diff --git a/hadoop-yarn-project/CHANGES.txt b/hadoop-yarn-project/CHANGES.txt
index bbda48d15ac..d0cbcd29cec 100644
--- a/hadoop-yarn-project/CHANGES.txt
+++ b/hadoop-yarn-project/CHANGES.txt
@@ -450,6 +450,9 @@ Release 2.6.0 - UNRELEASED
     YARN-2523. ResourceManager UI showing negative value for "Decommissioned
     Nodes" field (Rohith via jlowe)
 
+    YARN-2608. FairScheduler: Potential deadlocks in loading alloc files and 
+    clock access. (Wei Yan via kasha)
+
 Release 2.5.1 - 2014-09-05
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FairScheduler.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FairScheduler.java
index 296d8844373..d6339813487 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FairScheduler.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FairScheduler.java
@@ -117,7 +117,7 @@ public class FairScheduler extends
 
   private Resource incrAllocation;
   private QueueManager queueMgr;
-  private Clock clock;
+  private volatile Clock clock;
   private boolean usePortForNodeName;
 
   private static final Log LOG = LogFactory.getLog(FairScheduler.class);
@@ -555,11 +555,12 @@ public class FairScheduler extends
     return continuousSchedulingSleepMs;
   }
 
-  public synchronized Clock getClock() {
+  public Clock getClock() {
     return clock;
   }
 
-  protected synchronized void setClock(Clock clock) {
+  @VisibleForTesting
+  void setClock(Clock clock) {
     this.clock = clock;
   }
 
@@ -1204,64 +1205,65 @@ public class FairScheduler extends
     this.rmContext = rmContext;
   }
 
-  private synchronized void initScheduler(Configuration conf)
-      throws IOException {
-    this.conf = new FairSchedulerConfiguration(conf);
-    validateConf(this.conf);
-    minimumAllocation = this.conf.getMinimumAllocation();
-    maximumAllocation = this.conf.getMaximumAllocation();
-    incrAllocation = this.conf.getIncrementAllocation();
-    continuousSchedulingEnabled = this.conf.isContinuousSchedulingEnabled();
-    continuousSchedulingSleepMs =
-        this.conf.getContinuousSchedulingSleepMs();
-    nodeLocalityThreshold = this.conf.getLocalityThresholdNode();
-    rackLocalityThreshold = this.conf.getLocalityThresholdRack();
-    nodeLocalityDelayMs = this.conf.getLocalityDelayNodeMs();
-    rackLocalityDelayMs = this.conf.getLocalityDelayRackMs();
-    preemptionEnabled = this.conf.getPreemptionEnabled();
-    preemptionUtilizationThreshold =
-        this.conf.getPreemptionUtilizationThreshold();
-    assignMultiple = this.conf.getAssignMultiple();
-    maxAssign = this.conf.getMaxAssign();
-    sizeBasedWeight = this.conf.getSizeBasedWeight();
-    preemptionInterval = this.conf.getPreemptionInterval();
-    waitTimeBeforeKill = this.conf.getWaitTimeBeforeKill();
-    usePortForNodeName = this.conf.getUsePortForNodeName();
+  private void initScheduler(Configuration conf) throws IOException {
+    synchronized (this) {
+      this.conf = new FairSchedulerConfiguration(conf);
+      validateConf(this.conf);
+      minimumAllocation = this.conf.getMinimumAllocation();
+      maximumAllocation = this.conf.getMaximumAllocation();
+      incrAllocation = this.conf.getIncrementAllocation();
+      continuousSchedulingEnabled = this.conf.isContinuousSchedulingEnabled();
+      continuousSchedulingSleepMs =
+          this.conf.getContinuousSchedulingSleepMs();
+      nodeLocalityThreshold = this.conf.getLocalityThresholdNode();
+      rackLocalityThreshold = this.conf.getLocalityThresholdRack();
+      nodeLocalityDelayMs = this.conf.getLocalityDelayNodeMs();
+      rackLocalityDelayMs = this.conf.getLocalityDelayRackMs();
+      preemptionEnabled = this.conf.getPreemptionEnabled();
+      preemptionUtilizationThreshold =
+          this.conf.getPreemptionUtilizationThreshold();
+      assignMultiple = this.conf.getAssignMultiple();
+      maxAssign = this.conf.getMaxAssign();
+      sizeBasedWeight = this.conf.getSizeBasedWeight();
+      preemptionInterval = this.conf.getPreemptionInterval();
+      waitTimeBeforeKill = this.conf.getWaitTimeBeforeKill();
+      usePortForNodeName = this.conf.getUsePortForNodeName();
 
-    updateInterval = this.conf.getUpdateInterval();
-    if (updateInterval < 0) {
-      updateInterval = FairSchedulerConfiguration.DEFAULT_UPDATE_INTERVAL_MS;
-      LOG.warn(FairSchedulerConfiguration.UPDATE_INTERVAL_MS
-              + " is invalid, so using default value " +
-              + FairSchedulerConfiguration.DEFAULT_UPDATE_INTERVAL_MS
-              + " ms instead");
-    }
+      updateInterval = this.conf.getUpdateInterval();
+      if (updateInterval < 0) {
+        updateInterval = FairSchedulerConfiguration.DEFAULT_UPDATE_INTERVAL_MS;
+        LOG.warn(FairSchedulerConfiguration.UPDATE_INTERVAL_MS
+            + " is invalid, so using default value " +
+            +FairSchedulerConfiguration.DEFAULT_UPDATE_INTERVAL_MS
+            + " ms instead");
+      }
 
-    rootMetrics = FSQueueMetrics.forQueue("root", null, true, conf);
-    fsOpDurations = FSOpDurations.getInstance(true);
+      rootMetrics = FSQueueMetrics.forQueue("root", null, true, conf);
+      fsOpDurations = FSOpDurations.getInstance(true);
 
-    // This stores per-application scheduling information
-    this.applications = new ConcurrentHashMap<
-        ApplicationId, SchedulerApplication<FSAppAttempt>>();
-    this.eventLog = new FairSchedulerEventLog();
-    eventLog.init(this.conf);
+      // This stores per-application scheduling information
+      this.applications = new ConcurrentHashMap<
+          ApplicationId, SchedulerApplication<FSAppAttempt>>();
+      this.eventLog = new FairSchedulerEventLog();
+      eventLog.init(this.conf);
 
-    allocConf = new AllocationConfiguration(conf);
-    try {
-      queueMgr.initialize(conf);
-    } catch (Exception e) {
-      throw new IOException("Failed to start FairScheduler", e);
-    }
+      allocConf = new AllocationConfiguration(conf);
+      try {
+        queueMgr.initialize(conf);
+      } catch (Exception e) {
+        throw new IOException("Failed to start FairScheduler", e);
+      }
 
-    updateThread = new UpdateThread();
-    updateThread.setName("FairSchedulerUpdateThread");
-    updateThread.setDaemon(true);
+      updateThread = new UpdateThread();
+      updateThread.setName("FairSchedulerUpdateThread");
+      updateThread.setDaemon(true);
 
-    if (continuousSchedulingEnabled) {
-      // start continuous scheduling thread
-      schedulingThread = new ContinuousSchedulingThread();
-      schedulingThread.setName("FairSchedulerContinuousScheduling");
-      schedulingThread.setDaemon(true);
+      if (continuousSchedulingEnabled) {
+        // start continuous scheduling thread
+        schedulingThread = new ContinuousSchedulingThread();
+        schedulingThread.setName("FairSchedulerContinuousScheduling");
+        schedulingThread.setDaemon(true);
+      }
     }
 
     allocsLoader.init(conf);
@@ -1321,7 +1323,7 @@ public class FairScheduler extends
   }
 
   @Override
-  public synchronized void reinitialize(Configuration conf, RMContext rmContext)
+  public void reinitialize(Configuration conf, RMContext rmContext)
       throws IOException {
     try {
       allocsLoader.reloadAllocations();