From 19e84047ab8ec6b61d5e2bfd79909fe8942943af Mon Sep 17 00:00:00 2001 From: Shibin George Date: Tue, 14 Jun 2016 20:42:13 +0530 Subject: [PATCH] Fix deadlock b/w ActivityManagerService and MediaSessionService While handling adjustVolume and finishReceiver at the same time, system_server gets into deadlock situation where ActivityManagerService lock and MediaSessionService lock are getting acquired in reverse order. To fix this, adjustSuggestedStreamVolume() is shifted to MediaSessionService's Handler thread. https://code.google.com/p/android/issues/detail?id=213014 Change-Id: I3125c890546c8ab7c4df530bb68ba87cd688f8ce --- .../server/media/MediaSessionService.java | 25 +++++++++++++------ 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/services/core/java/com/android/server/media/MediaSessionService.java b/services/core/java/com/android/server/media/MediaSessionService.java index 7028fa6695f66..1a320d2bdb80a 100644 --- a/services/core/java/com/android/server/media/MediaSessionService.java +++ b/services/core/java/com/android/server/media/MediaSessionService.java @@ -887,13 +887,24 @@ public class MediaSessionService extends SystemService implements Monitor { } return; } - try { - String packageName = getContext().getOpPackageName(); - mAudioService.adjustSuggestedStreamVolume(direction, suggestedStream, - flags, packageName, TAG); - } catch (RemoteException e) { - Log.e(TAG, "Error adjusting default volume.", e); - } + + // Execute mAudioService.adjustSuggestedStreamVolume() on + // handler thread of MediaSessionService. + // This will release the MediaSessionService.mLock sooner and avoid + // a potential deadlock between MediaSessionService.mLock and + // ActivityManagerService lock. + mHandler.post(new Runnable() { + @Override + public void run() { + try { + String packageName = getContext().getOpPackageName(); + mAudioService.adjustSuggestedStreamVolume(direction, suggestedStream, + flags, packageName, TAG); + } catch (RemoteException e) { + Log.e(TAG, "Error adjusting default volume.", e); + } + } + }); } else { session.adjustVolume(direction, flags, getContext().getPackageName(), UserHandle.myUserId(), true);