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Commit 14dc3cb6 authored by Eric Laurent's avatar Eric Laurent
Browse files

IAudioFlinger: create Audio Policy Service before calling AudioFlinger 

Make sure we connect to Audio Policy Service before calling into AudioFlinger
implementation to avoid the following deadlock
 1) AudioFlinger locks its global mutex and calls into Audio Policy Service
 2) If this is the first time Audio Policy Service is queried from inside
    audioserver process this will trigger Audio Policy Manager initialization.
 3) Audio Policy Manager initialization calls into AudioFlinger which will
    try to lock its global mutex
    => Deadlock

Bug: 167155843
Test: manual audioserver crash test
Change-Id: Ic30fc4dd460f4a3ce64bc43c5aa58cddff3bd707
parent 7c9db322

media/libaudioclient/IAudioFlinger.cpp

+11 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 


#include <binder/IPCThreadState.h>

#include <binder/Parcel.h>

#include <media/IAudioPolicyService.h>

#include <mediautils/ServiceUtilities.h>

#include <mediautils/TimeCheck.h>

#include "IAudioFlinger.h"
@@ -1024,6 +1025,16 @@ status_t BnAudioFlinger::onTransact( 
    std::string tag("IAudioFlinger command " + std::to_string(code));

    TimeCheck check(tag.c_str());



    // Make sure we connect to Audio Policy Service before calling into AudioFlinger:

    //  - AudioFlinger can call into Audio Policy Service with its global mutex held

    //  - If this is the first time Audio Policy Service is queried from inside audioserver process

    //  this will trigger Audio Policy Manager initialization.

    //  - Audio Policy Manager initialization calls into AudioFlinger which will try to lock

    //  its global mutex and a deadlock will occur.

    if (IPCThreadState::self()->getCallingPid() != getpid()) {

        AudioSystem::get_audio_policy_service();

    }



    switch (code) {

        case CREATE_TRACK: {

            CHECK_INTERFACE(IAudioFlinger, data, reply);