Commit 2b0ee672 authored Mar 08, 2018 by Pawin Vongmasa

Stop GraphicBufferSource's looper without locking

Before this CL, the following sequence of events could cause a deadlock:
- Binder thread: Acquires the mutex (mMutex) inside release().
- Looper thread: Blocks inside onMessageReceived() as it tries to
acquire the mutex.
- Binder thread: Calls mLooper->stop() inside release(), which waits for
the looper thread to finish executing onMessageReceived().

Test: make cts -j123 && cts-tradefed run cts-dev -m \
CtsMediaTestCases --compatibility:module-arg \
CtsMediaTestCases:include-annotation:\
android.platform.test.annotations.RequiresDevice

Bug: 74170420
Change-Id: Ie63b19107f10937f7a301fe74b38f15076cc0ed9

parent ecff3f95

media/libstagefright/bqhelper/GraphicBufferSource.cpp

+22 −17

Original line number	Diff line number	Diff line
		@@ -421,12 +421,14 @@ Status GraphicBufferSource::stop() {
		}

		Status GraphicBufferSource::release(){
		sp<ALooper> looper;
		{
		Mutex::Autolock autoLock(mMutex);
		looper = mLooper;
		if (mLooper != NULL) {
		mLooper->unregisterHandler(mReflector->id());
		mReflector.clear();

		mLooper->stop();
		mLooper.clear();
		}

		@@ -440,7 +442,10 @@ Status GraphicBufferSource::release(){
		mLatestBuffer.mBuffer.reset();
		mComponent.clear();
		mExecuting = false;

		}
		if (looper != NULL) {
		looper->stop();
		}
		return Status::ok();
		}