From 55119e823e068743ada99e63a53ae08a927cd92c Mon Sep 17 00:00:00 2001 From: Lucas Lin Date: Thu, 7 May 2020 10:12:30 +0000 Subject: [PATCH] Broadcast ACTION_NETWORK_STATS_UPDATED in NetworkStatsHandler There is a corner case which may cause the deadlock: When NetworkStatsService tried to broadcast the intent, NetworkStatsService was waiting for a lock which was hold by ActivityManagerService. In the same time, ActivityManagerService was waiting for ActiveService#startServiceInnerLocked() to get a lock which was hold by ConnectivityService. ConnectivityService was waiting for a lock which was hold by BatteryStatsImpl. BatteryStatsImpl was waiting for a lock which was hold by NetworkStatsService, and the lock was locked by NetworkStatsService when NetworkStatsService tried to broadcast the intent. To prevent deadlock when broadcasting the intent in performPollLocked(), move the intent broadcasting from performPollLocked() to NetworkStatsHandler. Bug: 150418178 Bug: 155155473 Test: 1. Create the second user and see if the device will do factory reset or not. 2. Factory reset manually and see if there is a deadlock. Change-Id: I80569cb4388beb3fd6cbf64a7885bccee8b1c53c Merged-In: Icf88d3e7a38562ab15187f6c71bc8fb0486d37c0 (cherry picked from commit 3f8ab0350450202910ea702799570c538e96d5cd) --- .../android/server/net/NetworkStatsService.java | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/services/core/java/com/android/server/net/NetworkStatsService.java b/services/core/java/com/android/server/net/NetworkStatsService.java index 1951fc071d..adf017633c 100644 --- a/services/core/java/com/android/server/net/NetworkStatsService.java +++ b/services/core/java/com/android/server/net/NetworkStatsService.java @@ -178,6 +178,9 @@ public class NetworkStatsService extends INetworkStatsService.Stub { // Perform polling, persist network, and register the global alert again. private static final int MSG_PERFORM_POLL_REGISTER_ALERT = 2; private static final int MSG_UPDATE_IFACES = 3; + // A message for broadcasting ACTION_NETWORK_STATS_UPDATED in handler thread to prevent + // deadlock. + private static final int MSG_BROADCAST_NETWORK_STATS_UPDATED = 4; /** Flags to control detail level of poll event. */ private static final int FLAG_PERSIST_NETWORK = 0x1; @@ -386,6 +389,13 @@ public class NetworkStatsService extends INetworkStatsService.Stub { registerGlobalAlert(); break; } + case MSG_BROADCAST_NETWORK_STATS_UPDATED: { + final Intent updatedIntent = new Intent(ACTION_NETWORK_STATS_UPDATED); + updatedIntent.setFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY); + mContext.sendBroadcastAsUser(updatedIntent, UserHandle.ALL, + READ_NETWORK_USAGE_HISTORY); + break; + } } } } @@ -1513,10 +1523,7 @@ public class NetworkStatsService extends INetworkStatsService.Stub { } // finally, dispatch updated event to any listeners - final Intent updatedIntent = new Intent(ACTION_NETWORK_STATS_UPDATED); - updatedIntent.setFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY); - mContext.sendBroadcastAsUser(updatedIntent, UserHandle.ALL, - READ_NETWORK_USAGE_HISTORY); + mHandler.sendMessage(mHandler.obtainMessage(MSG_BROADCAST_NETWORK_STATS_UPDATED)); Trace.traceEnd(TRACE_TAG_NETWORK); }