From 5ed21bd9aca01f01e2b27e2bfa031d31c775eec7 Mon Sep 17 00:00:00 2001
From: riddle_hsu <riddle_hsu@htc.com>
Date: Sat, 15 Nov 2014 18:07:26 +0800
Subject: [PATCH] [ActivityManager] Avoid orphan ContentProviderRecord.

<Symptom>
Binder threads wait forever results ANR/system hang.

<Root cause>
When X is accessing Y's provider.
Before Y publishing its provider to notify X,
someone invokes killBackgroundProcesses to kill Y.
In removeProcessLocked, it will pass restarting=true
and allowRestart=true to handleAppDiedLocked.

When the clean flow going to removeDyingProviderLocked.
The variable will be inLaunching=true always=false.
Then it will not notify the ContentProviderRecord.
And also due to the ContentProviderConnection waiting=true,
it will do nothing and just return true to
cleanUpApplicationRecordLocked to set restart as true.

But due to restarting=true, the restart flow will not execute,
then the waiting ContentProviderRecord for X will be orphan
and keep waiting.

<Reproduce step>
Service X query provider Y when X's oom adj is SERVICE_ADJ,
before Y's publish provider, invoke killBackgroundProcesses
to Y's package.
Then use command "adb shell dumpsys activity prov"
Y will always in "Launching content providers".

<Solution>
For not restarting case, pass restarting=false to
handleAppDiedLocked to let the provider process can be restarted.

A more simple way maybe just change to keep below 2 lines:
  app.kill(reason, true);
  handleAppDiedLocked(app, callerWillRestart, allowRestart);

Change-Id: I8992cb851fce4dbe6255da71d60390e1a33cb9c7
---
 .../android/server/am/ActivityManagerService.java   | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)
 mode change 100755 => 100644 services/core/java/com/android/server/am/ActivityManagerService.java

diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
old mode 100755
new mode 100644
index 8dfb3217c0af1..25237a91bf3c9
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -5958,17 +5958,20 @@ public final class ActivityManagerService extends ActivityManagerNative
             if (app.isolated) {
                 mBatteryStatsService.removeIsolatedUid(app.uid, app.info.uid);
             }
-            app.kill(reason, true);
-            handleAppDiedLocked(app, true, allowRestart);
-            removeLruProcessLocked(app);
-
+            boolean willRestart = false;
             if (app.persistent && !app.isolated) {
                 if (!callerWillRestart) {
-                    addAppLocked(app.info, false, null /* ABI override */);
+                    willRestart = true;
                 } else {
                     needRestart = true;
                 }
             }
+            app.kill(reason, true);
+            handleAppDiedLocked(app, willRestart, allowRestart);
+            if (willRestart) {
+                removeLruProcessLocked(app);
+                addAppLocked(app.info, false, null /* ABI override */);
+            }
         } else {
             mRemovedProcesses.add(app);
         }