Commit ee57a1a4 authored by Andrew Osmond's avatar Andrew Osmond
Browse files

Bug 1374278 - Fix a race condition between GPUChild and CompositorManagerChild... 

Bug 1374278 - Fix a race condition between GPUChild and CompositorManagerChild when the GPU process crashes. r=dvander
parent a1222374

gfx/ipc/GPUProcessManager.cpp

+5 −1
Original line number Diff line number Diff line
@@ -203,7 +203,11 @@ GPUProcessManager::EnsureGPUReady() 
void

GPUProcessManager::EnsureCompositorManagerChild()

{

  if (CompositorManagerChild::IsInitialized()) {

  base::ProcessId gpuPid = EnsureGPUReady()

                           ? mGPUChild->OtherPid()

                           : base::GetCurrentProcId();



  if (CompositorManagerChild::IsInitialized(gpuPid)) {

    return;

  }

gfx/layers/ipc/CompositorManagerChild.cpp

+12 −6
Original line number Diff line number Diff line
@@ -19,19 +19,21 @@ namespace layers { 
StaticRefPtr<CompositorManagerChild> CompositorManagerChild::sInstance;



/* static */ bool

CompositorManagerChild::IsInitialized()

CompositorManagerChild::IsInitialized(base::ProcessId aGPUPid)

{

  MOZ_ASSERT(NS_IsMainThread());

  return sInstance && sInstance->CanSend();

  // Since GPUChild and CompositorManagerChild will race on ActorDestroy, we

  // cannot know if the CompositorManagerChild is about to be released but has

  // yet to be. As such, we need to verify the GPU PID matches as well.

  return sInstance && sInstance->CanSend() && sInstance->OtherPid() == aGPUPid;

}



/* static */ bool

CompositorManagerChild::InitSameProcess(uint32_t aNamespace)

{

  MOZ_ASSERT(NS_IsMainThread());

  if (NS_WARN_IF(sInstance &&

                 sInstance->OtherPid() == base::GetCurrentProcId())) {

    MOZ_ASSERT_UNREACHABLE("Already initialized");

  if (NS_WARN_IF(IsInitialized(base::GetCurrentProcId()))) {

    MOZ_ASSERT_UNREACHABLE("Already initialized same process");

    return false;

  }
@@ -47,8 +49,12 @@ CompositorManagerChild::Init(Endpoint<PCompositorManagerChild>&& aEndpoint, 
{

  MOZ_ASSERT(NS_IsMainThread());

  if (sInstance) {

    // Since GPUChild and CompositorManagerChild will race on ActorDestroy, we

    // cannot know if the CompositorManagerChild has yet to be released or not.

    // To avoid an unnecessary reinitialization, we verify the GPU PID actually

    // changed.

    MOZ_ASSERT(sInstance->mNamespace != aNamespace);

    MOZ_RELEASE_ASSERT(!sInstance->CanSend());

    MOZ_RELEASE_ASSERT(sInstance->OtherPid() != aEndpoint.OtherPid());

  }



  sInstance = new CompositorManagerChild(Move(aEndpoint), aNamespace);

gfx/layers/ipc/CompositorManagerChild.h

+1 −1
Original line number Diff line number Diff line
@@ -24,7 +24,7 @@ class CompositorManagerChild : public PCompositorManagerChild 
  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CompositorManagerChild)



public:

  static bool IsInitialized();

  static bool IsInitialized(base::ProcessId aPid);

  static bool InitSameProcess(uint32_t aNamespace);

  static bool Init(Endpoint<PCompositorManagerChild>&& aEndpoint,

                   uint32_t aNamespace);