From 8099de259fb91a29674bf17cb1382c038b707a90 Mon Sep 17 00:00:00 2001
From: Colin Patrick Mccabe <cmccabe@cloudera.com>
Date: Mon, 6 Oct 2014 14:40:41 -0700
Subject: [PATCH] HADOOP-10404. Some accesses to DomainSocketWatcher#closed are
 not protected by the lock (cmccabe)

---
 hadoop-common-project/hadoop-common/CHANGES.txt             | 3 +++
 .../org/apache/hadoop/net/unix/DomainSocketWatcher.java     | 6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index 21f4d0881f8..2d27e7ccfbe 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -354,6 +354,9 @@ Release 2.7.0 - UNRELEASED
 
   BUG FIXES
 
+    HADOOP-10404. Some accesses to DomainSocketWatcher#closed are not protected
+    by the lock (cmccabe)
+
 Release 2.6.0 - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/unix/DomainSocketWatcher.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/unix/DomainSocketWatcher.java
index 8348aeb7dcf..6215e58cafd 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/unix/DomainSocketWatcher.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/net/unix/DomainSocketWatcher.java
@@ -101,6 +101,7 @@ public final class DomainSocketWatcher implements Closeable {
    */
   private class NotificationHandler implements Handler {
     public boolean handle(DomainSocket sock) {
+      lock.lock();
       try {
         if (LOG.isTraceEnabled()) {
           LOG.trace(this + ": NotificationHandler: doing a read on " +
@@ -124,6 +125,8 @@ public final class DomainSocketWatcher implements Closeable {
         }
         closed = true;
         return true;
+      } finally {
+        lock.unlock();
       }
     }
   }
@@ -346,12 +349,15 @@ public final class DomainSocketWatcher implements Closeable {
    * Wake up the DomainSocketWatcher thread.
    */
   private void kick() {
+    lock.lock();
     try {
       notificationSockets[0].getOutputStream().write(0);
     } catch (IOException e) {
       if (!closed) {
         LOG.error(this + ": error writing to notificationSockets[0]", e);
       }
+    } finally {
+      lock.unlock();
     }
   }