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

16 files changed, 19 insertions, 12 deletions

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.