--- a/jdk/src/share/classes/java/lang/ref/Reference.java	Thu Jul 11 17:52:04 2013 -0700
+++ b/jdk/src/share/classes/java/lang/ref/Reference.java	Mon Jul 08 14:05:59 2013 +0200
@@ -89,7 +89,7 @@
 
     private T referent;         /* Treated specially by GC */
 
-    ReferenceQueue<? super T> queue;
+    volatile ReferenceQueue<? super T> queue;
 
     /* When active:   NULL
      *     pending:   this
@@ -225,9 +225,7 @@
      *           been enqueued
      */
     public boolean isEnqueued() {
-        synchronized (this) {
-            return (this.next != null && this.queue == ReferenceQueue.ENQUEUED);
-        }
+        return (this.queue == ReferenceQueue.ENQUEUED);
     }
 
     /**

--- a/jdk/src/share/classes/java/lang/ref/ReferenceQueue.java	Thu Jul 11 17:52:04 2013 -0700
+++ b/jdk/src/share/classes/java/lang/ref/ReferenceQueue.java	Mon Jul 08 14:05:59 2013 +0200
@@ -55,25 +55,29 @@
     private long queueLength = 0;
 
     boolean enqueue(Reference<? extends T> r) { /* Called only by Reference class */
-        synchronized (r) {
-            if (r.queue == ENQUEUED) return false;
-            synchronized (lock) {
-                r.queue = ENQUEUED;
-                r.next = (head == null) ? r : head;
-                head = r;
-                queueLength++;
-                if (r instanceof FinalReference) {
-                    sun.misc.VM.addFinalRefCount(1);
-                }
-                lock.notifyAll();
-                return true;
+        synchronized (lock) {
+            // Check that since getting the lock this reference hasn't already been
+            // enqueued (and even then removed)
+            ReferenceQueue queue = r.queue;
+            if ((queue == NULL) || (queue == ENQUEUED)) {
+                return false;
             }
+            assert queue == this;
+            r.queue = ENQUEUED;
+            r.next = (head == null) ? r : head;
+            head = r;
+            queueLength++;
+            if (r instanceof FinalReference) {
+                sun.misc.VM.addFinalRefCount(1);
+            }
+            lock.notifyAll();
+            return true;
         }
     }
 
     private Reference<? extends T> reallyPoll() {       /* Must hold lock */
-        if (head != null) {
-            Reference<? extends T> r = head;
+        Reference<? extends T> r = head;
+        if (r != null) {
             head = (r.next == r) ? null : r.next;
             r.queue = NULL;
             r.next = r;

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/lang/ref/EnqueuePollRace.java	Mon Jul 08 14:05:59 2013 +0200
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/* @test
+ * @bug 8014890
+ * @summary Verify that a race between ReferenceQueue.enqueue() and poll() does not occur.
+ * @author thomas.schatzl@oracle.com
+ * @run main/othervm -XX:+UseSerialGC -Xmx10M EnqueuePollRace
+ */
+
+import java.lang.ref.*;
+
+public class EnqueuePollRace {
+
+    public static void main(String args[]) throws Exception {
+        new WeakRef().run();
+        System.out.println("Test passed.");
+    }
+
+    static class WeakRef {
+        ReferenceQueue<Object> queue = new ReferenceQueue<Object>();
+        final int numReferences = 100;
+        final Reference refs[] = new Reference[numReferences];
+        final int iterations = 1000;
+
+        void run() throws InterruptedException {
+            for (int i = 0; i < iterations; i++) {
+                queue = new ReferenceQueue<Object>();
+
+                for (int j = 0; j < refs.length; j++) {
+                    refs[j] = new WeakReference(new Object(), queue);
+                }
+
+                System.gc(); // enqueues references into the list of discovered references
+
+                // now manually enqueue all of them
+                for (int j = 0; j < refs.length; j++) {
+                    refs[j].enqueue();
+                }
+                // and get them back. There should be exactly numReferences
+                // entries in the queue now.
+                int foundReferences = 0;
+                while (queue.poll() != null) {
+                    foundReferences++;
+                }
+
+                if (foundReferences != refs.length) {
+                    throw new RuntimeException("Got " + foundReferences + " references in the queue, but expected " + refs.length);
+                }
+            }
+        }
+    }
+}