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Commit 085346ac authored by Jean-Michel Trivi's avatar Jean-Michel Trivi
Browse files

AudioService: fix deadlock 

Source of deadlock:
Thread A:
 readAudioSettings()
  -> checkAllAliasStreamVolumes()
    -> synchronized (VolumeStreamState.class)
         -> mStreamStates[streamType].setAllIndexes()
            -> synchronized (mSettingsLock)
Thread B:
 updateStreamVolumeAlias()
  -> mStreamStates[ACCESSIBILITY].setAllIndexes()
     -> synchronized (mSettingsLock)
        -> synchronized (VolumeStreamState.class)

Fix:
 Ensure all calls to VSS.setAllIndexes() are synchronized
 on mSettingsLock then on VolumeStreamState.class.

Bug: 72122435
Test: see bug for repro
Change-Id: I16ad1d1df88256291c36d8f5b8ebe830fe1b0b84
parent 11817c6b

services/core/java/com/android/server/audio/AudioService.java

+53 −49
Original line number Diff line number Diff line
@@ -1042,6 +1042,7 @@ public class AudioService extends IAudioService.Stub 
    }



    private void checkAllAliasStreamVolumes() {

        synchronized (mSettingsLock) {

            synchronized (VolumeStreamState.class) {

                int numStreamTypes = AudioSystem.getNumStreamTypes();

                for (int streamType = 0; streamType < numStreamTypes; streamType++) {
@@ -1054,6 +1055,7 @@ public class AudioService extends IAudioService.Stub 
                }

            }

        }

    }



    private void checkAllFixedVolumeDevices()

    {
@@ -1155,13 +1157,16 @@ public class AudioService extends IAudioService.Stub 
        if (updateVolumes && mStreamStates != null) {

            updateDefaultVolumes();



            mStreamStates[AudioSystem.STREAM_DTMF].setAllIndexes(mStreamStates[dtmfStreamAlias],

                    caller);



            synchronized (mSettingsLock) {

                synchronized (VolumeStreamState.class) {

                    mStreamStates[AudioSystem.STREAM_DTMF]

                            .setAllIndexes(mStreamStates[dtmfStreamAlias], caller);

                    mStreamStates[AudioSystem.STREAM_ACCESSIBILITY].mVolumeIndexSettingName =

                            System.VOLUME_SETTINGS_INT[a11yStreamAlias];

                    mStreamStates[AudioSystem.STREAM_ACCESSIBILITY].setAllIndexes(

                            mStreamStates[a11yStreamAlias], caller);

                }

            }

            if (sIndependentA11yVolume) {

                // restore the a11y values from the settings

                mStreamStates[AudioSystem.STREAM_ACCESSIBILITY].readSettings();
@@ -4604,12 +4609,12 @@ public class AudioService extends IAudioService.Stub 
         * @param srcStream

         * @param caller

         */

        // must be sync'd on mSettingsLock before VolumeStreamState.class

        @GuardedBy("VolumeStreamState.class")

        public void setAllIndexes(VolumeStreamState srcStream, String caller) {

            if (mStreamType == srcStream.mStreamType) {

                return;

            }

            synchronized (mSettingsLock) {

                synchronized (VolumeStreamState.class) {

            int srcStreamType = srcStream.getStreamType();

            // apply default device volume from source stream to all devices first in case

            // some devices are present in this stream state but not in source stream state
@@ -4628,17 +4633,14 @@ public class AudioService extends IAudioService.Stub 
                setIndex(index, device, caller);

            }

        }

            }

        }



        @GuardedBy("mSettingsLock")

        // must be sync'd on mSettingsLock before VolumeStreamState.class

        @GuardedBy("VolumeStreamState.class")

        public void setAllIndexesToMax() {

            synchronized (VolumeStreamState.class) {

            for (int i = 0; i < mIndexMap.size(); i++) {

                mIndexMap.put(mIndexMap.keyAt(i), mIndexMax);

            }

        }

        }



        public void mute(boolean state) {

            boolean changed = false;
@@ -6224,6 +6226,7 @@ public class AudioService extends IAudioService.Stub 
                mCameraSoundForced = cameraSoundForced;

                if (cameraSoundForcedChanged) {

                    if (!mIsSingleVolume) {

                        synchronized (VolumeStreamState.class) {

                            VolumeStreamState s = mStreamStates[AudioSystem.STREAM_SYSTEM_ENFORCED];

                            if (cameraSoundForced) {

                                s.setAllIndexesToMax();
@@ -6234,6 +6237,7 @@ public class AudioService extends IAudioService.Stub 
                                mRingerModeAffectedStreams |=

                                        (1 << AudioSystem.STREAM_SYSTEM_ENFORCED);

                            }

                        }

                        // take new state into account for streams muted by ringer mode

                        setRingerModeInt(getRingerModeInternal(), false);

                    }