am 4e141a4f: am 1802399c: Merge "fix deadlock in audioflinger::createEffect()" into klp-dev (62dbe93f) · Commits · e / os / android_frameworks_av

services/audioflinger/AudioFlinger.cpp

+18 −21

Original line number	Diff line number	Diff line
		@@ -2104,9 +2104,6 @@ sp<IEffect> AudioFlinger::createEffect(
		}

		{
		Mutex::Autolock _l(mLock);


		if (!EffectIsNullUuid(&pDesc->uuid)) {
		// if uuid is specified, request effect descriptor
		lStatus = EffectGetDescriptor(&pDesc->uuid, &desc);
		@@ -2179,6 +2176,15 @@ sp<IEffect> AudioFlinger::createEffect(

		// return effect descriptor
		*pDesc = desc;
		if (io == 0 && sessionId == AUDIO_SESSION_OUTPUT_MIX) {
		// if the output returned by getOutputForEffect() is removed before we lock the
		// mutex below, the call to checkPlaybackThread_l(io) below will detect it
		// and we will exit safely
		io = AudioSystem::getOutputForEffect(&desc);
		ALOGV("createEffect got output %d", io);
		}

		Mutex::Autolock _l(mLock);

		// If output is not specified try to find a matching audio session ID in one of the
		// output threads.
		@@ -2192,14 +2198,6 @@ sp<IEffect> AudioFlinger::createEffect(
		lStatus = BAD_VALUE;
		goto Exit;
		}
		if (sessionId == AUDIO_SESSION_OUTPUT_MIX) {
		// if the output returned by getOutputForEffect() is removed before we lock the
		// mutex below, the call to checkPlaybackThread_l(io) below will detect it
		// and we will exit safely
		io = AudioSystem::getOutputForEffect(&desc);
		ALOGV("createEffect got output %d", io);
		}
		if (io == 0) {
		// look for the thread where the specified audio session is present
		for (size_t i = 0; i < mPlaybackThreads.size(); i++) {
		if (mPlaybackThreads.valueAt(i)->hasAudioSession(sessionId) != 0) {
		@@ -2215,7 +2213,6 @@ sp<IEffect> AudioFlinger::createEffect(
		}
		}
		}
		}
		// If no output thread contains the requested session ID, default to
		// first output. The effect chain will be moved to the correct output
		// thread when a track with the same session ID is created

services/audioflinger/Effects.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -25,6 +25,10 @@
		// state changes or resource modifications. Always respect the following order
		// if multiple mutexes must be acquired to avoid cross deadlock:
		// AudioFlinger -> ThreadBase -> EffectChain -> EffectModule
		// In addition, methods that lock the AudioPolicyService mutex (getOutputForEffect(),
		// startOutput()...) should never be called with AudioFlinger or Threadbase mutex locked
		// to avoid cross deadlock with other clients calling AudioPolicyService methods that in turn
		// call AudioFlinger thus locking the same mutexes in the reverse order.

		// The EffectModule class is a wrapper object controlling the effect engine implementation
		// in the effect library. It prevents concurrent calls to process() and command() functions