HADOOP-3489. Fix NPE in SafeModeMonitor. Contributed by Lohit Vijayarenu.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/core/trunk@664201 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -524,6 +524,8 @@ Trunk (unreleased changes)
 
     HADOOP-3463. Hadoop-daemons script should cd to $HADOOP_HOME. (omalley)
 
+    HADOOP-3489. Fix NPE in SafeModeMonitor. (Lohit Vijayarenu via shv)
+
 Release 0.17.0 - 2008-05-18
 
   INCOMPATIBLE CHANGES

src/java/org/apache/hadoop/dfs/FSNamesystem.java

@@ -3948,7 +3948,7 @@ class FSNamesystem implements FSConstants, FSNamesystemMBean {
     /**
      */
     public void run() {
-      while (fsRunning && !safeMode.canLeave()) {
+      while (fsRunning && (safeMode != null && !safeMode.canLeave())) {
         try {
           Thread.sleep(recheckInterval);
         } catch (InterruptedException ie) {