commit 7bb2581e6f404da0edba9ebb81b0d0593715eb40
author Magnus Edlund <magnus.edlund.x@sonyericsson.com> Wed Feb 24 15:45:06 2010 +0100
committer Jean-Baptiste Queru <jbq@google.com> Mon Mar 01 09:12:07 2010 -0800
tree 1ca3c4dc2d86df5df6a55db38fdd5804eef81cdd
parent 853226b147fb7be7709ce55e7100ebfea6719435

Fix problem with restarting an application process that recently has died.

There exists a race condition when starting a process that recently has died.
If the ActivityManager receives the death notification for the died process
after the new process has been started but before an application thread has
been attached to the new process will the newly created process be removed
during the cleanup of the died process. If this happens when sending a broadcast
could it result in an ANR.

This is solved by doing the clean up before starting a new process that uses
the same process record.

services/java/com/android/server/am/ActivityManagerService.java

diff --git a/services/java/com/android/server/am/ActivityManagerService.java b/services/java/com/android/server/am/ActivityManagerService.java
index 1a22a26a..5f6356d 100644
--- a/services/java/com/android/server/am/ActivityManagerService.java
+++ b/services/java/com/android/server/am/ActivityManagerService.java
@@ -1905,11 +1905,16 @@
                 + " app=" + app + " knownToBeDead=" + knownToBeDead
                 + " thread=" + (app != null ? app.thread : null)
                 + " pid=" + (app != null ? app.pid : -1));
-        if (app != null &&
-                (!knownToBeDead || app.thread == null) && app.pid > 0) {
-            return app;
+        if (app != null && app.pid > 0) {
+            if (!knownToBeDead || app.thread == null) {
+                return app;
+            } else {
+                // An application record is attached to a previous process,
+                // clean it up now.
+                handleAppDiedLocked(app, true);
+            }
         }
-        
+
         String hostingNameStr = hostingName != null
                 ? hostingName.flattenToShortString() : null;
         
@@ -4553,7 +4558,9 @@
 
         mProcDeaths[0]++;
         
-        if (app.thread != null && app.thread.asBinder() == thread.asBinder()) {
+        // Clean up already done if the process has been re-started.
+        if (app.pid == pid && app.thread != null &&
+                app.thread.asBinder() == thread.asBinder()) {
             Log.i(TAG, "Process " + app.processName + " (pid " + pid
                     + ") has died.");
             EventLog.writeEvent(LOG_AM_PROCESS_DIED, app.pid, app.processName);
@@ -4603,6 +4610,11 @@
                     scheduleAppGcsLocked();
                 }
             }
+        } else if (app.pid != pid) {
+            // A new process has already been started.
+            Log.i(TAG, "Process " + app.processName + " (pid " + pid
+                    + ") has died and restarted (pid " + app.pid + ").");
+            EventLog.writeEvent(LOG_AM_PROCESS_DIED, pid, app.processName);
         } else if (Config.LOGD) {
             Log.d(TAG, "Received spurious death notification for thread "
                     + thread.asBinder());
@@ -5424,6 +5436,8 @@
                 finishReceiverLocked(br.receiver, br.resultCode, br.resultData,
                         br.resultExtras, br.resultAbort, true);
                 scheduleBroadcastsLocked();
+                // We need to reset the state if we fails to start the receiver.
+                br.state = BroadcastRecord.IDLE;
             }
         }