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Commit 3094d955 authored by Jean-Michel Trivi's avatar Jean-Michel Trivi
Browse files

Fix deadlock in AudioService 

Locks related to audio focus and remote control should always be
 taken in the following order:
 1/ audio focus lock
 2/ remote control stack
 3/ current remote control client generation

Change-Id: If8be11bfef92849957e692b2bd52adbd67a2ef0b
parent 4b6df6a3

media/java/android/media/AudioService.java

+41 −39
Original line number Diff line number Diff line
@@ -3072,7 +3072,7 @@ public class AudioService extends IAudioService.Stub { 
    /**

     * Update the remote control displays with the new "focused" client generation

     */

    private void setNewRcClientOnDisplays_syncRcStack(int newClientGeneration,

    private void setNewRcClientOnDisplays_syncAfRcsCurrc(int newClientGeneration,

            ComponentName newClientEventReceiver, boolean clearing) {

        // NOTE: Only one IRemoteControlDisplay supported in this implementation

        if (mRcDisplay != null) {
@@ -3091,7 +3091,7 @@ public class AudioService extends IAudioService.Stub { 
    /**

     * Update the remote control clients with the new "focused" client generation

     */

    private void setNewRcClientGenerationOnClients_syncRcStack(int newClientGeneration) {

    private void setNewRcClientGenerationOnClients_syncAfRcsCurrc(int newClientGeneration) {

        Iterator<RemoteControlStackEntry> stackIterator = mRCStack.iterator();

        while(stackIterator.hasNext()) {

            RemoteControlStackEntry se = stackIterator.next();
@@ -3115,15 +3115,13 @@ public class AudioService extends IAudioService.Stub { 
     * @param clearing true if the new client generation value maps to a remote control update

     *    where the display should be cleared.

     */

    private void setNewRcClient(int newClientGeneration, ComponentName newClientEventReceiver,

            boolean clearing) {

        synchronized(mRCStack) {

    private void setNewRcClient_syncAfRcsCurrc(int newClientGeneration,

            ComponentName newClientEventReceiver, boolean clearing) {

        // send the new valid client generation ID to all displays

            setNewRcClientOnDisplays_syncRcStack(newClientGeneration, newClientEventReceiver,

        setNewRcClientOnDisplays_syncAfRcsCurrc(newClientGeneration, newClientEventReceiver,

                clearing);

        // send the new valid client generation ID to all clients

            setNewRcClientGenerationOnClients_syncRcStack(newClientGeneration);

        }

        setNewRcClientGenerationOnClients_syncAfRcsCurrc(newClientGeneration);

    }



    /**
@@ -3133,11 +3131,13 @@ public class AudioService extends IAudioService.Stub { 
        // TODO remove log before release

        Log.i(TAG, "Clear remote control display");



        synchronized(mRCStack) {

            synchronized(mCurrentRcLock) {

                mCurrentRcClientGen++;



                // synchronously update the displays and clients with the new client generation

            setNewRcClient(mCurrentRcClientGen, null /*event receiver*/, true /*clearing*/);

                setNewRcClient_syncAfRcsCurrc(mCurrentRcClientGen,

                        null /*event receiver*/, true /*clearing*/);

            }

        }

    }
@@ -3145,15 +3145,16 @@ public class AudioService extends IAudioService.Stub { 
     * Called when processing MSG_RCDISPLAY_UPDATE event

     */

    private void onRcDisplayUpdate(RemoteControlStackEntry rcse, int flags /* USED ?*/) {

        synchronized(mRCStack) {

            synchronized(mCurrentRcLock) {

                if ((mCurrentRcClient != null) && (mCurrentRcClient.equals(rcse.mRcClient))) {

                    // TODO remove log before release

                    Log.i(TAG, "Display/update remote control ");



                    mCurrentRcClientGen++;



                // synchronously update the displays and clients with the new client generation

                setNewRcClient(mCurrentRcClientGen,

                    // synchronously update the displays and clients with

                    //      the new client generation

                    setNewRcClient_syncAfRcsCurrc(mCurrentRcClientGen,

                            rcse.mReceiverComponent /*event receiver*/,

                            false /*clearing*/);
@@ -3172,6 +3173,7 @@ public class AudioService extends IAudioService.Stub { 
                }

            }

        }

    }





    /**