Merge release-20191213.0-96-g27500d5 (automated)

148 files changed, 223 insertions, 206 deletions

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/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/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/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/flipcall_unsafe.go b/pkg/flipcall/flipcall_unsafe.go
index 27b8939fc..ac974b232 100755
--- 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/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/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/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/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/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/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/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/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/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/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/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/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/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/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/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/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/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/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/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/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/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/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/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/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/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/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/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/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/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/memory_events.go b/pkg/sentry/kernel/memevent/memory_events.go
index b0d98e7f0..200565bb8 100755
--- 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/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 100755
--- 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 100755
--- 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/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/seqatomic_taskgoroutineschedinfo_unsafe.go b/pkg/sentry/kernel/seqatomic_taskgoroutineschedinfo_unsafe.go
index 11e820656..51d4d55f8 100755
--- a/pkg/sentry/kernel/seqatomic_taskgoroutineschedinfo_unsafe.go
+++ b/pkg/sentry/kernel/seqatomic_taskgoroutineschedinfo_unsafe.go
@@ -1,25 +1,24 @@
 package kernel
 
 import (
-	"strings"
-	"unsafe"
-
 	"fmt"
-	"gvisor.dev/gvisor/pkg/syncutil"
+	"gvisor.dev/gvisor/pkg/sync"
 	"reflect"
+	"strings"
+	"unsafe"
 )
 
 // SeqAtomicLoad returns a copy of *ptr, ensuring that the read does not race
 // with any writer critical sections in sc.
-func SeqAtomicLoadTaskGoroutineSchedInfo(sc *syncutil.SeqCount, ptr *TaskGoroutineSchedInfo) TaskGoroutineSchedInfo {
+func SeqAtomicLoadTaskGoroutineSchedInfo(sc *sync.SeqCount, ptr *TaskGoroutineSchedInfo) TaskGoroutineSchedInfo {
 	// This function doesn't use SeqAtomicTryLoad because doing so is
 	// measurably, significantly (~20%) slower; Go is awful at inlining.
 	var val TaskGoroutineSchedInfo
 	for {
 		epoch := sc.BeginRead()
-		if syncutil.RaceEnabled {
+		if sync.RaceEnabled {
 
-			syncutil.Memmove(unsafe.Pointer(&val), unsafe.Pointer(ptr), unsafe.Sizeof(val))
+			sync.Memmove(unsafe.Pointer(&val), unsafe.Pointer(ptr), unsafe.Sizeof(val))
 		} else {
 
 			val = *ptr
@@ -35,10 +34,10 @@ func SeqAtomicLoadTaskGoroutineSchedInfo(sc *syncutil.SeqCount, ptr *TaskGorouti
 // 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 SeqAtomicTryLoadTaskGoroutineSchedInfo(sc *syncutil.SeqCount, epoch syncutil.SeqCountEpoch, ptr *TaskGoroutineSchedInfo) (TaskGoroutineSchedInfo, bool) {
+func SeqAtomicTryLoadTaskGoroutineSchedInfo(sc *sync.SeqCount, epoch sync.SeqCountEpoch, ptr *TaskGoroutineSchedInfo) (TaskGoroutineSchedInfo, bool) {
 	var val TaskGoroutineSchedInfo
-	if syncutil.RaceEnabled {
-		syncutil.Memmove(unsafe.Pointer(&val), unsafe.Pointer(ptr), unsafe.Sizeof(val))
+	if sync.RaceEnabled {
+		sync.Memmove(unsafe.Pointer(&val), unsafe.Pointer(ptr), unsafe.Sizeof(val))
 	} else {
 		val = *ptr
 	}
@@ -49,7 +48,7 @@ func initTaskGoroutineSchedInfo() {
 	var val TaskGoroutineSchedInfo
 	typ := reflect.TypeOf(val)
 	name := typ.Name()
-	if ptrs := syncutil.PointersInType(typ, name); len(ptrs) != 0 {
+	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/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/signalfd.go b/pkg/sentry/kernel/signalfd/signalfd.go
index 4b08d7d72..28be4a939 100755
--- 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/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 100755
--- 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/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/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/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/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/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 100755
--- 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/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_impl_amd64.go b/pkg/sentry/platform/ring0/defs_impl_amd64.go
index 73404a116..b9839d9b1 100755
--- a/pkg/sentry/platform/ring0/defs_impl_amd64.go
+++ b/pkg/sentry/platform/ring0/defs_impl_amd64.go
@@ -1,14 +1,14 @@
 package ring0
 
 import (
+	"fmt"
 	"gvisor.dev/gvisor/pkg/cpuid"
+	"io"
 	"reflect"
 	"syscall"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
-	"io"
 )
 
 // Kernel is a global kernel object.
diff --git a/pkg/sentry/platform/ring0/defs_impl_arm64.go b/pkg/sentry/platform/ring0/defs_impl_arm64.go
index 5c3bb430c..4f7fd3b01 100755
--- a/pkg/sentry/platform/ring0/defs_impl_arm64.go
+++ b/pkg/sentry/platform/ring0/defs_impl_arm64.go
@@ -1,13 +1,13 @@
 package ring0
 
 import (
+	"fmt"
+	"io"
+	"reflect"
 	"syscall"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
-	"io"
-	"reflect"
 )
 
 // Useful bits.
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/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/netstack.go b/pkg/sentry/socket/netstack/netstack.go
index 764f11a6b..0affb8071 100755
--- 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/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/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/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/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/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/time/seqatomic_parameters_unsafe.go b/pkg/sentry/time/seqatomic_parameters_unsafe.go
index e3c134e49..32820e9ba 100755
--- a/pkg/sentry/time/seqatomic_parameters_unsafe.go
+++ b/pkg/sentry/time/seqatomic_parameters_unsafe.go
@@ -1,25 +1,24 @@
 package time
 
 import (
-	"strings"
-	"unsafe"
-
 	"fmt"
-	"gvisor.dev/gvisor/pkg/syncutil"
+	"gvisor.dev/gvisor/pkg/sync"
 	"reflect"
+	"strings"
+	"unsafe"
 )
 
 // SeqAtomicLoad returns a copy of *ptr, ensuring that the read does not race
 // with any writer critical sections in sc.
-func SeqAtomicLoadParameters(sc *syncutil.SeqCount, ptr *Parameters) Parameters {
+func SeqAtomicLoadParameters(sc *sync.SeqCount, ptr *Parameters) Parameters {
 	// This function doesn't use SeqAtomicTryLoad because doing so is
 	// measurably, significantly (~20%) slower; Go is awful at inlining.
 	var val Parameters
 	for {
 		epoch := sc.BeginRead()
-		if syncutil.RaceEnabled {
+		if sync.RaceEnabled {
 
-			syncutil.Memmove(unsafe.Pointer(&val), unsafe.Pointer(ptr), unsafe.Sizeof(val))
+			sync.Memmove(unsafe.Pointer(&val), unsafe.Pointer(ptr), unsafe.Sizeof(val))
 		} else {
 
 			val = *ptr
@@ -35,10 +34,10 @@ func SeqAtomicLoadParameters(sc *syncutil.SeqCount, ptr *Parameters) Parameters
 // 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 SeqAtomicTryLoadParameters(sc *syncutil.SeqCount, epoch syncutil.SeqCountEpoch, ptr *Parameters) (Parameters, bool) {
+func SeqAtomicTryLoadParameters(sc *sync.SeqCount, epoch sync.SeqCountEpoch, ptr *Parameters) (Parameters, bool) {
 	var val Parameters
-	if syncutil.RaceEnabled {
-		syncutil.Memmove(unsafe.Pointer(&val), unsafe.Pointer(ptr), unsafe.Sizeof(val))
+	if sync.RaceEnabled {
+		sync.Memmove(unsafe.Pointer(&val), unsafe.Pointer(ptr), unsafe.Sizeof(val))
 	} else {
 		val = *ptr
 	}
@@ -49,7 +48,7 @@ func initParameters() {
 	var val Parameters
 	typ := reflect.TypeOf(val)
 	name := typ.Name()
-	if ptrs := syncutil.PointersInType(typ, name); len(ptrs) != 0 {
+	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/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/dentry.go b/pkg/sentry/vfs/dentry.go
index 1bc9c4a38..486a76475 100755
--- 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 100755
--- 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_unsafe.go b/pkg/sentry/vfs/mount_unsafe.go
index ab13fa461..bd90d36c4 100755
--- 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 100755
--- 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 100755
--- 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 100755
--- 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/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/aliases.go b/pkg/sync/aliases.go
new file mode 100755
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/syncutil/downgradable_rwmutex_unsafe.go b/pkg/sync/downgradable_rwmutex_unsafe.go
index 51e11555d..9bb55cd3a 100755
--- a/pkg/syncutil/downgradable_rwmutex_unsafe.go
+++ b/pkg/sync/downgradable_rwmutex_unsafe.go
@@ -16,7 +16,7 @@
 // - RUnlock -> Lock (via writerSem)
 // - DowngradeLock -> RLock (via readerSem)
 
-package syncutil
+package sync
 
 import (
 	"sync"
diff --git a/pkg/syncutil/memmove_unsafe.go b/pkg/sync/memmove_unsafe.go
index 348675baa..ad4a3a37e 100755
--- a/pkg/syncutil/memmove_unsafe.go
+++ b/pkg/sync/memmove_unsafe.go
@@ -8,7 +8,7 @@
 
 // Check go:linkname function signatures when updating Go version.
 
-package syncutil
+package sync
 
 import (
 	"unsafe"
diff --git a/pkg/syncutil/norace_unsafe.go b/pkg/sync/norace_unsafe.go
index 0a0a9deda..006055dd6 100755
--- a/pkg/syncutil/norace_unsafe.go
+++ b/pkg/sync/norace_unsafe.go
@@ -5,7 +5,7 @@
 
 // +build !race
 
-package syncutil
+package sync
 
 import (
 	"unsafe"
diff --git a/pkg/syncutil/race_unsafe.go b/pkg/sync/race_unsafe.go
index 206067ec1..31d8fa9a6 100755
--- a/pkg/syncutil/race_unsafe.go
+++ b/pkg/sync/race_unsafe.go
@@ -5,7 +5,7 @@
 
 // +build race
 
-package syncutil
+package sync
 
 import (
 	"runtime"
diff --git a/pkg/syncutil/seqcount.go b/pkg/sync/seqcount.go
index 11d8dbfaa..a1e895352 100755
--- a/pkg/syncutil/seqcount.go
+++ b/pkg/sync/seqcount.go
@@ -3,7 +3,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package syncutil
+package sync
 
 import (
 	"fmt"
diff --git a/pkg/syncutil/syncutil_state_autogen.go b/pkg/sync/sync_state_autogen.go
index f46e00edf..b2872d33d 100755
--- a/pkg/syncutil/syncutil_state_autogen.go
+++ b/pkg/sync/sync_state_autogen.go
@@ -1,4 +1,4 @@
 // automatically generated by stateify.
 
-package syncutil
+package sync
 
diff --git a/pkg/syncutil/syncutil.go b/pkg/sync/syncutil.go
index 66e750d06..b16cf5333 100755
--- a/pkg/syncutil/syncutil.go
+++ b/pkg/sync/syncutil.go
@@ -3,5 +3,5 @@
 // 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
+// Package sync provides synchronization primitives.
+package sync
diff --git a/pkg/tcpip/adapters/gonet/gonet.go b/pkg/tcpip/adapters/gonet/gonet.go
index cd6ce930a..a2f44b496 100755
--- 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/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/sharedmem.go b/pkg/tcpip/link/sharedmem/sharedmem.go
index 080f9d667..655e537c4 100755
--- 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/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/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/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/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/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/endpoint.go b/pkg/tcpip/transport/packet/endpoint.go
index 07ffa8aba..fc5bc69fa 100755
--- 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/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/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/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/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/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.