diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index d5993698def..9686d887692 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -52,6 +52,10 @@ Trunk (unreleased changes)
 
   BUG FIXES
 
+    MAPREDUCE-3953. [Gridmix] Gridmix throws NPE and does not simulate a
+                    job if the trace contains null taskStatus for a task.
+                    (ravigummadi)
+
     MAPREDUCE-3829. [Gridmix] Gridmix should give better error message when
                     input data directory already exists and -generate opton is
                     given.(ravigummadi)
diff --git a/hadoop-mapreduce-project/src/contrib/gridmix/src/java/org/apache/hadoop/mapred/gridmix/JobFactory.java b/hadoop-mapreduce-project/src/contrib/gridmix/src/java/org/apache/hadoop/mapred/gridmix/JobFactory.java
index f5404e842ff..427174295c8 100644
--- a/hadoop-mapreduce-project/src/contrib/gridmix/src/java/org/apache/hadoop/mapred/gridmix/JobFactory.java
+++ b/hadoop-mapreduce-project/src/contrib/gridmix/src/java/org/apache/hadoop/mapred/gridmix/JobFactory.java
@@ -215,7 +215,13 @@ abstract class JobFactory<T> implements Gridmix.Component<Void>,StatListener<T>
     return null == job ? null : new FilterJobStory(job) {
       @Override
       public TaskInfo getTaskInfo(TaskType taskType, int taskNumber) {
-        return new MinTaskInfo(this.job.getTaskInfo(taskType, taskNumber));
+        TaskInfo info = this.job.getTaskInfo(taskType, taskNumber);
+        if (info != null) {
+          info = new MinTaskInfo(info);
+        } else {
+          info = new MinTaskInfo(new TaskInfo(0, 0, 0, 0, 0));
+        }
+        return info;
       }
     };
   }
diff --git a/hadoop-tools/hadoop-rumen/src/main/java/org/apache/hadoop/tools/rumen/ZombieJob.java b/hadoop-tools/hadoop-rumen/src/main/java/org/apache/hadoop/tools/rumen/ZombieJob.java
index fa9378cad46..3857e1fea90 100644
--- a/hadoop-tools/hadoop-rumen/src/main/java/org/apache/hadoop/tools/rumen/ZombieJob.java
+++ b/hadoop-tools/hadoop-rumen/src/main/java/org/apache/hadoop/tools/rumen/ZombieJob.java
@@ -638,6 +638,9 @@ public class ZombieJob implements JobStory {
   }
 
   private TaskInfo getTaskInfo(LoggedTask loggedTask) {
+    if (loggedTask == null) {
+      return new TaskInfo(0, 0, 0, 0, 0);
+    }
     List<LoggedTaskAttempt> attempts = loggedTask.getAttempts();
 
     long inputBytes = -1;