diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index 467d00ee34..203a3259c6 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -189,6 +189,9 @@ Release 2.0.3-alpha - Unreleased
     MAPREDUCE-4736. Remove obsolete option [-rootDir] from TestDFSIO.
     (Brandon Li via suresh)
 
+    MAPREDUCE-4637. Handle TaskAttempt diagnostic updates while in the NEW and 
+    UNASSIGNED states. (Mayank Bansal via sseth)
+
 Release 2.0.2-alpha - 2012-09-07 
 
   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 687edc379c..a39a1bc6b9 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
@@ -200,6 +200,10 @@ public abstract class TaskAttemptImpl implements
          TaskAttemptEventType.TA_KILL, new KilledTransition())
      .addTransition(TaskAttemptStateInternal.NEW, TaskAttemptStateInternal.FAILED,
          TaskAttemptEventType.TA_FAILMSG, new FailedTransition())
+     .addTransition(TaskAttemptStateInternal.NEW,
+          TaskAttemptStateInternal.NEW,
+          TaskAttemptEventType.TA_DIAGNOSTICS_UPDATE,
+          DIAGNOSTIC_INFORMATION_UPDATE_TRANSITION)
 
      // Transitions from the UNASSIGNED state.
      .addTransition(TaskAttemptStateInternal.UNASSIGNED,
@@ -211,6 +215,10 @@ public abstract class TaskAttemptImpl implements
      .addTransition(TaskAttemptStateInternal.UNASSIGNED, TaskAttemptStateInternal.FAILED,
          TaskAttemptEventType.TA_FAILMSG, new DeallocateContainerTransition(
              TaskAttemptStateInternal.FAILED, true))
+     .addTransition(TaskAttemptStateInternal.UNASSIGNED,
+          TaskAttemptStateInternal.UNASSIGNED,
+          TaskAttemptEventType.TA_DIAGNOSTICS_UPDATE,
+          DIAGNOSTIC_INFORMATION_UPDATE_TRANSITION)
 
      // Transitions from the ASSIGNED state.
      .addTransition(TaskAttemptStateInternal.ASSIGNED, TaskAttemptStateInternal.RUNNING,
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 88e32b337c..0a381facaf 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
@@ -546,6 +546,105 @@ public class TestTaskAttempt{
         eventHandler.internalError);
   }
 
+  @Test
+  public void testAppDiognosticEventOnUnassignedTask() throws Exception {
+    ApplicationId appId = BuilderUtils.newApplicationId(1, 2);
+    ApplicationAttemptId appAttemptId = BuilderUtils.newApplicationAttemptId(
+        appId, 0);
+    JobId jobId = MRBuilderUtils.newJobId(appId, 1);
+    TaskId taskId = MRBuilderUtils.newTaskId(jobId, 1, TaskType.MAP);
+    TaskAttemptId attemptId = MRBuilderUtils.newTaskAttemptId(taskId, 0);
+    Path jobFile = mock(Path.class);
+
+    MockEventHandler eventHandler = new MockEventHandler();
+    TaskAttemptListener taListener = mock(TaskAttemptListener.class);
+    when(taListener.getAddress()).thenReturn(
+        new InetSocketAddress("localhost", 0));
+
+    JobConf jobConf = new JobConf();
+    jobConf.setClass("fs.file.impl", StubbedFS.class, FileSystem.class);
+    jobConf.setBoolean("fs.file.impl.disable.cache", true);
+    jobConf.set(JobConf.MAPRED_MAP_TASK_ENV, "");
+    jobConf.set(MRJobConfig.APPLICATION_ATTEMPT_ID, "10");
+
+    TaskSplitMetaInfo splits = mock(TaskSplitMetaInfo.class);
+    when(splits.getLocations()).thenReturn(new String[] { "127.0.0.1" });
+
+    AppContext appCtx = mock(AppContext.class);
+    ClusterInfo clusterInfo = mock(ClusterInfo.class);
+    Resource resource = mock(Resource.class);
+    when(appCtx.getClusterInfo()).thenReturn(clusterInfo);
+    when(clusterInfo.getMinContainerCapability()).thenReturn(resource);
+    when(resource.getMemory()).thenReturn(1024);
+
+    TaskAttemptImpl taImpl = new MapTaskAttemptImpl(taskId, 1, eventHandler,
+        jobFile, 1, splits, jobConf, taListener, mock(OutputCommitter.class),
+        mock(Token.class), new Credentials(), new SystemClock(), appCtx);
+
+    NodeId nid = BuilderUtils.newNodeId("127.0.0.1", 0);
+    ContainerId contId = BuilderUtils.newContainerId(appAttemptId, 3);
+    Container container = mock(Container.class);
+    when(container.getId()).thenReturn(contId);
+    when(container.getNodeId()).thenReturn(nid);
+    when(container.getNodeHttpAddress()).thenReturn("localhost:0");
+    taImpl.handle(new TaskAttemptEvent(attemptId,
+        TaskAttemptEventType.TA_SCHEDULE));
+    taImpl.handle(new TaskAttemptDiagnosticsUpdateEvent(attemptId,
+        "Task got killed"));
+    assertFalse(
+        "InternalError occurred trying to handle TA_DIAGNOSTICS_UPDATE on assigned task",
+        eventHandler.internalError);
+  }
+
+  @Test
+  public void testAppDiognosticEventOnNewTask() throws Exception {
+    ApplicationId appId = BuilderUtils.newApplicationId(1, 2);
+    ApplicationAttemptId appAttemptId = BuilderUtils.newApplicationAttemptId(
+        appId, 0);
+    JobId jobId = MRBuilderUtils.newJobId(appId, 1);
+    TaskId taskId = MRBuilderUtils.newTaskId(jobId, 1, TaskType.MAP);
+    TaskAttemptId attemptId = MRBuilderUtils.newTaskAttemptId(taskId, 0);
+    Path jobFile = mock(Path.class);
+
+    MockEventHandler eventHandler = new MockEventHandler();
+    TaskAttemptListener taListener = mock(TaskAttemptListener.class);
+    when(taListener.getAddress()).thenReturn(
+        new InetSocketAddress("localhost", 0));
+
+    JobConf jobConf = new JobConf();
+    jobConf.setClass("fs.file.impl", StubbedFS.class, FileSystem.class);
+    jobConf.setBoolean("fs.file.impl.disable.cache", true);
+    jobConf.set(JobConf.MAPRED_MAP_TASK_ENV, "");
+    jobConf.set(MRJobConfig.APPLICATION_ATTEMPT_ID, "10");
+
+    TaskSplitMetaInfo splits = mock(TaskSplitMetaInfo.class);
+    when(splits.getLocations()).thenReturn(new String[] { "127.0.0.1" });
+
+    AppContext appCtx = mock(AppContext.class);
+    ClusterInfo clusterInfo = mock(ClusterInfo.class);
+    Resource resource = mock(Resource.class);
+    when(appCtx.getClusterInfo()).thenReturn(clusterInfo);
+    when(clusterInfo.getMinContainerCapability()).thenReturn(resource);
+    when(resource.getMemory()).thenReturn(1024);
+
+    TaskAttemptImpl taImpl = new MapTaskAttemptImpl(taskId, 1, eventHandler,
+        jobFile, 1, splits, jobConf, taListener, mock(OutputCommitter.class),
+        mock(Token.class), new Credentials(), new SystemClock(), appCtx);
+
+    NodeId nid = BuilderUtils.newNodeId("127.0.0.1", 0);
+    ContainerId contId = BuilderUtils.newContainerId(appAttemptId, 3);
+    Container container = mock(Container.class);
+    when(container.getId()).thenReturn(contId);
+    when(container.getNodeId()).thenReturn(nid);
+    when(container.getNodeHttpAddress()).thenReturn("localhost:0");
+    taImpl.handle(new TaskAttemptDiagnosticsUpdateEvent(attemptId,
+        "Task got killed"));
+    assertFalse(
+        "InternalError occurred trying to handle TA_DIAGNOSTICS_UPDATE on assigned task",
+        eventHandler.internalError);
+  }
+    
+  
   public static class MockEventHandler implements EventHandler {
     public boolean internalError;