From 82c700f53b6afdc14e6ffdd7f7bf201fb1af8f46 Mon Sep 17 00:00:00 2001
From: tiger_huang <tiger_huang@htc.com>
Date: Thu, 1 Oct 2015 14:11:27 +0800
Subject: [PATCH] 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
---
 .../com/android/server/wm/WindowManagerService.java   | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/services/core/java/com/android/server/wm/WindowManagerService.java b/services/core/java/com/android/server/wm/WindowManagerService.java
index 97a38925a8ab2..31777e8945d32 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 @@ public class WindowManagerService extends IWindowManager.Stub
         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;