diff --git a/CHANGES.txt b/CHANGES.txt
index 6a1c958d44..80e8640a84 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -306,6 +306,9 @@ Trunk (unreleased changes)
     HADOOP-6758. MapFile.fix does not allow index interval definition.
     (Gianmarco De Francisci Morales via tomwhite)
 
+    HADOOP-6926. SocketInputStream incorrectly implements read().
+    (Todd Lipcon via tomwhite)
+
 Release 0.21.1 - Unreleased
 
   IMPROVEMENTS
diff --git a/src/java/org/apache/hadoop/net/SocketInputStream.java b/src/java/org/apache/hadoop/net/SocketInputStream.java
index 2efe765cd8..ef8c02b7dd 100644
--- a/src/java/org/apache/hadoop/net/SocketInputStream.java
+++ b/src/java/org/apache/hadoop/net/SocketInputStream.java
@@ -119,7 +119,7 @@ public int read() throws IOException {
     byte[] buf = new byte[1];
     int ret = read(buf, 0, 1);
     if (ret > 0) {
-      return (byte)buf[0];
+      return (int)(buf[0] & 0xff);
     }
     if (ret != -1) {
       // unexpected
diff --git a/src/test/core/org/apache/hadoop/net/TestSocketIOWithTimeout.java b/src/test/core/org/apache/hadoop/net/TestSocketIOWithTimeout.java
index 53f320917c..0c887eb82b 100644
--- a/src/test/core/org/apache/hadoop/net/TestSocketIOWithTimeout.java
+++ b/src/test/core/org/apache/hadoop/net/TestSocketIOWithTimeout.java
@@ -101,12 +101,15 @@ public void testSocketIOWithTimeout() throws IOException {
       
       byte[] writeBytes = TEST_STRING.getBytes();
       byte[] readBytes = new byte[writeBytes.length];
+      byte byteWithHighBit = (byte)0x80;
       
       out.write(writeBytes);
+      out.write(byteWithHighBit);
       doIO(null, out);
       
       in.read(readBytes);
       assertTrue(Arrays.equals(writeBytes, readBytes));
+      assertEquals(byteWithHighBit & 0xff, in.read());
       doIO(in, null);
       
       /*