe.Pointer(ptr), unsafe.Sizeof(val))
-		} else {
-			// This is ~40% faster for short reads than going through memmove.
-			val = *ptr
-		}
-		if sc.ReadOk(epoch) {
-			break
-		}
-	}
-	return val
-}
-
-// SeqAtomicTryLoad returns a copy of *ptr while in a reader critical section
-// in sc initiated by a call to sc.BeginRead() that returned epoch. If the read
-// would race with a writer critical section, SeqAtomicTryLoad returns
-// (unspecified, false).
-func SeqAtomicTryLoad(sc *syncutil.SeqCount, epoch syncutil.SeqCountEpoch, ptr *Value) (Value, bool) {
-	var val Value
-	if syncutil.RaceEnabled {
-		syncutil.Memmove(unsafe.Pointer(&val), unsafe.Pointer(ptr), unsafe.Sizeof(val))
-	} else {
-		val = *ptr
-	}
-	return val, sc.ReadOk(epoch)
-}
-
-func init() {
-	var val Value
-	typ := reflect.TypeOf(val)
-	name := typ.Name()
-	if ptrs := syncutil.PointersInType(typ, name); len(ptrs) != 0 {
-		panic(fmt.Sprintf("SeqAtomicLoad<%s> is invalid since values %s of type %s contain pointers:\n%s", typ, name, typ, strings.Join(ptrs, "\n")))
-	}
-}
diff --git a/pkg/syncutil/seqatomictest/BUILD b/pkg/syncutil/seqatomictest/BUILD
deleted file mode 100644
index ba18f3238..000000000
--- a/pkg/syncutil/seqatomictest/BUILD
+++ /dev/null
@@ -1,35 +0,0 @@
-load("//tools/go_stateify:defs.bzl", "go_library")
-load("@io_bazel_rules_go//go:def.bzl", "go_test")
-load("//tools/go_generics:defs.bzl", "go_template_instance")
-
-package(licenses = ["notice"])
-
-go_template_instance(
-    name = "seqatomic_int",
-    out = "seqatomic_int_unsafe.go",
-    package = "seqatomic",
-    suffix = "Int",
-    template = "//pkg/syncutil:generic_seqatomic",
-    types = {
-        "Value": "int",
-    },
-)
-
-go_library(
-    name = "seqatomic",
-    srcs = ["seqatomic_int_unsafe.go"],
-    importpath = "gvisor.dev/gvisor/pkg/syncutil/seqatomic",
-    deps = [
-        "//pkg/syncutil",
-    ],
-)
-
-go_test(
-    name = "seqatomic_test",
-    size = "small",
-    srcs = ["seqatomic_test.go"],
-    embed = [":seqatomic"],
-    deps = [
-        "//pkg/syncutil",
-    ],
-)
diff --git a/pkg/syncutil/seqatomictest/seqatomic_test.go b/pkg/syncutil/seqatomictest/seqatomic_test.go
deleted file mode 100644
index b0db44999..000000000
--- a/pkg/syncutil/seqatomictest/seqatomic_test.go
+++ /dev/null
@@ -1,132 +0,0 @@
-// Copyright 2018 The gVisor Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package seqatomic
-
-import (
-	"sync/atomic"
-	"testing"
-	"time"
-
-	"gvisor.dev/gvisor/pkg/syncutil"
-)
-
-func TestSeqAtomicLoadUncontended(t *testing.T) {
-	var seq syncutil.SeqCount
-	const want = 1
-	data := want
-	if got := SeqAtomicLoadInt(&seq, &data); got != want {
-		t.Errorf("SeqAtomicLoadInt: got %v, wanted %v", got, want)
-	}
-}
-
-func TestSeqAtomicLoadAfterWrite(t *testing.T) {
-	var seq syncutil.SeqCount
-	var data int
-	const want = 1
-	seq.BeginWrite()
-	data = want
-	seq.EndWrite()
-	if got := SeqAtomicLoadInt(&seq, &data); got != want {
-		t.Errorf("SeqAtomicLoadInt: got %v, wanted %v", got, want)
-	}
-}
-
-func TestSeqAtomicLoadDuringWrite(t *testing.T) {
-	var seq syncutil.SeqCount
-	var data int
-	const want = 1
-	seq.BeginWrite()
-	go func() {
-		time.Sleep(time.Second)
-		data = want
-		seq.EndWrite()
-	}()
-	if got := SeqAtomicLoadInt(&seq, &data); got != want {
-		t.Errorf("SeqAtomicLoadInt: got %v, wanted %v", got, want)
-	}
-}
-
-func TestSeqAtomicTryLoadUncontended(t *testing.T) {
-	var seq syncutil.SeqCount
-	const want = 1
-	data := want
-	epoch := seq.BeginRead()
-	if got, ok := SeqAtomicTryLoadInt(&seq, epoch, &data); !ok || got != want {
-		t.Errorf("SeqAtomicTryLoadInt: got (%v, %v), wanted (%v, true)", got, ok, want)
-	}
-}
-
-func TestSeqAtomicTryLoadDuringWrite(t *testing.T) {
-	var seq syncutil.SeqCount
-	var data int
-	epoch := seq.BeginRead()
-	seq.BeginWrite()
-	if got, ok := SeqAtomicTryLoadInt(&seq, epoch, &data); ok {
-		t.Errorf("SeqAtomicTryLoadInt: got (%v, true), wanted (_, false)", got)
-	}
-	seq.EndWrite()
-}
-
-func TestSeqAtomicTryLoadAfterWrite(t *testing.T) {
-	var seq syncutil.SeqCount
-	var data int
-	epoch := seq.BeginRead()
-	seq.BeginWrite()
-	seq.EndWrite()
-	if got, ok := SeqAtomicTryLoadInt(&seq, epoch, &data); ok {
-		t.Errorf("SeqAtomicTryLoadInt: got (%v, true), wanted (_, false)", got)
-	}
-}
-
-func BenchmarkSeqAtomicLoadIntUncontended(b *testing.B) {
-	var seq syncutil.SeqCount
-	const want = 42
-	data := want
-	b.RunParallel(func(pb *testing.PB) {
-		for pb.Next() {
-			if got := SeqAtomicLoadInt(&seq, &data); got != want {
-				b.Fatalf("SeqAtomicLoadInt: got %v, wanted %v", got, want)
-			}
-		}
-	})
-}
-
-func BenchmarkSeqAtomicTryLoadIntUncontended(b *testing.B) {
-	var seq syncutil.SeqCount
-	const want = 42
-	data := want
-	b.RunParallel(func(pb *testing.PB) {
-		epoch := seq.BeginRead()
-		for pb.Next() {
-			if got, ok := SeqAtomicTryLoadInt(&seq, epoch, &data); !ok || got != want {
-				b.Fatalf("SeqAtomicTryLoadInt: got (%v, %v), wanted (%v, true)", got, ok, want)
-			}
-		}
-	})
-}
-
-// For comparison:
-func BenchmarkAtomicValueLoadIntUncontended(b *testing.B) {
-	var a atomic.Value
-	const want = 42
-	a.Store(int(want))
-	b.RunParallel(func(pb *testing.PB) {
-		for pb.Next() {
-			if got := a.Load().(int); got != want {
-				b.Fatalf("atomic.Value.Load: got %v, wanted %v", got, want)
-			}
-		}
-	})
-}
diff --git a/pkg/syncutil/seqcount.go b/pkg/syncutil/seqcount.go
deleted file mode 100644
index 11d8dbfaa..000000000
--- a/pkg/syncutil/seqcount.go
+++ /dev/null
@@ -1,149 +0,0 @@
-// Copyright 2019 The gVisor Authors.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package syncutil
-
-import (
-	"fmt"
-	"reflect"
-	"runtime"
-	"sync/atomic"
-)
-
-// SeqCount is a synchronization primitive for optimistic reader/writer
-// synchronization in cases where readers can work with stale data and
-// therefore do not need to block writers.
-//
-// Compared to sync/atomic.Value:
-//
-// - Mutation of SeqCount-protected data does not require memory allocation,
-// whereas atomic.Value generally does. This is a significant advantage when
-// writes are common.
-//
-// - Atomic reads of SeqCount-protected data require copying. This is a
-// disadvantage when atomic reads are common.
-//
-// - SeqCount may be more flexible: correct use of SeqCount.ReadOk allows other
-// operations to be made atomic with reads of SeqCount-protected data.
-//
-// - SeqCount may be less flexible: as of this writing, SeqCount-protected data
-// cannot include pointers.
-//
-// - SeqCount is more cumbersome to use; atomic reads of SeqCount-protected
-// data require instantiating function templates using go_generics (see
-// seqatomic.go).
-type SeqCount struct {
-	// epoch is incremented by BeginWrite and EndWrite, such that epoch is odd
-	// if a writer critical section is active, and a read from data protected
-	// by this SeqCount is atomic iff epoch is the same even value before and
-	// after the read.
-	epoch uint32
-}
-
-// SeqCountEpoch tracks writer critical sections in a SeqCount.
-type SeqCountEpoch struct {
-	val uint32
-}
-
-// We assume that:
-//
-// - All functions in sync/atomic that perform a memory read are at least a
-// read fence: memory reads before calls to such functions cannot be reordered
-// after the call, and memory reads after calls to such functions cannot be
-// reordered before the call, even if those reads do not use sync/atomic.
-//
-// - All functions in sync/atomic that perform a memory write are at least a
-// write fence: memory writes before calls to such functions cannot be
-// reordered after the call, and memory writes after calls to such functions
-// cannot be reordered before the call, even if those writes do not use
-// sync/atomic.
-//
-// As of this writing, the Go memory model completely fails to describe
-// sync/atomic, but these properties are implied by
-// https://groups.google.com/forum/#!topic/golang-nuts/7EnEhM3U7B8.
-
-// BeginRead indicates the beginning of a reader critical section. Reader
-// critical sections DO NOT BLOCK writer critical sections, so operations in a
-// reader critical section MAY RACE with writer critical sections. Races are
-// detected by ReadOk at the end of the reader critical section. Thus, the
-// low-level structure of readers is generally:
-//
-//     for {
-//         epoch := seq.BeginRead()
-//         // do something idempotent with seq-protected data
-//         if seq.ReadOk(epoch) {
-//             break
-//         }
-//     }
-//
-// However, since reader critical sections may race with writer critical
-// sections, the Go race detector will (accurately) flag data races in readers
-// using this pattern. Most users of SeqCount will need to use the
-// SeqAtomicLoad function template in seqatomic.go.
-func (s *SeqCount) BeginRead() SeqCountEpoch {
-	epoch := atomic.LoadUint32(&s.epoch)
-	for epoch&1 != 0 {
-		runtime.Gosched()
-		epoch = atomic.LoadUint32(&s.epoch)
-	}
-	return SeqCountEpoch{epoch}
-}
-
-// ReadOk returns true if the reader critical section initiated by a previous
-// call to BeginRead() that returned epoch did not race with any writer critical
-// sections.
-//
-// ReadOk may be called any number of times during a reader critical section.
-// Reader critical sections do not need to be explicitly terminated; the last
-// call to ReadOk is implicitly the end of the reader critical section.
-func (s *SeqCount) ReadOk(epoch SeqCountEpoch) bool {
-	return atomic.LoadUint32(&s.epoch) == epoch.val
-}
-
-// BeginWrite indicates the beginning of a writer critical section.
-//
-// SeqCount does not support concurrent writer critical sections; clients with
-// concurrent writers must synchronize them using e.g. sync.Mutex.
-func (s *SeqCount) BeginWrite() {
-	if epoch := atomic.AddUint32(&s.epoch, 1); epoch&1 == 0 {
-		panic("SeqCount.BeginWrite during writer critical section")
-	}
-}
-
-// EndWrite ends the effect of a preceding BeginWrite.
-func (s *SeqCount) EndWrite() {
-	if epoch := atomic.AddUint32(&s.epoch, 1); epoch&1 != 0 {
-		panic("SeqCount.EndWrite outside writer critical section")
-	}
-}
-
-// PointersInType returns a list of pointers reachable from values named
-// valName of the given type.
-//
-// PointersInType is not exhaustive, but it is guaranteed that if typ contains
-// at least one pointer, then PointersInTypeOf returns a non-empty list.
-func PointersInType(typ reflect.Type, valName string) []string {
-	switch kind := typ.Kind(); kind {
-	case reflect.Bool, reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr, reflect.Float32, reflect.Float64, reflect.Complex64, reflect.Complex128:
-		return nil
-
-	case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice, reflect.String, reflect.UnsafePointer:
-		return []string{valName}
-
-	case reflect.Array:
-		return PointersInType(typ.Elem(), valName+"[]")
-
-	case reflect.Struct:
-		var ptrs []string
-		for i, n := 0, typ.NumField(); i < n; i++ {
-			field := typ.Field(i)
-			ptrs = append(ptrs, PointersInType(field.Type, fmt.Sprintf("%s.%s", valName, field.Name))...)
-		}
-		return ptrs
-
-	default:
-		return []string{fmt.Sprintf("%s (of type %s with unknown kind %s)", valName, typ, kind)}
-	}
-}
diff --git a/pkg/syncutil/seqcount_test.go b/pkg/syncutil/seqcount_test.go
deleted file mode 100644
index 14d6aedea..000000000
--- a/pkg/syncutil/seqcount_test.go
+++ /dev/null
@@ -1,153 +0,0 @@
-// Copyright 2019 The gVisor Authors.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package syncutil
-
-import (
-	"reflect"
-	"testing"
-	"time"
-)
-
-func TestSeqCountWriteUncontended(t *testing.T) {
-	var seq SeqCount
-	seq.BeginWrite()
-	seq.EndWrite()
-}
-
-func TestSeqCountReadUncontended(t *testing.T) {
-	var seq SeqCount
-	epoch := seq.BeginRead()
-	if !seq.ReadOk(epoch) {
-		t.Errorf("ReadOk: got false, wanted true")
-	}
-}
-
-func TestSeqCountBeginReadAfterWrite(t *testing.T) {
-	var seq SeqCount
-	var data int32
-	const want = 1
-	seq.BeginWrite()
-	data = want
-	seq.EndWrite()
-	epoch := seq.BeginRead()
-	if data != want {
-		t.Errorf("Reader: got %v, wanted %v", data, want)
-	}
-	if !seq.ReadOk(epoch) {
-		t.Errorf("ReadOk: got false, wanted true")
-	}
-}
-
-func TestSeqCountBeginReadDuringWrite(t *testing.T) {
-	var seq SeqCount
-	var data int
-	const want = 1
-	seq.BeginWrite()
-	go func() {
-		time.Sleep(time.Second)
-		data = want
-		seq.EndWrite()
-	}()
-	epoch := seq.BeginRead()
-	if data != want {
-		t.Errorf("Reader: got %v, wanted %v", data, want)
-	}
-	if !seq.ReadOk(epoch) {
-		t.Errorf("ReadOk: got false, wanted true")
-	}
-}
-
-func TestSeqCountReadOkAfterWrite(t *testing.T) {
-	var seq SeqCount
-	epoch := seq.BeginRead()
-	seq.BeginWrite()
-	seq.EndWrite()
-	if seq.ReadOk(epoch) {
-		t.Errorf("ReadOk: got true, wanted false")
-	}
-}
-
-func TestSeqCountReadOkDuringWrite(t *testing.T) {
-	var seq SeqCount
-	epoch := seq.BeginRead()
-	seq.BeginWrite()
-	if seq.ReadOk(epoch) {
-		t.Errorf("ReadOk: got true, wanted false")
-	}
-	seq.EndWrite()
-}
-
-func BenchmarkSeqCountWriteUncontended(b *testing.B) {
-	var seq SeqCount
-	for i := 0; i < b.N; i++ {
-		seq.BeginWrite()
-		seq.EndWrite()
-	}
-}
-
-func BenchmarkSeqCountReadUncontended(b *testing.B) {
-	var seq SeqCount
-	b.RunParallel(func(pb *testing.PB) {
-		for pb.Next() {
-			epoch := seq.BeginRead()
-			if !seq.ReadOk(epoch) {
-				b.Fatalf("ReadOk: got false, wanted true")
-			}
-		}
-	})
-}
-
-func TestPointersInType(t *testing.T) {
-	for _, test := range []struct {
-		name string // used for both test and value name
-		val  interface{}
-		ptrs []string
-	}{
-		{
-			name: "EmptyStruct",
-			val:  struct{}{},
-		},
-		{
-			name: "Int",
-			val:  int(0),
-		},
-		{
-			name: "MixedStruct",
-			val: struct {
-				b             bool
-				I             int
-				ExportedPtr   *struct{}
-				unexportedPtr *struct{}
-				arr           [2]int
-				ptrArr        [2]*int
-				nestedStruct  struct {
-					nestedNonptr int
-					nestedPtr    *int
-				}
-				structArr [1]struct {
-					nonptr int
-					ptr    *int
-				}
-			}{},
-			ptrs: []string{
-				"MixedStruct.ExportedPtr",
-				"MixedStruct.unexportedPtr",
-				"MixedStruct.ptrArr[]",
-				"MixedStruct.nestedStruct.nestedPtr",
-				"MixedStruct.structArr[].ptr",
-			},
-		},
-	} {
-		t.Run(test.name, func(t *testing.T) {
-			typ := reflect.TypeOf(test.val)
-			ptrs := PointersInType(typ, test.name)
-			t.Logf("Found pointers: %v", ptrs)
-			if (len(ptrs) != 0 || len(test.ptrs) != 0) && !reflect.DeepEqual(ptrs, test.ptrs) {
-				t.Errorf("Got %v, wanted %v", ptrs, test.ptrs)
-			}
-		})
-	}
-}
diff --git a/pkg/syncutil/syncutil.go b/pkg/syncutil/syncutil.go
deleted file mode 100644
index 66e750d06..000000000
--- a/pkg/syncutil/syncutil.go
+++ /dev/null
@@ -1,7 +0,0 @@
-// Copyright 2019 The gVisor Authors.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package syncutil provides synchronization primitives.
-package syncutil
diff --git a/pkg/tcpip/BUILD b/pkg/tcpip/BUILD
index e07ebd153..db06d02c6 100644
--- a/pkg/tcpip/BUILD
+++ b/pkg/tcpip/BUILD
@@ -15,6 +15,7 @@ go_library(
     importpath = "gvisor.dev/gvisor/pkg/tcpip",
     visibility = ["//visibility:public"],
     deps = [
+        "//pkg/sync",
         "//pkg/tcpip/buffer",
         "//pkg/tcpip/iptables",
         "//pkg/waiter",
diff --git a/pkg/tcpip/adapters/gonet/BUILD b/pkg/tcpip/adapters/gonet/BUILD
index 78df5a0b1..3df7d18d3 100644
--- a/pkg/tcpip/adapters/gonet/BUILD
+++ b/pkg/tcpip/adapters/gonet/BUILD
@@ -9,6 +9,7 @@ go_library(
     importpath = "gvisor.dev/gvisor/pkg/tcpip/adapters/gonet",
     visibility = ["//visibility:public"],
     deps = [
+        "//pkg/sync",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
         "//pkg/tcpip/stack",
diff --git a/pkg/tcpip/adapters/gonet/gonet.go b/pkg/tcpip/adapters/gonet/gonet.go
index cd6ce930a..a2f44b496 100644
--- a/pkg/tcpip/adapters/gonet/gonet.go
+++ b/pkg/tcpip/adapters/gonet/gonet.go
@@ -20,9 +20,9 @@ import (
 	"errors"
 	"io"
 	"net"
-	"sync"
 	"time"
 
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
diff --git a/pkg/tcpip/link/fdbased/BUILD b/pkg/tcpip/link/fdbased/BUILD
index 897c94821..66cc53ed4 100644
--- a/pkg/tcpip/link/fdbased/BUILD
+++ b/pkg/tcpip/link/fdbased/BUILD
@@ -16,6 +16,7 @@ go_library(
     importpath = "gvisor.dev/gvisor/pkg/tcpip/link/fdbased",
     visibility = ["//visibility:public"],
     deps = [
+        "//pkg/sync",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
         "//pkg/tcpip/header",
diff --git a/pkg/tcpip/link/fdbased/endpoint.go b/pkg/tcpip/link/fdbased/endpoint.go
index fa8a703d9..b7f60178e 100644
--- a/pkg/tcpip/link/fdbased/endpoint.go
+++ b/pkg/tcpip/link/fdbased/endpoint.go
@@ -41,10 +41,10 @@ package fdbased
 
 import (
 	"fmt"
-	"sync"
 	"syscall"
 
 	"golang.org/x/sys/unix"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
diff --git a/pkg/tcpip/link/sharedmem/BUILD b/pkg/tcpip/link/sharedmem/BUILD
index a4f9cdd69..09165dd4c 100644
--- a/pkg/tcpip/link/sharedmem/BUILD
+++ b/pkg/tcpip/link/sharedmem/BUILD
@@ -15,6 +15,7 @@ go_library(
     visibility = ["//visibility:public"],
     deps = [
         "//pkg/log",
+        "//pkg/sync",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
         "//pkg/tcpip/header",
@@ -31,6 +32,7 @@ go_test(
     ],
     embed = [":sharedmem"],
     deps = [
+        "//pkg/sync",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
         "//pkg/tcpip/header",
diff --git a/pkg/tcpip/link/sharedmem/pipe/BUILD b/pkg/tcpip/link/sharedmem/pipe/BUILD
index 6b5bc542c..a0d4ad0be 100644
--- a/pkg/tcpip/link/sharedmem/pipe/BUILD
+++ b/pkg/tcpip/link/sharedmem/pipe/BUILD
@@ -21,4 +21,5 @@ go_test(
         "pipe_test.go",
     ],
     embed = [":pipe"],
+    deps = ["//pkg/sync"],
 )
diff --git a/pkg/tcpip/link/sharedmem/pipe/pipe_test.go b/pkg/tcpip/link/sharedmem/pipe/pipe_test.go
index 59ef69a8b..dc239a0d0 100644
--- a/pkg/tcpip/link/sharedmem/pipe/pipe_test.go
+++ b/pkg/tcpip/link/sharedmem/pipe/pipe_test.go
@@ -18,8 +18,9 @@ import (
 	"math/rand"
 	"reflect"
 	"runtime"
-	"sync"
 	"testing"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 func TestSimpleReadWrite(t *testing.T) {
diff --git a/pkg/tcpip/link/sharedmem/sharedmem.go b/pkg/tcpip/link/sharedmem/sharedmem.go
index 080f9d667..655e537c4 100644
--- a/pkg/tcpip/link/sharedmem/sharedmem.go
+++ b/pkg/tcpip/link/sharedmem/sharedmem.go
@@ -23,11 +23,11 @@
 package sharedmem
 
 import (
-	"sync"
 	"sync/atomic"
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
diff --git a/pkg/tcpip/link/sharedmem/sharedmem_test.go b/pkg/tcpip/link/sharedmem/sharedmem_test.go
index 89603c48f..5c729a439 100644
--- a/pkg/tcpip/link/sharedmem/sharedmem_test.go
+++ b/pkg/tcpip/link/sharedmem/sharedmem_test.go
@@ -22,11 +22,11 @@ import (
 	"math/rand"
 	"os"
 	"strings"
-	"sync"
 	"syscall"
 	"testing"
 	"time"
 
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
diff --git a/pkg/tcpip/network/fragmentation/BUILD b/pkg/tcpip/network/fragmentation/BUILD
index acf1e022c..ed16076fd 100644
--- a/pkg/tcpip/network/fragmentation/BUILD
+++ b/pkg/tcpip/network/fragmentation/BUILD
@@ -28,6 +28,7 @@ go_library(
     visibility = ["//visibility:public"],
     deps = [
         "//pkg/log",
+        "//pkg/sync",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
     ],
diff --git a/pkg/tcpip/network/fragmentation/fragmentation.go b/pkg/tcpip/network/fragmentation/fragmentation.go
index 6da5238ec..92f2aa13a 100644
--- a/pkg/tcpip/network/fragmentation/fragmentation.go
+++ b/pkg/tcpip/network/fragmentation/fragmentation.go
@@ -19,9 +19,9 @@ package fragmentation
 import (
 	"fmt"
 	"log"
-	"sync"
 	"time"
 
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 )
 
diff --git a/pkg/tcpip/network/fragmentation/reassembler.go b/pkg/tcpip/network/fragmentation/reassembler.go
index 9e002e396..0a83d81f2 100644
--- a/pkg/tcpip/network/fragmentation/reassembler.go
+++ b/pkg/tcpip/network/fragmentation/reassembler.go
@@ -18,9 +18,9 @@ import (
 	"container/heap"
 	"fmt"
 	"math"
-	"sync"
 	"time"
 
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 )
 
diff --git a/pkg/tcpip/ports/BUILD b/pkg/tcpip/ports/BUILD
index e156b01f6..a6ef3bdcc 100644
--- a/pkg/tcpip/ports/BUILD
+++ b/pkg/tcpip/ports/BUILD
@@ -9,6 +9,7 @@ go_library(
     importpath = "gvisor.dev/gvisor/pkg/tcpip/ports",
     visibility = ["//visibility:public"],
     deps = [
+        "//pkg/sync",
         "//pkg/tcpip",
     ],
 )
diff --git a/pkg/tcpip/ports/ports.go b/pkg/tcpip/ports/ports.go
index 6c5e19e8f..b937cb84b 100644
--- a/pkg/tcpip/ports/ports.go
+++ b/pkg/tcpip/ports/ports.go
@@ -18,9 +18,9 @@ package ports
 import (
 	"math"
 	"math/rand"
-	"sync"
 	"sync/atomic"
 
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 )
 
diff --git a/pkg/tcpip/stack/BUILD b/pkg/tcpip/stack/BUILD
index 826fca4de..6a8654105 100644
--- a/pkg/tcpip/stack/BUILD
+++ b/pkg/tcpip/stack/BUILD
@@ -36,6 +36,7 @@ go_library(
         "//pkg/ilist",
         "//pkg/rand",
         "//pkg/sleep",
+        "//pkg/sync",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
         "//pkg/tcpip/hash/jenkins",
@@ -80,6 +81,7 @@ go_test(
     embed = [":stack"],
     deps = [
         "//pkg/sleep",
+        "//pkg/sync",
         "//pkg/tcpip",
     ],
 )
diff --git a/pkg/tcpip/stack/linkaddrcache.go b/pkg/tcpip/stack/linkaddrcache.go
index 267df60d1..403557fd7 100644
--- a/pkg/tcpip/stack/linkaddrcache.go
+++ b/pkg/tcpip/stack/linkaddrcache.go
@@ -16,10 +16,10 @@ package stack
 
 import (
 	"fmt"
-	"sync"
 	"time"
 
 	"gvisor.dev/gvisor/pkg/sleep"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 )
 
diff --git a/pkg/tcpip/stack/linkaddrcache_test.go b/pkg/tcpip/stack/linkaddrcache_test.go
index 9946b8fe8..1baa498d0 100644
--- a/pkg/tcpip/stack/linkaddrcache_test.go
+++ b/pkg/tcpip/stack/linkaddrcache_test.go
@@ -16,12 +16,12 @@ package stack
 
 import (
 	"fmt"
-	"sync"
 	"sync/atomic"
 	"testing"
 	"time"
 
 	"gvisor.dev/gvisor/pkg/sleep"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 )
 
diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go
index 3810c6602..fe557ccbd 100644
--- a/pkg/tcpip/stack/nic.go
+++ b/pkg/tcpip/stack/nic.go
@@ -16,9 +16,9 @@ package stack
 
 import (
 	"strings"
-	"sync"
 	"sync/atomic"
 
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 41bf9fd9b..a47ceba54 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -21,13 +21,13 @@ package stack
 
 import (
 	"encoding/binary"
-	"sync"
 	"sync/atomic"
 	"time"
 
 	"golang.org/x/time/rate"
 	"gvisor.dev/gvisor/pkg/rand"
 	"gvisor.dev/gvisor/pkg/sleep"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
diff --git a/pkg/tcpip/stack/transport_demuxer.go b/pkg/tcpip/stack/transport_demuxer.go
index 67c21be42..f384a91de 100644
--- a/pkg/tcpip/stack/transport_demuxer.go
+++ b/pkg/tcpip/stack/transport_demuxer.go
@@ -18,8 +18,8 @@ import (
 	"fmt"
 	"math/rand"
 	"sort"
-	"sync"
 
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/hash/jenkins"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go
index 72b5ce179..4a090ac86 100644
--- a/pkg/tcpip/tcpip.go
+++ b/pkg/tcpip/tcpip.go
@@ -35,10 +35,10 @@ import (
 	"reflect"
 	"strconv"
 	"strings"
-	"sync"
 	"sync/atomic"
 	"time"
 
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/iptables"
 	"gvisor.dev/gvisor/pkg/waiter"
diff --git a/pkg/tcpip/transport/icmp/BUILD b/pkg/tcpip/transport/icmp/BUILD
index d8c5b5058..3aa23d529 100644
--- a/pkg/tcpip/transport/icmp/BUILD
+++ b/pkg/tcpip/transport/icmp/BUILD
@@ -28,6 +28,7 @@ go_library(
     visibility = ["//visibility:public"],
     deps = [
         "//pkg/sleep",
+        "//pkg/sync",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
         "//pkg/tcpip/header",
diff --git a/pkg/tcpip/transport/icmp/endpoint.go b/pkg/tcpip/transport/icmp/endpoint.go
index c7ce74cdd..330786f4c 100644
--- a/pkg/tcpip/transport/icmp/endpoint.go
+++ b/pkg/tcpip/transport/icmp/endpoint.go
@@ -15,8 +15,7 @@
 package icmp
 
 import (
-	"sync"
-
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
diff --git a/pkg/tcpip/transport/packet/BUILD b/pkg/tcpip/transport/packet/BUILD
index 44b58ff6b..4858d150c 100644
--- a/pkg/tcpip/transport/packet/BUILD
+++ b/pkg/tcpip/transport/packet/BUILD
@@ -28,6 +28,7 @@ go_library(
     deps = [
         "//pkg/log",
         "//pkg/sleep",
+        "//pkg/sync",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
         "//pkg/tcpip/header",
diff --git a/pkg/tcpip/transport/packet/endpoint.go b/pkg/tcpip/transport/packet/endpoint.go
index 07ffa8aba..fc5bc69fa 100644
--- a/pkg/tcpip/transport/packet/endpoint.go
+++ b/pkg/tcpip/transport/packet/endpoint.go
@@ -25,8 +25,7 @@
 package packet
 
 import (
-	"sync"
-
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
diff --git a/pkg/tcpip/transport/raw/BUILD b/pkg/tcpip/transport/raw/BUILD
index 00991ac8e..2f2131ff7 100644
--- a/pkg/tcpip/transport/raw/BUILD
+++ b/pkg/tcpip/transport/raw/BUILD
@@ -29,6 +29,7 @@ go_library(
     deps = [
         "//pkg/log",
         "//pkg/sleep",
+        "//pkg/sync",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
         "//pkg/tcpip/header",
diff --git a/pkg/tcpip/transport/raw/endpoint.go b/pkg/tcpip/transport/raw/endpoint.go
index 85f7eb76b..ee9c4c58b 100644
--- a/pkg/tcpip/transport/raw/endpoint.go
+++ b/pkg/tcpip/transport/raw/endpoint.go
@@ -26,8 +26,7 @@
 package raw
 
 import (
-	"sync"
-
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
diff --git a/pkg/tcpip/transport/tcp/BUILD b/pkg/tcpip/transport/tcp/BUILD
index 3b353d56c..353bd06f4 100644
--- a/pkg/tcpip/transport/tcp/BUILD
+++ b/pkg/tcpip/transport/tcp/BUILD
@@ -48,6 +48,7 @@ go_library(
         "//pkg/log",
         "//pkg/rand",
         "//pkg/sleep",
+        "//pkg/sync",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
         "//pkg/tcpip/hash/jenkins",
diff --git a/pkg/tcpip/transport/tcp/accept.go b/pkg/tcpip/transport/tcp/accept.go
index 5422ae80c..1ea996936 100644
--- a/pkg/tcpip/transport/tcp/accept.go
+++ b/pkg/tcpip/transport/tcp/accept.go
@@ -19,11 +19,11 @@ import (
 	"encoding/binary"
 	"hash"
 	"io"
-	"sync"
 	"time"
 
 	"gvisor.dev/gvisor/pkg/rand"
 	"gvisor.dev/gvisor/pkg/sleep"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
diff --git a/pkg/tcpip/transport/tcp/connect.go b/pkg/tcpip/transport/tcp/connect.go
index cdd69f360..613ec1775 100644
--- a/pkg/tcpip/transport/tcp/connect.go
+++ b/pkg/tcpip/transport/tcp/connect.go
@@ -16,11 +16,11 @@ package tcp
 
 import (
 	"encoding/binary"
-	"sync"
 	"time"
 
 	"gvisor.dev/gvisor/pkg/rand"
 	"gvisor.dev/gvisor/pkg/sleep"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/hash/jenkins"
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index 830bc1e3e..cca511fb9 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -19,12 +19,12 @@ import (
 	"fmt"
 	"math"
 	"strings"
-	"sync"
 	"sync/atomic"
 	"time"
 
 	"gvisor.dev/gvisor/pkg/rand"
 	"gvisor.dev/gvisor/pkg/sleep"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/hash/jenkins"
diff --git a/pkg/tcpip/transport/tcp/endpoint_state.go b/pkg/tcpip/transport/tcp/endpoint_state.go
index 7aa4c3f0e..4b8d867bc 100644
--- a/pkg/tcpip/transport/tcp/endpoint_state.go
+++ b/pkg/tcpip/transport/tcp/endpoint_state.go
@@ -16,9 +16,9 @@ package tcp
 
 import (
 	"fmt"
-	"sync"
 	"time"
 
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
diff --git a/pkg/tcpip/transport/tcp/forwarder.go b/pkg/tcpip/transport/tcp/forwarder.go
index 4983bca81..7eb613be5 100644
--- a/pkg/tcpip/transport/tcp/forwarder.go
+++ b/pkg/tcpip/transport/tcp/forwarder.go
@@ -15,8 +15,7 @@
 package tcp
 
 import (
-	"sync"
-
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
 	"gvisor.dev/gvisor/pkg/tcpip/seqnum"
diff --git a/pkg/tcpip/transport/tcp/protocol.go b/pkg/tcpip/transport/tcp/protocol.go
index bc718064c..9a8f64aa6 100644
--- a/pkg/tcpip/transport/tcp/protocol.go
+++ b/pkg/tcpip/transport/tcp/protocol.go
@@ -22,9 +22,9 @@ package tcp
 
 import (
 	"strings"
-	"sync"
 	"time"
 
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
diff --git a/pkg/tcpip/transport/tcp/segment_queue.go b/pkg/tcpip/transport/tcp/segment_queue.go
index e0759225e..bd20a7ee9 100644
--- a/pkg/tcpip/transport/tcp/segment_queue.go
+++ b/pkg/tcpip/transport/tcp/segment_queue.go
@@ -15,7 +15,7 @@
 package tcp
 
 import (
-	"sync"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // segmentQueue is a bounded, thread-safe queue of TCP segments.
diff --git a/pkg/tcpip/transport/tcp/snd.go b/pkg/tcpip/transport/tcp/snd.go
index 8a947dc66..79f2d274b 100644
--- a/pkg/tcpip/transport/tcp/snd.go
+++ b/pkg/tcpip/transport/tcp/snd.go
@@ -16,11 +16,11 @@ package tcp
 
 import (
 	"math"
-	"sync"
 	"sync/atomic"
 	"time"
 
 	"gvisor.dev/gvisor/pkg/sleep"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
diff --git a/pkg/tcpip/transport/udp/BUILD b/pkg/tcpip/transport/udp/BUILD
index 97e4d5825..57ff123e3 100644
--- a/pkg/tcpip/transport/udp/BUILD
+++ b/pkg/tcpip/transport/udp/BUILD
@@ -30,6 +30,7 @@ go_library(
     visibility = ["//visibility:public"],
     deps = [
         "//pkg/sleep",
+        "//pkg/sync",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
         "//pkg/tcpip/header",
diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go
index 864dc8733..a4ff29a7d 100644
--- a/pkg/tcpip/transport/udp/endpoint.go
+++ b/pkg/tcpip/transport/udp/endpoint.go
@@ -15,8 +15,7 @@
 package udp
 
 import (
-	"sync"
-
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
diff --git a/pkg/tmutex/BUILD b/pkg/tmutex/BUILD
index 6afdb29b7..07778e4f7 100644
--- a/pkg/tmutex/BUILD
+++ b/pkg/tmutex/BUILD
@@ -15,4 +15,5 @@ go_test(
     size = "medium",
     srcs = ["tmutex_test.go"],
     embed = [":tmutex"],
+    deps = ["//pkg/sync"],
 )
diff --git a/pkg/tmutex/tmutex_test.go b/pkg/tmutex/tmutex_test.go
index ce34c7962..05540696a 100644
--- a/pkg/tmutex/tmutex_test.go
+++ b/pkg/tmutex/tmutex_test.go
@@ -17,10 +17,11 @@ package tmutex
 import (
 	"fmt"
 	"runtime"
-	"sync"
 	"sync/atomic"
 	"testing"
 	"time"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 func TestBasicLock(t *testing.T) {
diff --git a/pkg/unet/BUILD b/pkg/unet/BUILD
index 8f6f180e5..d1885ae66 100644
--- a/pkg/unet/BUILD
+++ b/pkg/unet/BUILD
@@ -24,4 +24,5 @@ go_test(
         "unet_test.go",
     ],
     embed = [":unet"],
+    deps = ["//pkg/sync"],
 )
diff --git a/pkg/unet/unet_test.go b/pkg/unet/unet_test.go
index a3cc6f5d3..5c4b9e8e9 100644
--- a/pkg/unet/unet_test.go
+++ b/pkg/unet/unet_test.go
@@ -19,10 +19,11 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
-	"sync"
 	"syscall"
 	"testing"
 	"time"
+
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 func randomFilename() (string, error) {
diff --git a/pkg/urpc/BUILD b/pkg/urpc/BUILD
index b6bbb0ea2..b8fdc3125 100644
--- a/pkg/urpc/BUILD
+++ b/pkg/urpc/BUILD
@@ -11,6 +11,7 @@ go_library(
     deps = [
         "//pkg/fd",
         "//pkg/log",
+        "//pkg/sync",
         "//pkg/unet",
     ],
 )
diff --git a/pkg/urpc/urpc.go b/pkg/urpc/urpc.go
index df59ffab1..13b2ea314 100644
--- a/pkg/urpc/urpc.go
+++ b/pkg/urpc/urpc.go
@@ -27,10 +27,10 @@ import (
 	"os"
 	"reflect"
 	"runtime"
-	"sync"
 
 	"gvisor.dev/gvisor/pkg/fd"
 	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/unet"
 )
 
diff --git a/pkg/waiter/BUILD b/pkg/waiter/BUILD
index 0427bc41f..1c6890e52 100644
--- a/pkg/waiter/BUILD
+++ b/pkg/waiter/BUILD
@@ -24,6 +24,7 @@ go_library(
     ],
     importpath = "gvisor.dev/gvisor/pkg/waiter",
     visibility = ["//visibility:public"],
+    deps = ["//pkg/sync"],
 )
 
 go_test(
diff --git a/pkg/waiter/waiter.go b/pkg/waiter/waiter.go
index 8a65ed164..f708e95fa 100644
--- a/pkg/waiter/waiter.go
+++ b/pkg/waiter/waiter.go
@@ -58,7 +58,7 @@
 package waiter
 
 import (
-	"sync"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // EventMask represents io events as used in the poll() syscall.
diff --git a/runsc/boot/BUILD b/runsc/boot/BUILD
index 6226b63f8..3e20f8f2f 100644
--- a/runsc/boot/BUILD
+++ b/runsc/boot/BUILD
@@ -74,6 +74,7 @@ go_library(
         "//pkg/sentry/usage",
         "//pkg/sentry/usermem",
         "//pkg/sentry/watchdog",
+        "//pkg/sync",
         "//pkg/syserror",
         "//pkg/tcpip",
         "//pkg/tcpip/link/fdbased",
@@ -114,6 +115,7 @@ go_test(
         "//pkg/sentry/context/contexttest",
         "//pkg/sentry/fs",
         "//pkg/sentry/kernel/auth",
+        "//pkg/sync",
         "//pkg/unet",
         "//runsc/fsgofer",
         "@com_github_opencontainers_runtime-spec//specs-go:go_default_library",
diff --git a/runsc/boot/compat.go b/runsc/boot/compat.go
index 352e710d2..9c23b9553 100644
--- a/runsc/boot/compat.go
+++ b/runsc/boot/compat.go
@@ -17,7 +17,6 @@ package boot
 import (
 	"fmt"
 	"os"
-	"sync"
 	"syscall"
 
 	"github.com/golang/protobuf/proto"
@@ -27,6 +26,7 @@ import (
 	ucspb "gvisor.dev/gvisor/pkg/sentry/kernel/uncaught_signal_go_proto"
 	"gvisor.dev/gvisor/pkg/sentry/strace"
 	spb "gvisor.dev/gvisor/pkg/sentry/unimpl/unimplemented_syscall_go_proto"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 func initCompatLogs(fd int) error {
diff --git a/runsc/boot/limits.go b/runsc/boot/limits.go
index d1c0bb9b5..ce62236e5 100644
--- a/runsc/boot/limits.go
+++ b/runsc/boot/limits.go
@@ -16,12 +16,12 @@ package boot
 
 import (
 	"fmt"
-	"sync"
 	"syscall"
 
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/limits"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 // Mapping from linux resource names to limits.LimitType.
diff --git a/runsc/boot/loader.go b/runsc/boot/loader.go
index bc1d0c1bb..fad72f4ab 100644
--- a/runsc/boot/loader.go
+++ b/runsc/boot/loader.go
@@ -20,7 +20,6 @@ import (
 	mrand "math/rand"
 	"os"
 	"runtime"
-	"sync"
 	"sync/atomic"
 	"syscall"
 	gtime "time"
@@ -46,6 +45,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/time"
 	"gvisor.dev/gvisor/pkg/sentry/usage"
 	"gvisor.dev/gvisor/pkg/sentry/watchdog"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/link/sniffer"
 	"gvisor.dev/gvisor/pkg/tcpip/network/arp"
diff --git a/runsc/boot/loader_test.go b/runsc/boot/loader_test.go
index 147ff7703..bec0dc292 100644
--- a/runsc/boot/loader_test.go
+++ b/runsc/boot/loader_test.go
@@ -19,7 +19,6 @@ import (
 	"math/rand"
 	"os"
 	"reflect"
-	"sync"
 	"syscall"
 	"testing"
 	"time"
@@ -30,6 +29,7 @@ import (
 	"gvisor.dev/gvisor/pkg/p9"
 	"gvisor.dev/gvisor/pkg/sentry/context/contexttest"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/unet"
 	"gvisor.dev/gvisor/runsc/fsgofer"
 )
diff --git a/runsc/cmd/BUILD b/runsc/cmd/BUILD
index 250845ad7..b94bc4fa0 100644
--- a/runsc/cmd/BUILD
+++ b/runsc/cmd/BUILD
@@ -44,6 +44,7 @@ go_library(
         "//pkg/sentry/control",
         "//pkg/sentry/kernel",
         "//pkg/sentry/kernel/auth",
+        "//pkg/sync",
         "//pkg/unet",
         "//pkg/urpc",
         "//runsc/boot",
diff --git a/runsc/cmd/create.go b/runsc/cmd/create.go
index a4e3071b3..1815c93b9 100644
--- a/runsc/cmd/create.go
+++ b/runsc/cmd/create.go
@@ -16,6 +16,7 @@ package cmd
 
 import (
 	"context"
+
 	"flag"
 	"github.com/google/subcommands"
 	"gvisor.dev/gvisor/runsc/boot"
diff --git a/runsc/cmd/gofer.go b/runsc/cmd/gofer.go
index 4831210c0..7df7995f0 100644
--- a/runsc/cmd/gofer.go
+++ b/runsc/cmd/gofer.go
@@ -21,7 +21,6 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
-	"sync"
 	"syscall"
 
 	"flag"
@@ -30,6 +29,7 @@ import (
 	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/p9"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/unet"
 	"gvisor.dev/gvisor/runsc/boot"
 	"gvisor.dev/gvisor/runsc/fsgofer"
diff --git a/runsc/cmd/start.go b/runsc/cmd/start.go
index de2115dff..5e9bc53ab 100644
--- a/runsc/cmd/start.go
+++ b/runsc/cmd/start.go
@@ -16,6 +16,7 @@ package cmd
 
 import (
 	"context"
+
 	"flag"
 	"github.com/google/subcommands"
 	"gvisor.dev/gvisor/runsc/boot"
diff --git a/runsc/container/BUILD b/runsc/container/BUILD
index 2bd12120d..6dea179e4 100644
--- a/runsc/container/BUILD
+++ b/runsc/container/BUILD
@@ -18,6 +18,7 @@ go_library(
     deps = [
         "//pkg/log",
         "//pkg/sentry/control",
+        "//pkg/sync",
         "//runsc/boot",
         "//runsc/cgroup",
         "//runsc/sandbox",
@@ -53,6 +54,7 @@ go_test(
         "//pkg/sentry/control",
         "//pkg/sentry/kernel",
         "//pkg/sentry/kernel/auth",
+        "//pkg/sync",
         "//pkg/unet",
         "//pkg/urpc",
         "//runsc/boot",
diff --git a/runsc/container/console_test.go b/runsc/container/console_test.go
index 5ed131a7f..060b63bf3 100644
--- a/runsc/container/console_test.go
+++ b/runsc/container/console_test.go
@@ -20,7 +20,6 @@ import (
 	"io"
 	"os"
 	"path/filepath"
-	"sync"
 	"syscall"
 	"testing"
 	"time"
@@ -29,6 +28,7 @@ import (
 	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/sentry/control"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/unet"
 	"gvisor.dev/gvisor/pkg/urpc"
 	"gvisor.dev/gvisor/runsc/testutil"
diff --git a/runsc/container/container_test.go b/runsc/container/container_test.go
index c10f85992..b54d8f712 100644
--- a/runsc/container/container_test.go
+++ b/runsc/container/container_test.go
@@ -26,7 +26,6 @@ import (
 	"reflect"
 	"strconv"
 	"strings"
-	"sync"
 	"syscall"
 	"testing"
 	"time"
@@ -39,6 +38,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/control"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/runsc/boot"
 	"gvisor.dev/gvisor/runsc/boot/platforms"
 	"gvisor.dev/gvisor/runsc/specutils"
diff --git a/runsc/container/multi_container_test.go b/runsc/container/multi_container_test.go
index 4ad09ceab..2da93ec5b 100644
--- a/runsc/container/multi_container_test.go
+++ b/runsc/container/multi_container_test.go
@@ -22,7 +22,6 @@ import (
 	"path"
 	"path/filepath"
 	"strings"
-	"sync"
 	"syscall"
 	"testing"
 	"time"
@@ -30,6 +29,7 @@ import (
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 	"gvisor.dev/gvisor/pkg/sentry/control"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/runsc/boot"
 	"gvisor.dev/gvisor/runsc/specutils"
 	"gvisor.dev/gvisor/runsc/testutil"
diff --git a/runsc/container/state_file.go b/runsc/container/state_file.go
index d95151ea5..17a251530 100644
--- a/runsc/container/state_file.go
+++ b/runsc/container/state_file.go
@@ -20,10 +20,10 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
-	"sync"
 
 	"github.com/gofrs/flock"
 	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/sync"
 )
 
 const stateFileExtension = ".state"
diff --git a/runsc/fsgofer/BUILD b/runsc/fsgofer/BUILD
index afcb41801..a9582d92b 100644
--- a/runsc/fsgofer/BUILD
+++ b/runsc/fsgofer/BUILD
@@ -19,6 +19,7 @@ go_library(
         "//pkg/fd",
         "//pkg/log",
         "//pkg/p9",
+        "//pkg/sync",
         "//pkg/syserr",
         "//runsc/specutils",
         "@org_golang_x_sys//unix:go_default_library",
diff --git a/runsc/fsgofer/fsgofer.go b/runsc/fsgofer/fsgofer.go
index b59e1a70e..93606d051 100644
--- a/runsc/fsgofer/fsgofer.go
+++ b/runsc/fsgofer/fsgofer.go
@@ -29,7 +29,6 @@ import (
 	"path/filepath"
 	"runtime"
 	"strconv"
-	"sync"
 	"syscall"
 
 	"golang.org/x/sys/unix"
@@ -37,6 +36,7 @@ import (
 	"gvisor.dev/gvisor/pkg/fd"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/p9"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/runsc/specutils"
 )
 
diff --git a/runsc/sandbox/BUILD b/runsc/sandbox/BUILD
index 8001949d5..ddbc37456 100644
--- a/runsc/sandbox/BUILD
+++ b/runsc/sandbox/BUILD
@@ -19,6 +19,7 @@ go_library(
         "//pkg/log",
         "//pkg/sentry/control",
         "//pkg/sentry/platform",
+        "//pkg/sync",
         "//pkg/tcpip/header",
         "//pkg/tcpip/stack",
         "//pkg/urpc",
diff --git a/runsc/sandbox/sandbox.go b/runsc/sandbox/sandbox.go
index ce1452b87..ec72bdbfd 100644
--- a/runsc/sandbox/sandbox.go
+++ b/runsc/sandbox/sandbox.go
@@ -22,7 +22,6 @@ import (
 	"os"
 	"os/exec"
 	"strconv"
-	"sync"
 	"syscall"
 	"time"
 
@@ -34,6 +33,7 @@ import (
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/control"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/urpc"
 	"gvisor.dev/gvisor/runsc/boot"
 	"gvisor.dev/gvisor/runsc/boot/platforms"
diff --git a/runsc/testutil/BUILD b/runsc/testutil/BUILD
index c96ca2eb6..3c3027cb5 100644
--- a/runsc/testutil/BUILD
+++ b/runsc/testutil/BUILD
@@ -10,6 +10,7 @@ go_library(
     visibility = ["//:sandbox"],
     deps = [
         "//pkg/log",
+        "//pkg/sync",
         "//runsc/boot",
         "//runsc/specutils",
         "@com_github_cenkalti_backoff//:go_default_library",
diff --git a/runsc/testutil/testutil.go b/runsc/testutil/testutil.go
index 9632776d2..fb22eae39 100644
--- a/runsc/testutil/testutil.go
+++ b/runsc/testutil/testutil.go
@@ -34,7 +34,6 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
-	"sync"
 	"sync/atomic"
 	"syscall"
 	"time"
@@ -42,6 +41,7 @@ import (
 	"github.com/cenkalti/backoff"
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/runsc/boot"
 	"gvisor.dev/gvisor/runsc/specutils"
 )
-- 
cgit v1.2.3


From dacd349d6fb4fc7453b1fbf694158fd25496ed42 Mon Sep 17 00:00:00 2001
From: Bhasker Hariharan <bhaskerh@google.com>
Date: Fri, 10 Jan 2020 06:01:10 -0800
Subject: panic fix in retransmitTimerExpired.

This is a band-aid fix for now to prevent panics.

PiperOrigin-RevId: 289078453
---
 pkg/tcpip/transport/tcp/snd.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/pkg/tcpip/transport/tcp/snd.go b/pkg/tcpip/transport/tcp/snd.go
index 79f2d274b..fdff7ed81 100644
--- a/pkg/tcpip/transport/tcp/snd.go
+++ b/pkg/tcpip/transport/tcp/snd.go
@@ -442,6 +442,13 @@ func (s *sender) retransmitTimerExpired() bool {
 		return true
 	}
 
+	// TODO(b/147297758): Band-aid fix, retransmitTimer can fire in some edge cases
+	// when writeList is empty. Remove this once we have a proper fix for this
+	// issue.
+	if s.writeList.Front() == nil {
+		return true
+	}
+
 	s.ep.stack.Stats().TCP.Timeouts.Increment()
 	s.ep.stats.SendErrors.Timeouts.Increment()
 
-- 
cgit v1.2.3


From 6b83111499e9a8f42b6aa3998839922ba70eefdc Mon Sep 17 00:00:00 2001
From: Ian Gudger <igudger@google.com>
Date: Fri, 10 Jan 2020 13:33:12 -0800
Subject: goid: new package

Allows retrieving the goroutine ID for concurrency testing when the race
detector is enabled.

Updates #1472

PiperOrigin-RevId: 289155308
---
 pkg/goid/BUILD          | 26 +++++++++++++++++
 pkg/goid/empty_test.go  | 22 +++++++++++++++
 pkg/goid/goid.go        | 24 ++++++++++++++++
 pkg/goid/goid_amd64.s   | 21 ++++++++++++++
 pkg/goid/goid_race.go   | 25 +++++++++++++++++
 pkg/goid/goid_test.go   | 74 +++++++++++++++++++++++++++++++++++++++++++++++++
 pkg/goid/goid_unsafe.go | 64 ++++++++++++++++++++++++++++++++++++++++++
 7 files changed, 256 insertions(+)
 create mode 100644 pkg/goid/BUILD
 create mode 100644 pkg/goid/empty_test.go
 create mode 100644 pkg/goid/goid.go
 create mode 100644 pkg/goid/goid_amd64.s
 create mode 100644 pkg/goid/goid_race.go
 create mode 100644 pkg/goid/goid_test.go
 create mode 100644 pkg/goid/goid_unsafe.go

diff --git a/pkg/goid/BUILD b/pkg/goid/BUILD
new file mode 100644
index 000000000..5d31e5366
--- /dev/null
+++ b/pkg/goid/BUILD
@@ -0,0 +1,26 @@
+load("//tools/go_stateify:defs.bzl", "go_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_test")
+
+package(licenses = ["notice"])
+
+go_library(
+    name = "goid",
+    srcs = [
+        "goid.go",
+        "goid_amd64.s",
+        "goid_race.go",
+        "goid_unsafe.go",
+    ],
+    importpath = "gvisor.dev/gvisor/pkg/goid",
+    visibility = ["//visibility:public"],
+)
+
+go_test(
+    name = "goid_test",
+    size = "small",
+    srcs = [
+        "empty_test.go",
+        "goid_test.go",
+    ],
+    embed = [":goid"],
+)
diff --git a/pkg/goid/empty_test.go b/pkg/goid/empty_test.go
new file mode 100644
index 000000000..c0a4b17ab
--- /dev/null
+++ b/pkg/goid/empty_test.go
@@ -0,0 +1,22 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !race
+
+package goid
+
+import "testing"
+
+// TestNothing exists to make the build system happy.
+func TestNothing(t *testing.T) {}
diff --git a/pkg/goid/goid.go b/pkg/goid/goid.go
new file mode 100644
index 000000000..39df30031
--- /dev/null
+++ b/pkg/goid/goid.go
@@ -0,0 +1,24 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !race
+
+// Package goid provides access to the ID of the current goroutine in
+// race/gotsan builds.
+package goid
+
+// Get returns the ID of the current goroutine.
+func Get() int64 {
+	panic("unimplemented for non-race builds")
+}
diff --git a/pkg/goid/goid_amd64.s b/pkg/goid/goid_amd64.s
new file mode 100644
index 000000000..d9f5cd2a3
--- /dev/null
+++ b/pkg/goid/goid_amd64.s
@@ -0,0 +1,21 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "textflag.h"
+
+// func getg() *g
+TEXT ·getg(SB),NOSPLIT,$0-8
+	MOVQ (TLS), R14
+	MOVQ R14, ret+0(FP)
+	RET
diff --git a/pkg/goid/goid_race.go b/pkg/goid/goid_race.go
new file mode 100644
index 000000000..1766beaee
--- /dev/null
+++ b/pkg/goid/goid_race.go
@@ -0,0 +1,25 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Only available in race/gotsan builds.
+// +build race
+
+// Package goid provides access to the ID of the current goroutine in
+// race/gotsan builds.
+package goid
+
+// Get returns the ID of the current goroutine.
+func Get() int64 {
+	return goid()
+}
diff --git a/pkg/goid/goid_test.go b/pkg/goid/goid_test.go
new file mode 100644
index 000000000..31970ce79
--- /dev/null
+++ b/pkg/goid/goid_test.go
@@ -0,0 +1,74 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build race
+
+package goid
+
+import (
+	"runtime"
+	"sync"
+	"testing"
+)
+
+func TestInitialGoID(t *testing.T) {
+	const max = 10000
+	if id := goid(); id < 0 || id > max {
+		t.Errorf("got goid = %d, want 0 < goid <= %d", id, max)
+	}
+}
+
+// TestGoIDSquence verifies that goid returns values which could plausibly be
+// goroutine IDs. If this test breaks or becomes flaky, the structs in
+// goid_unsafe.go may need to be updated.
+func TestGoIDSquence(t *testing.T) {
+	// Goroutine IDs are cached by each P.
+	runtime.GOMAXPROCS(1)
+
+	// Fill any holes in lower range.
+	for i := 0; i < 50; i++ {
+		var wg sync.WaitGroup
+		wg.Add(1)
+		go func() {
+			wg.Done()
+
+			// Leak the goroutine to prevent the ID from being
+			// reused.
+			select {}
+		}()
+		wg.Wait()
+	}
+
+	id := goid()
+	for i := 0; i < 100; i++ {
+		var (
+			newID int64
+			wg    sync.WaitGroup
+		)
+		wg.Add(1)
+		go func() {
+			newID = goid()
+			wg.Done()
+
+			// Leak the goroutine to prevent the ID from being
+			// reused.
+			select {}
+		}()
+		wg.Wait()
+		if max := id + 100; newID <= id || newID > max {
+			t.Errorf("unexpected goroutine ID pattern, got goid = %d, want %d < goid <= %d (previous = %d)", newID, id, max, id)
+		}
+		id = newID
+	}
+}
diff --git a/pkg/goid/goid_unsafe.go b/pkg/goid/goid_unsafe.go
new file mode 100644
index 000000000..ded8004dd
--- /dev/null
+++ b/pkg/goid/goid_unsafe.go
@@ -0,0 +1,64 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package goid
+
+// Structs from Go runtime. These may change in the future and require
+// updating. These structs are currently the same on both AMD64 and ARM64,
+// but may diverge in the future.
+
+type stack struct {
+	lo uintptr
+	hi uintptr
+}
+
+type gobuf struct {
+	sp   uintptr
+	pc   uintptr
+	g    uintptr
+	ctxt uintptr
+	ret  uint64
+	lr   uintptr
+	bp   uintptr
+}
+
+type g struct {
+	stack       stack
+	stackguard0 uintptr
+	stackguard1 uintptr
+
+	_panic       uintptr
+	_defer       uintptr
+	m            uintptr
+	sched        gobuf
+	syscallsp    uintptr
+	syscallpc    uintptr
+	stktopsp     uintptr
+	param        uintptr
+	atomicstatus uint32
+	stackLock    uint32
+	goid         int64
+
+	// More fields...
+	//
+	// We only use goid and the fields before it are only listed to
+	// calculate the correct offset.
+}
+
+func getg() *g
+
+// goid returns the ID of the current goroutine.
+func goid() int64 {
+	return getg().goid
+}
-- 
cgit v1.2.3


From bcedf6a8e48b958e39ad7a7dba908354620a0d09 Mon Sep 17 00:00:00 2001
From: Ghanan Gowripalan <ghanan@google.com>
Date: Fri, 10 Jan 2020 14:30:33 -0800
Subject: Put CancellableTimer tests in the tcpip_test package

CancellableTimer tests were in a timer_test package but lived within the
tcpip directory. This caused issues with go tools.

PiperOrigin-RevId: 289166345
---
 pkg/tcpip/BUILD         | 2 +-
 pkg/tcpip/timer_test.go | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/pkg/tcpip/BUILD b/pkg/tcpip/BUILD
index db06d02c6..ebc8d0209 100644
--- a/pkg/tcpip/BUILD
+++ b/pkg/tcpip/BUILD
@@ -30,7 +30,7 @@ go_test(
 )
 
 go_test(
-    name = "timer_test",
+    name = "tcpip_x_test",
     size = "small",
     srcs = ["timer_test.go"],
     deps = [":tcpip"],
diff --git a/pkg/tcpip/timer_test.go b/pkg/tcpip/timer_test.go
index 1f735d735..2d20f7ef3 100644
--- a/pkg/tcpip/timer_test.go
+++ b/pkg/tcpip/timer_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package timer_test
+package tcpip_test
 
 import (
 	"sync"
-- 
cgit v1.2.3


From d27208463e93c01d4e39c0450c3b27c00c466728 Mon Sep 17 00:00:00 2001
From: Ghanan Gowripalan <ghanan@google.com>
Date: Fri, 10 Jan 2020 14:47:08 -0800
Subject: Automated rollback of changelist 288990597

PiperOrigin-RevId: 289169518
---
 pkg/tcpip/stack/BUILD         | 23 ++----------
 pkg/tcpip/stack/ndp_test.go   | 87 ++++---------------------------------------
 pkg/tcpip/stack/stack_test.go | 74 +++++++++++++++++++++++++++++++++---
 3 files changed, 78 insertions(+), 106 deletions(-)

diff --git a/pkg/tcpip/stack/BUILD b/pkg/tcpip/stack/BUILD
index 6a8654105..705e984c1 100644
--- a/pkg/tcpip/stack/BUILD
+++ b/pkg/tcpip/stack/BUILD
@@ -53,6 +53,7 @@ go_test(
     name = "stack_x_test",
     size = "small",
     srcs = [
+        "ndp_test.go",
         "stack_test.go",
         "transport_demuxer_test.go",
         "transport_test.go",
@@ -62,12 +63,14 @@ go_test(
         "//pkg/rand",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
+        "//pkg/tcpip/checker",
         "//pkg/tcpip/header",
         "//pkg/tcpip/iptables",
         "//pkg/tcpip/link/channel",
         "//pkg/tcpip/link/loopback",
         "//pkg/tcpip/network/ipv4",
         "//pkg/tcpip/network/ipv6",
+        "//pkg/tcpip/transport/icmp",
         "//pkg/tcpip/transport/udp",
         "//pkg/waiter",
         "@com_github_google_go-cmp//cmp:go_default_library",
@@ -85,23 +88,3 @@ go_test(
         "//pkg/tcpip",
     ],
 )
-
-go_test(
-    name = "ndp_test",
-    size = "small",
-    srcs = ["ndp_test.go"],
-    deps = [
-        ":stack",
-        "//pkg/rand",
-        "//pkg/tcpip",
-        "//pkg/tcpip/buffer",
-        "//pkg/tcpip/checker",
-        "//pkg/tcpip/header",
-        "//pkg/tcpip/link/channel",
-        "//pkg/tcpip/network/ipv6",
-        "//pkg/tcpip/transport/icmp",
-        "//pkg/tcpip/transport/udp",
-        "//pkg/waiter",
-        "@com_github_google_go-cmp//cmp:go_default_library",
-    ],
-)
diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go
index 108762b6e..f9bc18c55 100644
--- a/pkg/tcpip/stack/ndp_test.go
+++ b/pkg/tcpip/stack/ndp_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ndp_test
+package stack_test
 
 import (
 	"encoding/binary"
@@ -301,8 +301,6 @@ func (n *ndpDispatcher) OnDHCPv6Configuration(nicID tcpip.NICID, configuration s
 // Included in the subtests is a test to make sure that an invalid
 // RetransmitTimer (<1ms) values get fixed to the default RetransmitTimer of 1s.
 func TestDADResolve(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		name                    string
 		dupAddrDetectTransmits  uint8
@@ -435,8 +433,6 @@ func TestDADResolve(t *testing.T) {
 // a node doing DAD for the same address), or if another node is detected to own
 // the address already (receive an NA message for the tentative address).
 func TestDADFail(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		name    string
 		makeBuf func(tgt tcpip.Address) buffer.Prependable
@@ -580,8 +576,6 @@ func TestDADFail(t *testing.T) {
 // TestDADStop tests to make sure that the DAD process stops when an address is
 // removed.
 func TestDADStop(t *testing.T) {
-	t.Parallel()
-
 	ndpDisp := ndpDispatcher{
 		dadC: make(chan ndpDADEvent),
 	}
@@ -654,71 +648,6 @@ func TestDADStop(t *testing.T) {
 	}
 }
 
-// TestNICAutoGenAddrDoesDAD tests that the successful auto-generation of IPv6
-// link-local addresses will only be assigned after the DAD process resolves.
-func TestNICAutoGenAddrDoesDAD(t *testing.T) {
-	t.Parallel()
-
-	ndpDisp := ndpDispatcher{
-		dadC: make(chan ndpDADEvent),
-	}
-	ndpConfigs := stack.DefaultNDPConfigurations()
-	opts := stack.Options{
-		NetworkProtocols:     []stack.NetworkProtocol{ipv6.NewProtocol()},
-		NDPConfigs:           ndpConfigs,
-		AutoGenIPv6LinkLocal: true,
-		NDPDisp:              &ndpDisp,
-	}
-
-	e := channel.New(0, 1280, linkAddr1)
-	s := stack.New(opts)
-	if err := s.CreateNIC(1, e); err != nil {
-		t.Fatalf("CreateNIC(_) = %s", err)
-	}
-
-	// Address should not be considered bound to the
-	// NIC yet (DAD ongoing).
-	addr, err := s.GetMainNICAddress(1, header.IPv6ProtocolNumber)
-	if err != nil {
-		t.Fatalf("got stack.GetMainNICAddress(_, _) = (_, %v), want = (_, nil)", err)
-	}
-	if want := (tcpip.AddressWithPrefix{}); addr != want {
-		t.Fatalf("got stack.GetMainNICAddress(_, _) = (%s, nil), want = (%s, nil)", addr, want)
-	}
-
-	linkLocalAddr := header.LinkLocalAddr(linkAddr1)
-
-	// Wait for DAD to resolve.
-	select {
-	case <-time.After(time.Duration(ndpConfigs.DupAddrDetectTransmits)*ndpConfigs.RetransmitTimer + time.Second):
-		// We should get a resolution event after 1s (default time to
-		// resolve as per default NDP configurations). Waiting for that
-		// resolution time + an extra 1s without a resolution event
-		// means something is wrong.
-		t.Fatal("timed out waiting for DAD resolution")
-	case e := <-ndpDisp.dadC:
-		if e.err != nil {
-			t.Fatal("got DAD error: ", e.err)
-		}
-		if e.nicID != 1 {
-			t.Fatalf("got DAD event w/ nicID = %d, want = 1", e.nicID)
-		}
-		if e.addr != linkLocalAddr {
-			t.Fatalf("got DAD event w/ addr = %s, want = %s", addr, linkLocalAddr)
-		}
-		if !e.resolved {
-			t.Fatal("got DAD event w/ resolved = false, want = true")
-		}
-	}
-	addr, err = s.GetMainNICAddress(1, header.IPv6ProtocolNumber)
-	if err != nil {
-		t.Fatalf("stack.GetMainNICAddress(_, _) err = %s", err)
-	}
-	if want := (tcpip.AddressWithPrefix{Address: linkLocalAddr, PrefixLen: header.IPv6LinkLocalPrefix.PrefixLen}); addr != want {
-		t.Fatalf("got stack.GetMainNICAddress(_, _) = %s, want = %s", addr, want)
-	}
-}
-
 // TestSetNDPConfigurationFailsForBadNICID tests to make sure we get an error if
 // we attempt to update NDP configurations using an invalid NICID.
 func TestSetNDPConfigurationFailsForBadNICID(t *testing.T) {
@@ -736,8 +665,6 @@ func TestSetNDPConfigurationFailsForBadNICID(t *testing.T) {
 // configurations without affecting the default NDP configurations or other
 // interfaces' configurations.
 func TestSetNDPConfigurations(t *testing.T) {
-	t.Parallel()
-
 	tests := []struct {
 		name                    string
 		dupAddrDetectTransmits  uint8
@@ -992,8 +919,6 @@ func raBufWithPI(ip tcpip.Address, rl uint16, prefix tcpip.AddressWithPrefix, on
 // TestNoRouterDiscovery tests that router discovery will not be performed if
 // configured not to.
 func TestNoRouterDiscovery(t *testing.T) {
-	t.Parallel()
-
 	// Being configured to discover routers means handle and
 	// discover are set to true and forwarding is set to false.
 	// This tests all possible combinations of the configurations,
@@ -1006,6 +931,8 @@ func TestNoRouterDiscovery(t *testing.T) {
 		forwarding := i&4 == 0
 
 		t.Run(fmt.Sprintf("HandleRAs(%t), DiscoverDefaultRouters(%t), Forwarding(%t)", handle, discover, forwarding), func(t *testing.T) {
+			t.Parallel()
+
 			ndpDisp := ndpDispatcher{
 				routerC: make(chan ndpRouterEvent, 1),
 			}
@@ -1240,8 +1167,6 @@ func TestRouterDiscoveryMaxRouters(t *testing.T) {
 // TestNoPrefixDiscovery tests that prefix discovery will not be performed if
 // configured not to.
 func TestNoPrefixDiscovery(t *testing.T) {
-	t.Parallel()
-
 	prefix := tcpip.AddressWithPrefix{
 		Address:   tcpip.Address("\x01\x02\x03\x04\x05\x06\x07\x08\x00\x00\x00\x00\x00\x00\x00\x00"),
 		PrefixLen: 64,
@@ -1259,6 +1184,8 @@ func TestNoPrefixDiscovery(t *testing.T) {
 		forwarding := i&4 == 0
 
 		t.Run(fmt.Sprintf("HandleRAs(%t), DiscoverOnLinkPrefixes(%t), Forwarding(%t)", handle, discover, forwarding), func(t *testing.T) {
+			t.Parallel()
+
 			ndpDisp := ndpDispatcher{
 				prefixC: make(chan ndpPrefixEvent, 1),
 			}
@@ -1615,8 +1542,6 @@ func contains(list []tcpip.ProtocolAddress, item tcpip.AddressWithPrefix) bool {
 
 // TestNoAutoGenAddr tests that SLAAC is not performed when configured not to.
 func TestNoAutoGenAddr(t *testing.T) {
-	t.Parallel()
-
 	prefix, _, _ := prefixSubnetAddr(0, "")
 
 	// Being configured to auto-generate addresses means handle and
@@ -1631,6 +1556,8 @@ func TestNoAutoGenAddr(t *testing.T) {
 		forwarding := i&4 == 0
 
 		t.Run(fmt.Sprintf("HandleRAs(%t), AutoGenAddr(%t), Forwarding(%t)", handle, autogen, forwarding), func(t *testing.T) {
+			t.Parallel()
+
 			ndpDisp := ndpDispatcher{
 				autoGenAddrC: make(chan ndpAutoGenAddrEvent, 1),
 			}
diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go
index e8de4e87d..44e5229cc 100644
--- a/pkg/tcpip/stack/stack_test.go
+++ b/pkg/tcpip/stack/stack_test.go
@@ -24,6 +24,7 @@ import (
 	"sort"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/google/go-cmp/cmp"
 	"gvisor.dev/gvisor/pkg/rand"
@@ -49,8 +50,6 @@ const (
 	// where another value is explicitly used. It is chosen to match the MTU
 	// of loopback interfaces on linux systems.
 	defaultMTU = 65536
-
-	linkAddr = "\x02\x02\x03\x04\x05\x06"
 )
 
 // fakeNetworkEndpoint is a network-layer protocol endpoint. It counts sent and
@@ -1910,7 +1909,7 @@ func TestNICAutoGenAddr(t *testing.T) {
 		{
 			"Disabled",
 			false,
-			linkAddr,
+			linkAddr1,
 			stack.OpaqueInterfaceIdentifierOptions{
 				NICNameFromID: func(nicID tcpip.NICID, _ string) string {
 					return fmt.Sprintf("nic%d", nicID)
@@ -1921,7 +1920,7 @@ func TestNICAutoGenAddr(t *testing.T) {
 		{
 			"Enabled",
 			true,
-			linkAddr,
+			linkAddr1,
 			stack.OpaqueInterfaceIdentifierOptions{},
 			true,
 		},
@@ -2069,14 +2068,14 @@ func TestNICAutoGenAddrWithOpaque(t *testing.T) {
 			name:      "Disabled",
 			nicName:   "nic1",
 			autoGen:   false,
-			linkAddr:  linkAddr,
+			linkAddr:  linkAddr1,
 			secretKey: secretKey[:],
 		},
 		{
 			name:      "Enabled",
 			nicName:   "nic1",
 			autoGen:   true,
-			linkAddr:  linkAddr,
+			linkAddr:  linkAddr1,
 			secretKey: secretKey[:],
 		},
 		// These are all cases where we would not have generated a
@@ -2214,6 +2213,69 @@ func TestNoLinkLocalAutoGenForLoopbackNIC(t *testing.T) {
 	}
 }
 
+// TestNICAutoGenAddrDoesDAD tests that the successful auto-generation of IPv6
+// link-local addresses will only be assigned after the DAD process resolves.
+func TestNICAutoGenAddrDoesDAD(t *testing.T) {
+	ndpDisp := ndpDispatcher{
+		dadC: make(chan ndpDADEvent),
+	}
+	ndpConfigs := stack.DefaultNDPConfigurations()
+	opts := stack.Options{
+		NetworkProtocols:     []stack.NetworkProtocol{ipv6.NewProtocol()},
+		NDPConfigs:           ndpConfigs,
+		AutoGenIPv6LinkLocal: true,
+		NDPDisp:              &ndpDisp,
+	}
+
+	e := channel.New(10, 1280, linkAddr1)
+	s := stack.New(opts)
+	if err := s.CreateNIC(1, e); err != nil {
+		t.Fatalf("CreateNIC(_) = %s", err)
+	}
+
+	// Address should not be considered bound to the
+	// NIC yet (DAD ongoing).
+	addr, err := s.GetMainNICAddress(1, header.IPv6ProtocolNumber)
+	if err != nil {
+		t.Fatalf("got stack.GetMainNICAddress(_, _) = (_, %v), want = (_, nil)", err)
+	}
+	if want := (tcpip.AddressWithPrefix{}); addr != want {
+		t.Fatalf("got stack.GetMainNICAddress(_, _) = (%s, nil), want = (%s, nil)", addr, want)
+	}
+
+	linkLocalAddr := header.LinkLocalAddr(linkAddr1)
+
+	// Wait for DAD to resolve.
+	select {
+	case <-time.After(time.Duration(ndpConfigs.DupAddrDetectTransmits)*ndpConfigs.RetransmitTimer + time.Second):
+		// We should get a resolution event after 1s (default time to
+		// resolve as per default NDP configurations). Waiting for that
+		// resolution time + an extra 1s without a resolution event
+		// means something is wrong.
+		t.Fatal("timed out waiting for DAD resolution")
+	case e := <-ndpDisp.dadC:
+		if e.err != nil {
+			t.Fatal("got DAD error: ", e.err)
+		}
+		if e.nicID != 1 {
+			t.Fatalf("got DAD event w/ nicID = %d, want = 1", e.nicID)
+		}
+		if e.addr != linkLocalAddr {
+			t.Fatalf("got DAD event w/ addr = %s, want = %s", addr, linkLocalAddr)
+		}
+		if !e.resolved {
+			t.Fatal("got DAD event w/ resolved = false, want = true")
+		}
+	}
+	addr, err = s.GetMainNICAddress(1, header.IPv6ProtocolNumber)
+	if err != nil {
+		t.Fatalf("stack.GetMainNICAddress(_, _) err = %s", err)
+	}
+	if want := (tcpip.AddressWithPrefix{Address: linkLocalAddr, PrefixLen: header.IPv6LinkLocalPrefix.PrefixLen}); addr != want {
+		t.Fatalf("got stack.GetMainNICAddress(_, _) = %s, want = %s", addr, want)
+	}
+}
+
 // TestNewPEB tests that a new PrimaryEndpointBehavior value (peb) is respected
 // when an address's kind gets "promoted" to permanent from permanentExpired.
 func TestNewPEBOnPromotionToPermanent(t *testing.T) {
-- 
cgit v1.2.3


From bf6429b944aed6de073c62ceb446cfaed5042dbc Mon Sep 17 00:00:00 2001
From: Brad Burlage <brb@google.com>
Date: Fri, 10 Jan 2020 16:34:59 -0800
Subject: Don't set RWF_HIPRI on InvalidOffset test.

This test fails on ubuntu 18.04 because preadv2 for some reason returns
EOPNOTSUPP instead of EINVAL. Instead of root-causing the failure, I'm dropping
the flag in the preadv2 call since it isn't under test in this scenario.

PiperOrigin-RevId: 289188358
---
 test/syscalls/linux/preadv2.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/syscalls/linux/preadv2.cc b/test/syscalls/linux/preadv2.cc
index c9246367d..cd936ea90 100644
--- a/test/syscalls/linux/preadv2.cc
+++ b/test/syscalls/linux/preadv2.cc
@@ -202,7 +202,7 @@ TEST(Preadv2Test, TestInvalidOffset) {
   iov[0].iov_len = 0;
 
   EXPECT_THAT(preadv2(fd.get(), iov.get(), /*iovcnt=*/1, /*offset=*/-8,
-                      /*flags=*/RWF_HIPRI),
+                      /*flags=*/0),
               SyscallFailsWithErrno(EINVAL));
 }
 
-- 
cgit v1.2.3


From f54b9c0ee6e02f9c8bf32aa268c9028ff741bf7c Mon Sep 17 00:00:00 2001
From: Andrei Vagin <avagin@google.com>
Date: Mon, 13 Jan 2020 10:14:30 -0800
Subject: tests: fix errors detected by asan.

PiperOrigin-RevId: 289467083
---
 test/syscalls/linux/inotify.cc      | 4 ++--
 test/syscalls/linux/poll.cc         | 3 ++-
 test/syscalls/linux/readv_common.cc | 2 +-
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/test/syscalls/linux/inotify.cc b/test/syscalls/linux/inotify.cc
index 59ec9940a..fdef646eb 100644
--- a/test/syscalls/linux/inotify.cc
+++ b/test/syscalls/linux/inotify.cc
@@ -977,7 +977,7 @@ TEST(Inotify, WatchOnRelativePath) {
       ASSERT_NO_ERRNO_AND_VALUE(Open(file1.path(), O_RDONLY));
 
   // Change working directory to root.
-  const char* old_working_dir = get_current_dir_name();
+  const FileDescriptor cwd = ASSERT_NO_ERRNO_AND_VALUE(Open(".", O_PATH));
   EXPECT_THAT(chdir(root.path().c_str()), SyscallSucceeds());
 
   // Add a watch on file1 with a relative path.
@@ -997,7 +997,7 @@ TEST(Inotify, WatchOnRelativePath) {
   // continue to hold a reference, random save/restore tests can fail if a save
   // is triggered after "root" is unlinked; we can't save deleted fs objects
   // with active references.
-  EXPECT_THAT(chdir(old_working_dir), SyscallSucceeds());
+  EXPECT_THAT(fchdir(cwd.get()), SyscallSucceeds());
 }
 
 TEST(Inotify, ZeroLengthReadWriteDoesNotGenerateEvent) {
diff --git a/test/syscalls/linux/poll.cc b/test/syscalls/linux/poll.cc
index 9e5aa7fd0..c42472474 100644
--- a/test/syscalls/linux/poll.cc
+++ b/test/syscalls/linux/poll.cc
@@ -275,7 +275,8 @@ TEST_F(PollTest, Nfds) {
   // Each entry in the 'fds' array refers to the eventfd and polls for
   // "writable" events (events=POLLOUT). This essentially guarantees that the
   // poll() is a no-op and allows negative testing of the 'nfds' parameter.
-  std::vector<struct pollfd> fds(max_fds, {.fd = efd.get(), .events = POLLOUT});
+  std::vector<struct pollfd> fds(max_fds + 1,
+                                 {.fd = efd.get(), .events = POLLOUT});
 
   // Verify that 'nfds' up to RLIMIT_NOFILE are allowed.
   EXPECT_THAT(RetryEINTR(poll)(fds.data(), 1, 1), SyscallSucceedsWithValue(1));
diff --git a/test/syscalls/linux/readv_common.cc b/test/syscalls/linux/readv_common.cc
index 491d5f40f..2694dc64f 100644
--- a/test/syscalls/linux/readv_common.cc
+++ b/test/syscalls/linux/readv_common.cc
@@ -154,7 +154,7 @@ void ReadBuffersOverlapping(int fd) {
   char* expected_ptr = expected.data();
   memcpy(expected_ptr, &kReadvTestData[overlap_bytes], overlap_bytes);
   memcpy(&expected_ptr[overlap_bytes], &kReadvTestData[overlap_bytes],
-         kReadvTestDataSize);
+         kReadvTestDataSize - overlap_bytes);
 
   struct iovec iovs[2];
   iovs[0].iov_base = buffer.data();
-- 
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