diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index 47968d336ce..6fc6dcbc17a 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -644,6 +644,9 @@ Release 2.0.5-beta - UNRELEASED
 
     HADOOP-9473. Typo in FileUtil copy() method. (Glen Mazza via suresh)
 
+    HADOOP-9504. MetricsDynamicMBeanBase has concurrency issues in
+    createMBeanInfo (Liang Xie via jlowe)
+
 Release 2.0.4-alpha - UNRELEASED
 
   INCOMPATIBLE CHANGES
@@ -1657,6 +1660,9 @@ Release 0.23.8 - UNRELEASED
     HADOOP-9469. mapreduce/yarn source jars not included in dist tarball
     (Robert Parker via tgraves)
 
+    HADOOP-9504. MetricsDynamicMBeanBase has concurrency issues in
+    createMBeanInfo (Liang Xie via jlowe)
+
 Release 0.23.7 - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsDynamicMBeanBase.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsDynamicMBeanBase.java
index ea663a45b37..57014d5781b 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsDynamicMBeanBase.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsDynamicMBeanBase.java
@@ -18,9 +18,9 @@
 package org.apache.hadoop.metrics.util;
 
 import java.util.ArrayList;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
 import javax.management.Attribute;
 import javax.management.AttributeList;
@@ -69,6 +69,7 @@ public abstract class MetricsDynamicMBeanBase implements DynamicMBean {
   protected MetricsDynamicMBeanBase(final MetricsRegistry mr, final String aMBeanDescription) {
     metricsRegistry = mr;
     mbeanDescription = aMBeanDescription;
+    metricsRateAttributeMod = new ConcurrentHashMap<String, MetricsBase>();
     createMBeanInfo();
   }
   
@@ -78,7 +79,6 @@ public abstract class MetricsDynamicMBeanBase implements DynamicMBean {
   }
   
   private void createMBeanInfo() {
-    metricsRateAttributeMod = new HashMap<String, MetricsBase>();
     boolean needsMinMaxResetOperation = false;
     List<MBeanAttributeInfo> attributesInfo = new ArrayList<MBeanAttributeInfo>();
     MBeanOperationInfo[] operationsInfo = null;