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Commit 95c59ea5 authored by Vlad Popa's avatar Vlad Popa
Browse files

Fix deadlock caused by wrong locking order 

The correct order to lock is mSettingsLock -> VolumeStreamState.class.
In some cases this order was broken which lead to some deadlocks. Add
quick fix. Might still need to investigate whether we need both locks,
for details see b/287066735

Test: atest AudioManagerTest
Bug: 283969676
Bug: 283436164
Change-Id: I27afb8da18511291f8786833bf55250097a8e705
Merged-In: Id9c9fe4bd78d23dff92bf3a32c6f16d8e7b96720
parent 0665ff26

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

+127 −95
Original line number Diff line number Diff line
@@ -3666,6 +3666,8 @@ public class AudioService extends IAudioService.Stub 
     * and aliases before mute change changed and after.

     */

    private void muteAliasStreams(int streamAlias, boolean state) {

        // Locking mSettingsLock to avoid inversion when calling doMute -> updateVolumeGroupIndex

        synchronized (mSettingsLock) {

            synchronized (VolumeStreamState.class) {

                List<Integer> streamsToMute = new ArrayList<>();

                for (int stream = 0; stream < mStreamStates.length; stream++) {
@@ -3674,7 +3676,8 @@ public class AudioService extends IAudioService.Stub 
                        if (!(mCameraSoundForced

                                && (vss.getStreamType()

                                == AudioSystem.STREAM_SYSTEM_ENFORCED))) {

                        boolean changed = vss.mute(state, /* apply= */ false, "muteAliasStreams");

                            boolean changed = vss.mute(state, /* apply= */ false,

                                    "muteAliasStreams");

                            if (changed) {

                                streamsToMute.add(stream);

                            }
@@ -3687,6 +3690,7 @@ public class AudioService extends IAudioService.Stub 
                });

            }

        }

    }















    private void broadcastMuteSetting(int streamType, boolean isMuted) {















        // Stream mute changed, fire the intent.









@@ -3699,6 +3703,9 @@ public class AudioService extends IAudioService.Stub













    // Called after a delay when volume down is pressed while muted















    private void onUnmuteStream(int stream, int flags) {















        boolean wasMuted;













        // Locking mSettingsLock to avoid inversion when calling vss.mute -> vss.doMute ->













        // vss.updateVolumeGroupIndex













        synchronized (mSettingsLock) {















            synchronized (VolumeStreamState.class) {















                final VolumeStreamState streamState = mStreamStates[stream];















                // if unmuting causes a change, it was muted









@@ -3714,6 +3721,7 @@ public class AudioService extends IAudioService.Stub













                }















            }















        }













    }





























    @GuardedBy("mHdmiClientLock")















    private void maybeSendSystemAudioStatusCommand(boolean isMuteAdjust) {










@@ -7611,9 +7619,13 @@ public class AudioService extends IAudioService.Stub













                Log.i(TAG, String.format("onAccessoryPlugMediaUnmute unmuting device=%d [%s]",















                        newDevice, AudioSystem.getOutputDeviceName(newDevice)));















            }













            // Locking mSettingsLock to avoid inversion when calling vss.mute -> vss.doMute ->













            // vss.updateVolumeGroupIndex













            synchronized (mSettingsLock) {















                mStreamStates[AudioSystem.STREAM_MUSIC].mute(false, "onAccessoryPlugMediaUnmute");















            }















        }













    }





























    /**















     * See AudioManager.hasHapticChannels(Context, Uri).










@@ -7646,11 +7658,16 @@ public class AudioService extends IAudioService.Stub













                continue;















            }















        }

























        // need mSettingsLock for vgs.applyAllVolumes -> vss.setIndex which grabs this lock after













        // VSS.class. Locking order needs to be preserved













        synchronized (mSettingsLock) {















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















                final VolumeGroupState vgs = sVolumeGroupStates.valueAt(i);















                vgs.applyAllVolumes(/* userSwitch= */ false);















            }















        }













    }





























    private void ensureValidAttributes(AudioVolumeGroup avg) {















        boolean hasAtLeastOneValidAudioAttributes = avg.getAudioAttributes().stream()










@@ -7685,11 +7702,16 @@ public class AudioService extends IAudioService.Stub













        if (DEBUG_VOL) {















            Log.v(TAG, "restoreVolumeGroups");















        }

























        // need mSettingsLock for vgs.applyAllVolumes -> vss.setIndex which grabs this lock after













        // VSS.class. Locking order needs to be preserved













        synchronized (mSettingsLock) {















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















                final VolumeGroupState vgs = sVolumeGroupStates.valueAt(i);















                vgs.applyAllVolumes(false/*userSwitch*/);















            }















        }













    }





























    private void dumpVolumeGroups(PrintWriter pw) {















        pw.println("\nVolume Groups (device: index)");










@@ -7824,6 +7846,7 @@ public class AudioService extends IAudioService.Stub













        }





























        public void adjustVolume(int direction, int flags) {













            synchronized (mSettingsLock) {















                synchronized (AudioService.VolumeStreamState.class) {















                    int device = getDeviceForVolume();















                    int previousIndex = getIndex(device);










@@ -7870,6 +7893,7 @@ public class AudioService extends IAudioService.Stub













                    }















                }















            }













        }





























        public int getVolumeIndex() {















            synchronized (AudioService.VolumeStreamState.class) {









@@ -7878,6 +7902,7 @@ public class AudioService extends IAudioService.Stub













        }





























        public void setVolumeIndex(int index, int flags) {













            synchronized (mSettingsLock) {















                synchronized (AudioService.VolumeStreamState.class) {















                    if (mUseFixedVolume) {















                        return;









@@ -7885,6 +7910,7 @@ public class AudioService extends IAudioService.Stub













                    setVolumeIndex(index, getDeviceForVolume(), flags);















                }















            }













        }





























        @GuardedBy("AudioService.VolumeStreamState.class")















        private void setVolumeIndex(int index, int device, int flags) {










@@ -8689,6 +8715,10 @@ public class AudioService extends IAudioService.Stub



























        // If associated to volume group, update group cache















        private void updateVolumeGroupIndex(int device, boolean forceMuteState) {













            // need mSettingsLock when called from setIndex for vgs.mute -> vgs.applyAllVolumes ->













            // vss.setIndex which grabs this lock after VSS.class. Locking order needs to be













            // preserved













            synchronized (mSettingsLock) {















                synchronized (VolumeStreamState.class) {















                    if (mVolumeGroupState != null) {















                        int groupIndex = (getIndex(device) + 5) / 10;









@@ -8696,13 +8726,14 @@ public class AudioService extends IAudioService.Stub













                            Log.d(TAG, "updateVolumeGroupIndex for stream " + mStreamType















                                    + ", muted=" + mIsMuted + ", device=" + device + ", index="















                                    + getIndex(device) + ", group " + mVolumeGroupState.name()













                                + " Muted=" + mVolumeGroupState.isMuted() + ", Index=" + groupIndex













                                + ", forceMuteState=" + forceMuteState);













                                    + " Muted=" + mVolumeGroupState.isMuted() + ", Index="













                                    + groupIndex + ", forceMuteState=" + forceMuteState);















                        }















                        mVolumeGroupState.updateVolumeIndex(groupIndex, device);















                        // Only propage mute of stream when applicable















                        if (isMutable()) {













                        // For call stream, align mute only when muted, not when index is set to 0













                            // For call stream, align mute only when muted, not when index is set to













                            // 0















                            mVolumeGroupState.mute(















                                    forceMuteState ? mIsMuted :















                                            (groupIndex == 0 && !isCallStream(mStreamType))









@@ -8711,6 +8742,7 @@ public class AudioService extends IAudioService.Stub













                    }















                }















            }













        }





























        /**















         * Mute/unmute the stream