Do not copy sleep.Waker

sleep.Waker's fields are modified as values.

PiperOrigin-RevId: 320873451

2 files changed, 29 insertions, 0 deletions

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() {}