commit 82c700f53b6afdc14e6ffdd7f7bf201fb1af8f46
author tiger_huang <tiger_huang@htc.com> Thu Oct 01 14:11:27 2015 +0800
committer tiger_huang <tiger_huang@htc.com> Thu Oct 01 14:11:27 2015 +0800
tree f59b97cf2ccc04521a0a36a1b3f8b71d590d3e2a
parent 899110f3012eb9ab2056d8ee182d5bdab0ecae19

Make accessing mInputMethodTarget thread-safe

Use the lock to prevent other threads clearing mInputMethodTarget
while we are accessing members of mInputMethodTarget, or it will
cause system server crash due to unexpected NullPointerException.

Change-Id: Iec3bed916a019827364ddaf63a89270a4c407a47

services/core/java/com/android/server/wm/WindowManagerService.java

diff --git a/services/core/java/com/android/server/wm/WindowManagerService.java b/services/core/java/com/android/server/wm/WindowManagerService.java
index 97a38925..31777e8 100644
--- a/services/core/java/com/android/server/wm/WindowManagerService.java
+++ b/services/core/java/com/android/server/wm/WindowManagerService.java
@@ -6185,10 +6185,13 @@
         int retryCount = 0;
         WindowState appWin = null;
 
-        final boolean appIsImTarget = mInputMethodTarget != null
-                && mInputMethodTarget.mAppToken != null
-                && mInputMethodTarget.mAppToken.appToken != null
-                && mInputMethodTarget.mAppToken.appToken.asBinder() == appToken;
+        boolean appIsImTarget;
+        synchronized(mWindowMap) {
+            appIsImTarget = mInputMethodTarget != null
+                    && mInputMethodTarget.mAppToken != null
+                    && mInputMethodTarget.mAppToken.appToken != null
+                    && mInputMethodTarget.mAppToken.appToken.asBinder() == appToken;
+        }
 
         final int aboveAppLayer = (mPolicy.windowTypeToLayerLw(TYPE_APPLICATION) + 1)
                 * TYPE_LAYER_MULTIPLIER + TYPE_LAYER_OFFSET;