diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index 2c6459ea8f6..de6e0e8426d 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -55,6 +55,9 @@ Release 2.0.4-beta - UNRELEASED
     HADOOP-7487. DF should throw a more reasonable exception when mount cannot
     be determined. (Andrew Wang via atm)
 
+    HADOOP-8917. add LOCALE.US to toLowerCase in SecurityUtil.replacePattern.
+    (Arpit Agarwal via suresh)
+
 Release 2.0.3-alpha - 2013-02-06 
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/SecurityUtil.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/SecurityUtil.java
index e900acfeaab..08dfaa1f064 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/SecurityUtil.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/SecurityUtil.java
@@ -30,6 +30,7 @@
 import java.security.PrivilegedExceptionAction;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Locale;
 import java.util.ServiceLoader;
 import java.util.Set;
 
@@ -219,7 +220,7 @@ private static String replacePattern(String[] components, String hostname)
     if (fqdn == null || fqdn.equals("") || fqdn.equals("0.0.0.0")) {
       fqdn = getLocalHostName();
     }
-    return components[0] + "/" + fqdn.toLowerCase() + "@" + components[2];
+    return components[0] + "/" + fqdn.toLowerCase(Locale.US) + "@" + components[2];
   }
   
   static String getLocalHostName() throws UnknownHostException {