From 8a9e7a1f9490dc0c103c82fac74087459ddf4c16 Mon Sep 17 00:00:00 2001
From: Obi Okafor <obi.okafor@sonyericsson.com>
Date: Thu, 11 Mar 2010 01:00:02 +0100
Subject: Fix for deadlock between StatusBarService and
 NotificationManagerService

A ServerThread holding a lock on mQueue in StatusBarService invoked a
callback in NotificationManagerService which required a lock on
mNotificationList. At  the same time, a BinderThread holding a lock on
mNotificationList was attempting to post a message to StatusBarService
which requires lock on mQueue. The fix is to release the lock on mQueue
in handleMessage() before running the actions at the end of the method.
---
 .../android/server/status/StatusBarService.java    | 33 +++++++++++++---------
 1 file changed, 19 insertions(+), 14 deletions(-)

diff --git a/services/java/com/android/server/status/StatusBarService.java b/services/java/com/android/server/status/StatusBarService.java
index 34921d66cdc8..9ccd38b6fc95 100644
--- a/services/java/com/android/server/status/StatusBarService.java
+++ b/services/java/com/android/server/status/StatusBarService.java
@@ -552,15 +552,17 @@ public class StatusBarService extends IStatusBar.Stub
                 doRevealAnimation();
                 return;
             }
+            boolean expand = false;
+            boolean doExpand = false;
+            boolean doDisable = false;
+            int disableWhat = 0;
+
             synchronized (mQueue) {
                 boolean wasExpanded = mExpanded;
 
                 // for each one in the queue, find all of the ones with the same key
                 // and collapse that down into a final op and/or call to setVisibility, etc
-                boolean expand = wasExpanded;
-                boolean doExpand = false;
-                boolean doDisable = false;
-                int disableWhat = 0;
+                expand = wasExpanded;
                 int N = mQueue.size();
                 while (N > 0) {
                     PendingOp op = mQueue.get(0);
@@ -634,18 +636,21 @@ public class StatusBarService extends IStatusBar.Stub
                 if (mQueue.size() != 0) {
                     throw new RuntimeException("Assertion failed: mQueue.size=" + mQueue.size());
                 }
-                if (doExpand) {
-                    // this is last so that we capture all of the pending changes before doing it
-                    if (expand) {
-                        animateExpand();
-                    } else {
-                        animateCollapse();
-                    }
-                }
-                if (doDisable) {
-                    performDisableActions(disableWhat);
+            }
+            // This must be done outside the synchronized block above to prevent a deadlock where
+            // we call into the NotificationManagerService and it is in turn attempting to post a
+            // message to our queue.
+            if (doExpand) {
+                // this is last so that we capture all of the pending changes before doing it
+                if (expand) {
+                    animateExpand();
+                } else {
+                    animateCollapse();
                 }
             }
+            if (doDisable) {
+                performDisableActions(disableWhat);
+            }
         }
     }
 
-- 
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