YARN-2874. Dead lock in DelegationTokenRenewer which blocks RM to execute any further apps. (Naganarasimha G R via kasha)

hadoop-yarn-project/CHANGES.txt

@@ -175,6 +175,9 @@ Release 2.7.0 - UNRELEASED
     YARN-2894. Fixed a bug regarding application view acl when RM fails over.
     (Rohith Sharmaks via jianhe)
 
+    YARN-2874. Dead lock in "DelegationTokenRenewer" which blocks RM to execute
+    any further apps. (Naganarasimha G R via kasha)
+
 Release 2.6.0 - 2014-11-18
 
   INCOMPATIBLE CHANGES

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/security/DelegationTokenRenewer.java

@@ -20,7 +20,6 @@ package org.apache.hadoop.yarn.server.resourcemanager.security;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
-import java.security.PrivilegedAction;
 import java.security.PrivilegedExceptionAction;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -39,6 +38,7 @@ import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.locks.ReadWriteLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 
@@ -445,15 +445,15 @@ public class DelegationTokenRenewer extends AbstractService {
    */
   private class RenewalTimerTask extends TimerTask {
     private DelegationTokenToRenew dttr;
-    private boolean cancelled = false;
+    private AtomicBoolean cancelled = new AtomicBoolean(false);
     
     RenewalTimerTask(DelegationTokenToRenew t) {  
       dttr = t;  
     }
     
     @Override
-    public synchronized void run() {
-      if (cancelled) {
+    public void run() {
+      if (cancelled.get()) {
         return;
       }
 
@@ -475,8 +475,8 @@ public class DelegationTokenRenewer extends AbstractService {
     }
 
     @Override
-    public synchronized boolean cancel() {
-      cancelled = true;
+    public boolean cancel() {
+      cancelled.set(true);
       return super.cancel();
     }
   }