From 0e851c78e3badf8b64b47ce53710b096e84334fb Mon Sep 17 00:00:00 2001
From: Anders 3 Fridlund <anders3.fridlund@sonymobile.com>
Date: Thu, 7 Jun 2012 11:24:10 +0200
Subject: [PATCH] Move NTP updates outside locks

When the ServerThread handles ACTION_SHUTDOWN intent it sometimes get
stuck on mStatsLock in NetworkStatsService.java.
0  com.android.server.net.NetworkStatsService$5.onReceive()
1  android.app.LoadedApk$ReceiverDispatcher$Args.run()
2  android.os.Handler.handleCallback()
3  android.os.Handler.dispatchMessage()
4  android.os.Looper.loop()
5  com.android.server.ServerThread.run()
This happens when the NetworkStats thread is already holding the
mStatsLock while updating NTP.
0  libcore.io.Posix.getaddrinfo()
1  libcore.io.ForwardingOs.getaddrinfo()
2  java.net.InetAddress.lookupHostByName()
3  java.net.InetAddress.getAllByNameImpl()
4  java.net.InetAddress.getByName()
5  android.net.SntpClient.requestTime()
6  android.util.NtpTrustedTime.forceRefresh()
7  com.android.server.net.NetworkStatsService.performPoll()
8  com.android.server.net.NetworkStatsService.access$100()
9  com.android.server.net.NetworkStatsService$2.onReceive()
10 android.app.LoadedApk$ReceiverDispatcher$Args.run()
11 android.os.Handler.handleCallback()
12 android.os.Handler.dispatchMessage()
13 android.os.Looper.loop()
14 android.os.HandlerThread.run()
Since the NTP update consists of several socket operations it may get
stuck long enough to trigger a System Server Watchdog even though the
socket timeout is set to 20 second.
Further, the NTP update doesn't actually need to be performed inside
the locks and an attempt to change this was made earlier, but the code
wasn't actually moved outside the locks.

Change-Id: Ib37a2b8c2d51a01adb7ff01764f82309433703f0
---
 .../com/android/server/net/NetworkStatsService.java    | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/services/java/com/android/server/net/NetworkStatsService.java b/services/java/com/android/server/net/NetworkStatsService.java
index 0efdead7f9..a3b44e26d8 100644
--- a/services/java/com/android/server/net/NetworkStatsService.java
+++ b/services/java/com/android/server/net/NetworkStatsService.java
@@ -939,14 +939,14 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
     }
 
     private void performPoll(int flags) {
+        // try refreshing time source when stale
+        if (mTime.getCacheAge() > mSettings.getTimeCacheMaxAge()) {
+            mTime.forceRefresh();
+        }
+
         synchronized (mStatsLock) {
             mWakeLock.acquire();
 
-            // try refreshing time source when stale
-            if (mTime.getCacheAge() > mSettings.getTimeCacheMaxAge()) {
-                mTime.forceRefresh();
-            }
-
             try {
                 performPollLocked(flags);
             } finally {