From 84e9a10fde8a4ae3da4f88d7911c154933aa457f Mon Sep 17 00:00:00 2001 From: Eric Laurent Date: Thu, 23 Sep 2010 16:10:16 -0700 Subject: Fix issue 3007862 Removed a cross deadlock condition between audioflinger and audio policy service mutexes. Audioflinger::createEffect() locks audioflinger mutex and then calls AudioSystem::getOutputForEffect() which ends up in AudioPolicyService::getOutputForEffect() which locks audio policy service mutex. If at the same time, the command thread in audio policy service is processing a command(set volume, set route...), the mutex is locked and the command will call one audioflinger method which in turn will attempt to lock audioflinger mutex. The fix consists in releasing audioflinger mutex before calling getOutputForEffect(). Change-Id: Id44e7feb36e0a295731f6aa97cf32d022edd34d0 --- services/audioflinger/AudioFlinger.cpp | 89 +++++++++++++++++++--------------- 1 file changed, 49 insertions(+), 40 deletions(-) (limited to 'services') diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp index 56de765..8a732ed 100644 --- a/services/audioflinger/AudioFlinger.cpp +++ b/services/audioflinger/AudioFlinger.cpp @@ -4653,29 +4653,44 @@ sp AudioFlinger::createEffect(pid_t pid, goto Exit; } - { - Mutex::Autolock _l(mLock); + // check audio settings permission for global effects + if (sessionId == AudioSystem::SESSION_OUTPUT_MIX && !settingsAllowed()) { + lStatus = PERMISSION_DENIED; + goto Exit; + } - // check audio settings permission for global effects - if (sessionId == AudioSystem::SESSION_OUTPUT_MIX && !settingsAllowed()) { - lStatus = PERMISSION_DENIED; - goto Exit; - } + // Session AudioSystem::SESSION_OUTPUT_STAGE is reserved for output stage effects + // that can only be created by audio policy manager (running in same process) + if (sessionId == AudioSystem::SESSION_OUTPUT_STAGE && getpid() != pid) { + lStatus = PERMISSION_DENIED; + goto Exit; + } - // Session AudioSystem::SESSION_OUTPUT_STAGE is reserved for output stage effects - // that can only be created by audio policy manager (running in same process) - if (sessionId == AudioSystem::SESSION_OUTPUT_STAGE && getpid() != pid) { - lStatus = PERMISSION_DENIED; - goto Exit; - } + // check recording permission for visualizer + if ((memcmp(&pDesc->type, SL_IID_VISUALIZATION, sizeof(effect_uuid_t)) == 0 || + memcmp(&pDesc->uuid, &VISUALIZATION_UUID_, sizeof(effect_uuid_t)) == 0) && + !recordingAllowed()) { + lStatus = PERMISSION_DENIED; + goto Exit; + } - // check recording permission for visualizer - if ((memcmp(&pDesc->type, SL_IID_VISUALIZATION, sizeof(effect_uuid_t)) == 0 || - memcmp(&pDesc->uuid, &VISUALIZATION_UUID_, sizeof(effect_uuid_t)) == 0) && - !recordingAllowed()) { - lStatus = PERMISSION_DENIED; + if (output == 0) { + if (sessionId == AudioSystem::SESSION_OUTPUT_STAGE) { + // output must be specified by AudioPolicyManager when using session + // AudioSystem::SESSION_OUTPUT_STAGE + lStatus = BAD_VALUE; goto Exit; + } else if (sessionId == AudioSystem::SESSION_OUTPUT_MIX) { + // if the output returned by getOutputForEffect() is removed before we lock the + // mutex below, the call to checkPlaybackThread_l(output) below will detect it + // and we will exit safely + output = AudioSystem::getOutputForEffect(&desc); } + } + + { + Mutex::Autolock _l(mLock); + if (!EffectIsNullUuid(&pDesc->uuid)) { // if uuid is specified, request effect descriptor @@ -4744,32 +4759,24 @@ sp AudioFlinger::createEffect(pid_t pid, // If output is not specified try to find a matching audio session ID in one of the // output threads. - // TODO: allow attachment of effect to inputs + // If output is 0 here, sessionId is neither SESSION_OUTPUT_STAGE nor SESSION_OUTPUT_MIX + // because of code checking output when entering the function. if (output == 0) { - if (sessionId == AudioSystem::SESSION_OUTPUT_STAGE) { - // output must be specified by AudioPolicyManager when using session - // AudioSystem::SESSION_OUTPUT_STAGE - lStatus = BAD_VALUE; - goto Exit; - } else if (sessionId == AudioSystem::SESSION_OUTPUT_MIX) { - output = AudioSystem::getOutputForEffect(&desc); - LOGV("createEffect() got output %d for effect %s", output, desc.name); - } else { - // 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) { - output = mPlaybackThreads.keyAt(i); - break; - } - } - // 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 - if (output == 0 && mPlaybackThreads.size()) { - output = mPlaybackThreads.keyAt(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) { + output = mPlaybackThreads.keyAt(i); + break; } } + // 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 + if (output == 0 && mPlaybackThreads.size()) { + output = mPlaybackThreads.keyAt(0); + } } + LOGV("createEffect() got output %d for effect %s", output, desc.name); PlaybackThread *thread = checkPlaybackThread_l(output); if (thread == NULL) { LOGE("createEffect() unknown output thread"); @@ -4777,6 +4784,8 @@ sp AudioFlinger::createEffect(pid_t pid, goto Exit; } + // TODO: allow attachment of effect to inputs + wclient = mClients.valueFor(pid); if (wclient != NULL) { -- cgit v1.1