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Commit e36f1e4b authored by Corey Tabaka's avatar Corey Tabaka
Browse files

Fix concurrent access bug in VrFlinger. 

VR surface queues have erroneous concurrent access from two threads
because of misplaced lock guards. Move the locking to cover the
queue accesses.

Bug: 62886596
Bug: 63149525
Test: Extensive logging shows that buffers are accessed in the
 correct order and that the consistency of the queues is now
 maintained.

Change-Id: I649e3d75a2230cf3aff50886df9958917d3aa4bf
parent a36bf926

libs/vr/libvrflinger/display_surface.cpp

+4 −2
Original line number Diff line number Diff line
@@ -248,11 +248,12 @@ void ApplicationDisplaySurface::OnQueueEvent( 
           "ApplicationDisplaySurface::OnQueueEvent: queue_id=%d events=%x",

           consumer_queue->id(), events);



  std::lock_guard<std::mutex> autolock(lock_);



  // Always give the queue a chance to handle its internal bookkeeping.

  consumer_queue->HandleQueueEvents();



  // Check for hangup and remove a queue that is no longer needed.

  std::lock_guard<std::mutex> autolock(lock_);

  if (consumer_queue->hung_up()) {

    ALOGD_IF(TRACE, "ApplicationDisplaySurface::OnQueueEvent: Removing queue.");

    UnregisterQueue(consumer_queue);
@@ -317,11 +318,12 @@ void DirectDisplaySurface::OnQueueEvent( 
  ALOGD_IF(TRACE, "DirectDisplaySurface::OnQueueEvent: queue_id=%d events=%x",

           consumer_queue->id(), events);



  std::lock_guard<std::mutex> autolock(lock_);



  // Always give the queue a chance to handle its internal bookkeeping.

  consumer_queue->HandleQueueEvents();



  // Check for hangup and remove a queue that is no longer needed.

  std::lock_guard<std::mutex> autolock(lock_);

  if (consumer_queue->hung_up()) {

    ALOGD_IF(TRACE, "DirectDisplaySurface::OnQueueEvent: Removing queue.");

    UnregisterQueue(consumer_queue);