Commit 99e2b6c1 authored Dec 23, 2022 by Daniel Committed by Daniel Kim Dec 28, 2022

Fix deadlock by not acquiring lock when reporting proximity

There is a deadlock situation from AttentionManagerService acquiring
lock before callings back to its clients with the proximity update. This
can cause a deadlock because the clients, while holding their own locks,
can call AttentionManagerService again.

Thread 1:
  Acquires attention lock -> AttentionManager Service reports proximityUpdate to VoiceInteraction -> tries to acquire voice lock

Thread 2:
  Acquires voice lock -> VoiceService tries to cancel proximity updates
  -> tries to acquire attention lock

The deadlock can be fixed by removing the acquiring attention lock step
before reporting proximityUpdates to the clients.

Bug: 261143716
Test: atest CtsAttentionServiceDeviceTestCases
Change-Id: I9f7d520cbcfd57032a9476853acad025fd7a6b95
Merged-In: I9f7d520cbcfd57032a9476853acad025fd7a6b95
(cherry picked from commit a28af297)

parent fa71876c

services/core/java/com/android/server/attention/AttentionManagerService.java

+1 −1

Original line number	Diff line number	Diff line
		@@ -668,8 +668,8 @@ public class AttentionManagerService extends SystemService {
		mIProximityUpdateCallback = new IProximityUpdateCallback.Stub() {
		@Override
		public void onProximityUpdate(double distance) {
		synchronized (mLock) {
		mCallbackInternal.onProximityUpdate(distance);
		synchronized (mLock) {
		freeIfInactiveLocked();
		}
		}