diff --git a/CHANGES.txt b/CHANGES.txt
index 063e1c511e2..04a7ba5aa4a 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -34,6 +34,9 @@ Trunk (unreleased changes)
     HADOOP-7045. TestDU fails on systems with local file systems with 
     extended attributes. (eli)
 
+    HADOOP-6939. Inconsistent lock ordering in
+    AbstractDelegationTokenSecretManager. (Todd Lipcon via tomwhite)
+
 Release 0.22.0 - Unreleased
 
   INCOMPATIBLE CHANGES
diff --git a/src/java/org/apache/hadoop/security/token/delegation/AbstractDelegationTokenSecretManager.java b/src/java/org/apache/hadoop/security/token/delegation/AbstractDelegationTokenSecretManager.java
index fda62bf4ec6..7ed13ff067c 100644
--- a/src/java/org/apache/hadoop/security/token/delegation/AbstractDelegationTokenSecretManager.java
+++ b/src/java/org/apache/hadoop/security/token/delegation/AbstractDelegationTokenSecretManager.java
@@ -95,11 +95,13 @@ extends AbstractDelegationTokenIdentifier>
   }
 
   /** should be called before this object is used */
-  public synchronized void startThreads() throws IOException {
+  public void startThreads() throws IOException {
     updateCurrentKey();
-    running = true;
-    tokenRemoverThread = new Daemon(new ExpiredTokenRemover());
-    tokenRemoverThread.start();
+    synchronized (this) {
+      running = true;
+      tokenRemoverThread = new Daemon(new ExpiredTokenRemover());
+      tokenRemoverThread.start();
+    }
   }
   
   /**