diff options
| author | Nicolas Lacasse <nlacasse@google.com> | 2019-07-31 11:59:21 -0700 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2019-07-31 12:00:35 -0700 |
| commit | cf2b2d97d512a91261f72abe40b163c61d52705f (patch) | |
| tree | 92950786ab5093509df999ef8f75af00676d0eda | |
| parent | edcc60b931232d5bea4254af31965da126f07a68 (diff) | |
Initialize kernel.unimplementedSyscallEmitter with a sync.Once.
This is initialized lazily on the first unimplemented
syscall. Without the sync.Once, this is racy.
PiperOrigin-RevId: 260971758
| -rw-r--r-- | pkg/sentry/kernel/kernel.go | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/pkg/sentry/kernel/kernel.go b/pkg/sentry/kernel/kernel.go index 55a9d3d29..53c25e49e 100644 --- a/pkg/sentry/kernel/kernel.go +++ b/pkg/sentry/kernel/kernel.go @@ -198,6 +198,10 @@ type Kernel struct { // the limiter. It may be nil if disabled. DirentCacheLimiter *fs.DirentCacheLimiter + // unimplementedSyscallEmitterOnce is used in the initialization of + // unimplementedSyscallEmitter. + unimplementedSyscallEmitterOnce sync.Once `state:"nosave"` + // unimplementedSyscallEmitter is used to emit unimplemented syscall // events. This is initialized lazily on the first unimplemented // syscall. @@ -1283,7 +1287,7 @@ func (ctx supervisorContext) Value(key interface{}) interface{} { } } -// Rate limits for the number of unimplemented syscall evants. +// Rate limits for the number of unimplemented syscall events. const ( unimplementedSyscallsMaxRate = 100 // events per second unimplementedSyscallBurst = 1000 // events @@ -1292,9 +1296,9 @@ const ( // EmitUnimplementedEvent emits an UnimplementedSyscall event via the event // channel. func (k *Kernel) EmitUnimplementedEvent(ctx context.Context) { - if k.unimplementedSyscallEmitter == nil { + k.unimplementedSyscallEmitterOnce.Do(func() { k.unimplementedSyscallEmitter = eventchannel.RateLimitedEmitterFrom(eventchannel.DefaultEmitter, unimplementedSyscallsMaxRate, unimplementedSyscallBurst) - } + }) t := TaskFromContext(ctx) k.unimplementedSyscallEmitter.Emit(&uspb.UnimplementedSyscall{ |