diff options
author | Ghanan Gowripalan <ghanan@google.com> | 2020-07-12 17:20:50 -0700 |
---|---|---|
committer | gVisor bot <gvisor-bot@google.com> | 2020-07-12 17:22:08 -0700 |
commit | 9c32fd3f4d8f6e63d922c1c58b7d1f1f504fa2bc (patch) | |
tree | dfb5150ec211a268f9f69bfc22d0ba3ecf0795dc | |
parent | 69f2059e5d38bacac4bcda7912cca580ab70914d (diff) |
Do not copy sleep.Waker
sleep.Waker's fields are modified as values.
PiperOrigin-RevId: 320873451
-rw-r--r-- | pkg/sleep/BUILD | 1 | ||||
-rw-r--r-- | pkg/sleep/sleep_test.go | 20 | ||||
-rw-r--r-- | pkg/sleep/sleep_unsafe.go | 7 | ||||
-rw-r--r-- | pkg/sync/BUILD | 1 | ||||
-rw-r--r-- | pkg/sync/nocopy.go | 28 | ||||
-rw-r--r-- | pkg/tcpip/stack/packet_buffer.go | 14 | ||||
-rw-r--r-- | pkg/tcpip/timer.go | 21 |
7 files changed, 50 insertions, 42 deletions
diff --git a/pkg/sleep/BUILD b/pkg/sleep/BUILD index e131455f7..ae0fe1522 100644 --- a/pkg/sleep/BUILD +++ b/pkg/sleep/BUILD @@ -12,6 +12,7 @@ go_library( "sleep_unsafe.go", ], visibility = ["//:sandbox"], + deps = ["//pkg/sync"], ) go_test( diff --git a/pkg/sleep/sleep_test.go b/pkg/sleep/sleep_test.go index af47e2ba1..1dd11707d 100644 --- a/pkg/sleep/sleep_test.go +++ b/pkg/sleep/sleep_test.go @@ -379,10 +379,7 @@ func TestRace(t *testing.T) { // TestRaceInOrder tests that multiple wakers can continuously send wake requests to // the sleeper and that the wakers are retrieved in the order asserted. func TestRaceInOrder(t *testing.T) { - const wakers = 100 - const wakeRequests = 10000 - - w := make([]Waker, wakers) + w := make([]Waker, 10000) s := Sleeper{} // Associate each waker and start goroutines that will assert them. @@ -390,19 +387,16 @@ func TestRaceInOrder(t *testing.T) { s.AddWaker(&w[i], i) } go func() { - n := 0 - for n < wakeRequests { - wk := w[n%len(w)] - wk.Assert() - n++ + for i := range w { + w[i].Assert() } }() // Wait for all wake up notifications from all wakers. - for i := 0; i < wakeRequests; i++ { - v, _ := s.Fetch(true) - if got, want := v, i%wakers; got != want { - t.Fatalf("got %d want %d", got, want) + for want := range w { + got, _ := s.Fetch(true) + if got != want { + t.Fatalf("got %d want %d", got, want) } } } diff --git a/pkg/sleep/sleep_unsafe.go b/pkg/sleep/sleep_unsafe.go index f68c12620..118805492 100644 --- a/pkg/sleep/sleep_unsafe.go +++ b/pkg/sleep/sleep_unsafe.go @@ -75,6 +75,8 @@ package sleep import ( "sync/atomic" "unsafe" + + "gvisor.dev/gvisor/pkg/sync" ) const ( @@ -323,7 +325,12 @@ func (s *Sleeper) enqueueAssertedWaker(w *Waker) { // // This struct is thread-safe, that is, its methods can be called concurrently // by multiple goroutines. +// +// Note, it is not safe to copy a Waker as its fields are modified by value +// (the pointer fields are individually modified with atomic operations). type Waker struct { + _ sync.NoCopy + // s is the sleeper that this waker can wake up. Only one sleeper at a // time is allowed. This field can have three classes of values: // nil -- the waker is not asserted: it either is not associated with diff --git a/pkg/sync/BUILD b/pkg/sync/BUILD index d0d77e19c..4d47207f7 100644 --- a/pkg/sync/BUILD +++ b/pkg/sync/BUILD @@ -33,6 +33,7 @@ go_library( "aliases.go", "memmove_unsafe.go", "mutex_unsafe.go", + "nocopy.go", "norace_unsafe.go", "race_unsafe.go", "rwmutex_unsafe.go", diff --git a/pkg/sync/nocopy.go b/pkg/sync/nocopy.go new file mode 100644 index 000000000..722b29501 --- /dev/null +++ b/pkg/sync/nocopy.go @@ -0,0 +1,28 @@ +// 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 sync + +// NoCopy may be embedded into structs which must not be copied +// after the first use. +// +// See https://golang.org/issues/8005#issuecomment-190753527 +// for details. +type NoCopy struct{} + +// Lock is a no-op used by -copylocks checker from `go vet`. +func (*NoCopy) Lock() {} + +// Unlock is a no-op used by -copylocks checker from `go vet`. +func (*NoCopy) Unlock() {} diff --git a/pkg/tcpip/stack/packet_buffer.go b/pkg/tcpip/stack/packet_buffer.go index 1b5da6017..e3556d5d2 100644 --- a/pkg/tcpip/stack/packet_buffer.go +++ b/pkg/tcpip/stack/packet_buffer.go @@ -14,6 +14,7 @@ package stack import ( + "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/tcpip/buffer" ) @@ -24,7 +25,7 @@ import ( // multiple endpoints. Clone() should be called in such cases so that // modifications to the Data field do not affect other copies. type PacketBuffer struct { - _ noCopy + _ sync.NoCopy // PacketBufferEntry is used to build an intrusive list of // PacketBuffers. @@ -102,14 +103,3 @@ func (pk *PacketBuffer) Clone() *PacketBuffer { NatDone: pk.NatDone, } } - -// noCopy may be embedded into structs which must not be copied -// after the first use. -// -// See https://golang.org/issues/8005#issuecomment-190753527 -// for details. -type noCopy struct{} - -// Lock is a no-op used by -copylocks checker from `go vet`. -func (*noCopy) Lock() {} -func (*noCopy) Unlock() {} diff --git a/pkg/tcpip/timer.go b/pkg/tcpip/timer.go index 59f3b391f..5554c573f 100644 --- a/pkg/tcpip/timer.go +++ b/pkg/tcpip/timer.go @@ -15,8 +15,9 @@ package tcpip import ( - "sync" "time" + + "gvisor.dev/gvisor/pkg/sync" ) // cancellableTimerInstance is a specific instance of CancellableTimer. @@ -92,6 +93,8 @@ func (t *cancellableTimerInstance) stop() { // Note, it is not safe to copy a CancellableTimer as its timer instance creates // a closure over the address of the CancellableTimer. type CancellableTimer struct { + _ sync.NoCopy + // The active instance of a cancellable timer. instance cancellableTimerInstance @@ -157,22 +160,6 @@ func (t *CancellableTimer) Reset(d time.Duration) { } } -// Lock is a no-op used by the copylocks checker from go vet. -// -// See CancellableTimer for details about why it shouldn't be copied. -// -// See https://github.com/golang/go/issues/8005#issuecomment-190753527 for more -// details about the copylocks checker. -func (*CancellableTimer) Lock() {} - -// Unlock is a no-op used by the copylocks checker from go vet. -// -// See CancellableTimer for details about why it shouldn't be copied. -// -// See https://github.com/golang/go/issues/8005#issuecomment-190753527 for more -// details about the copylocks checker. -func (*CancellableTimer) Unlock() {} - // NewCancellableTimer returns an unscheduled CancellableTimer with the given // locker and fn. // |