diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index 67adcbd1f9..da5ee0bd41 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -626,6 +626,10 @@ Release 2.7.2 - UNRELEASED
     MAPREDUCE-5982. Task attempts that fail from the ASSIGNED state can
     disappear (Chang Li via jlowe)
 
+    MAPREDUCE-6492. AsyncDispatcher exit with NPE on
+    TaskAttemptImpl#sendJHStartEventForAssignedFailTask (Bibin A Chundatt via
+    jlowe)
+
 Release 2.7.1 - 2015-07-06 
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/v2/app/job/impl/TaskAttemptImpl.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/v2/app/job/impl/TaskAttemptImpl.java
index a7becdbfac..db4f585a8d 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/v2/app/job/impl/TaskAttemptImpl.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/v2/app/job/impl/TaskAttemptImpl.java
@@ -1486,7 +1486,9 @@ private static JobCounterUpdateEvent createJobCounterUpdateEventTAKilled(
 
   private static void
       sendJHStartEventForAssignedFailTask(TaskAttemptImpl taskAttempt) {
-    TaskAttemptContainerLaunchedEvent event;
+    if (null == taskAttempt.container) {
+      return;
+    }
     taskAttempt.launchTime = taskAttempt.clock.getTime();
 
     InetSocketAddress nodeHttpInetAddr =
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/test/java/org/apache/hadoop/mapreduce/v2/app/job/impl/TestTaskAttempt.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/test/java/org/apache/hadoop/mapreduce/v2/app/job/impl/TestTaskAttempt.java
index 6b4656aaf4..1ed8098988 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/test/java/org/apache/hadoop/mapreduce/v2/app/job/impl/TestTaskAttempt.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/test/java/org/apache/hadoop/mapreduce/v2/app/job/impl/TestTaskAttempt.java
@@ -774,6 +774,14 @@ public void testAppDiognosticEventOnUnassignedTask() throws Exception {
     assertFalse(
         "InternalError occurred trying to handle TA_DIAGNOSTICS_UPDATE on assigned task",
         eventHandler.internalError);
+    try {
+      taImpl.handle(new TaskAttemptEvent(attemptId,
+          TaskAttemptEventType.TA_KILL));
+      Assert.assertTrue("No exception on UNASSIGNED STATE KILL event", true);
+    } catch (Exception e) {
+      Assert.assertFalse(
+          "Exception not expected for UNASSIGNED STATE KILL event", true);
+    }
   }
 
   @Test