From 53d1e66080d004477da3a87f901b2e2d3db24775 Mon Sep 17 00:00:00 2001
From: tiger_huang <tiger_huang@htc.com>
Date: Tue, 23 Feb 2016 20:34:52 +0800
Subject: [PATCH] Make accessing mWaitingForDrawn thread-safe

mWaitingForDrawn can be accessed by multiple threads, but it was not
protected by the mWindowMap lock perfectly.

Change-Id: I128ba1a00f40af83b051c0d1df4350d0635a9dff
---
 .../android/server/wm/WindowManagerService.java    | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/services/core/java/com/android/server/wm/WindowManagerService.java b/services/core/java/com/android/server/wm/WindowManagerService.java
index 6d3d5d6daa600..68d6de4e1b01a 100644
--- a/services/core/java/com/android/server/wm/WindowManagerService.java
+++ b/services/core/java/com/android/server/wm/WindowManagerService.java
@@ -11982,6 +11982,7 @@ public class WindowManagerService extends IWindowManager.Stub
 
         @Override
         public void waitForAllWindowsDrawn(Runnable callback, long timeout) {
+            boolean allWindowsDrawn = false;
             synchronized (mWindowMap) {
                 mWaitingForDrawnCallback = callback;
                 final WindowList windows = getDefaultWindowListLocked();
@@ -12002,13 +12003,16 @@ public class WindowManagerService extends IWindowManager.Stub
                     }
                 }
                 requestTraversalLocked();
+                mH.removeMessages(H.WAITING_FOR_DRAWN_TIMEOUT);
+                if (mWaitingForDrawn.isEmpty()) {
+                    allWindowsDrawn = true;
+                } else {
+                    mH.sendEmptyMessageDelayed(H.WAITING_FOR_DRAWN_TIMEOUT, timeout);
+                    checkDrawnWindowsLocked();
+                }
             }
-            mH.removeMessages(H.WAITING_FOR_DRAWN_TIMEOUT);
-            if (mWaitingForDrawn.isEmpty()) {
+            if (allWindowsDrawn) {
                 callback.run();
-            } else {
-                mH.sendEmptyMessageDelayed(H.WAITING_FOR_DRAWN_TIMEOUT, timeout);
-                checkDrawnWindowsLocked();
             }
         }