commit e6771c41e8ae905a616f3fd369d0eacfcd2003b9
author Jeff Brown <jeffbrown@google.com> Tue Jul 16 15:18:19 2013 -0700
committer The Android Automerger <android-build@google.com> Wed Jul 17 14:59:19 2013 -0700
tree 7cc0e3b91a4e3695ca51374cb6d2a53a97966e8e
parent 5892fc5d8aaf546e605196c3dc48d8f9e193dc2a

Fix missing lock in power manager.

The display wake lock and other internal state could become
out of sync if we happened to execute the power manager's update
function concurrently due to the missing lock.

This bug can be trigged due to display state changes or proximity
sensor updated.  Although it would be extremely rare, we have
some evidence of this happening on at least a few devices resulting
in rapid power drain with the screen off or a crash.

Bug: 9880044
Change-Id: I3c674ce429621a50cbb36c3a01883d5f388205b2
(cherry picked from commit d91e417b06388694db213257b4df6b4dd78e0d49)

services/java/com/android/server/power/PowerManagerService.java

diff --git a/services/java/com/android/server/power/PowerManagerService.java b/services/java/com/android/server/power/PowerManagerService.java
index 1203e02..6f70712 100644
--- a/services/java/com/android/server/power/PowerManagerService.java
+++ b/services/java/com/android/server/power/PowerManagerService.java
@@ -1702,24 +1702,30 @@
             new DisplayPowerController.Callbacks() {
         @Override
         public void onStateChanged() {
-            mDirty |= DIRTY_ACTUAL_DISPLAY_POWER_STATE_UPDATED;
-            updatePowerStateLocked();
+            synchronized (mLock) {
+                mDirty |= DIRTY_ACTUAL_DISPLAY_POWER_STATE_UPDATED;
+                updatePowerStateLocked();
+            }
         }
 
         @Override
         public void onProximityPositive() {
-            mProximityPositive = true;
-            mDirty |= DIRTY_PROXIMITY_POSITIVE;
-            updatePowerStateLocked();
+            synchronized (mLock) {
+                mProximityPositive = true;
+                mDirty |= DIRTY_PROXIMITY_POSITIVE;
+                updatePowerStateLocked();
+            }
         }
 
         @Override
         public void onProximityNegative() {
-            mProximityPositive = false;
-            mDirty |= DIRTY_PROXIMITY_POSITIVE;
-            userActivityNoUpdateLocked(SystemClock.uptimeMillis(),
-                    PowerManager.USER_ACTIVITY_EVENT_OTHER, 0, Process.SYSTEM_UID);
-            updatePowerStateLocked();
+            synchronized (mLock) {
+                mProximityPositive = false;
+                mDirty |= DIRTY_PROXIMITY_POSITIVE;
+                userActivityNoUpdateLocked(SystemClock.uptimeMillis(),
+                        PowerManager.USER_ACTIVITY_EVENT_OTHER, 0, Process.SYSTEM_UID);
+                updatePowerStateLocked();
+            }
         }
     };