Watchdog can get deadlocked on activity manager
Bug: 3351719
Change-Id: Ie5bb39e5ff92f41c14ae59240173fab9c2491a91
diff --git a/services/java/com/android/server/Watchdog.java b/services/java/com/android/server/Watchdog.java
index 1b885f5..2a25c2a 100644
--- a/services/java/com/android/server/Watchdog.java
+++ b/services/java/com/android/server/Watchdog.java
@@ -425,7 +425,7 @@
// First collect stack traces from all threads of the system process.
// Then kill this process so that the system will restart.
- String name = (mCurrentMonitor != null) ?
+ final String name = (mCurrentMonitor != null) ?
mCurrentMonitor.getClass().getName() : "null";
EventLog.writeEvent(EventLogTags.WATCHDOG, name);
@@ -434,7 +434,8 @@
if (mPhonePid > 0) pids.add(mPhonePid);
// Pass !waitedHalf so that just in case we somehow wind up here without having
// dumped the halfway stacks, we properly re-initialize the trace file.
- File stack = ActivityManagerService.dumpStackTraces(!waitedHalf, pids, null, null);
+ final File stack = ActivityManagerService.dumpStackTraces(
+ !waitedHalf, pids, null, null);
// Give some extra time to make sure the stack traces get written.
// The system's been hanging for a minute, another second or two won't hurt much.
@@ -445,7 +446,19 @@
dumpKernelStackTraces();
}
- mActivity.addErrorToDropBox("watchdog", null, null, null, name, null, stack, null);
+ // Try to add the error to the dropbox, but assuming that the ActivityManager
+ // itself may be deadlocked. (which has happened, causing this statement to
+ // deadlock and the watchdog as a whole to be ineffective)
+ Thread dropboxThread = new Thread("watchdogWriteToDropbox") {
+ public void run() {
+ mActivity.addErrorToDropBox(
+ "watchdog", null, null, null, name, null, stack, null);
+ }
+ };
+ dropboxThread.start();
+ try {
+ dropboxThread.join(2000); // wait up to 2 seconds for it to return.
+ } catch (InterruptedException ignored) {}
// Only kill the process if the debugger is not attached.
if (!Debug.isDebuggerConnected()) {