# HG changeset patch

# User adinn

# Date 1487931564 0

#      Fri Feb 24 10:19:24 2017 +0000

# Node ID d41592af9af3790fe5eee30ce686d85cff09c942

# Parent  1ac9b0f1bf17fc5935bfa8250550eabc2ffb6785

8174729, PR3336, RH1420518: Race Condition in java.lang.reflect.WeakCache

Summary: Race can occur between Proxy.getProxyClass and Proxy.isProxyClass

Reviewed-by: mchung

diff --git a/src/share/classes/java/lang/reflect/WeakCache.java b/src/share/classes/java/lang/reflect/WeakCache.java

--- openjdk/jdk/src/share/classes/java/lang/reflect/WeakCache.java

+++ openjdk/jdk/src/share/classes/java/lang/reflect/WeakCache.java

@@ -239,11 +239,11 @@

             // wrap value with CacheValue (WeakReference)

             CacheValue<V> cacheValue = new CacheValue<>(value);

+            // put into reverseMap

+            reverseMap.put(cacheValue, Boolean.TRUE);

+

             // try replacing us with CacheValue (this should always succeed)

-            if (valuesMap.replace(subKey, this, cacheValue)) {

-                // put also in reverseMap

-                reverseMap.put(cacheValue, Boolean.TRUE);

-            } else {

+            if (!valuesMap.replace(subKey, this, cacheValue)) {

                 throw new AssertionError("Should not reach here");

             }

diff --git a/test/java/lang/reflect/Proxy/ProxyRace.java b/test/java/lang/reflect/Proxy/ProxyRace.java

new file mode 100644

--- /dev/null

+++ openjdk/jdk/test/java/lang/reflect/Proxy/ProxyRace.java

@@ -0,0 +1,88 @@

+/*

+ * Copyright (c) 2017, 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.

+ */

+

+import java.lang.reflect.Proxy;

+import java.util.concurrent.ExecutorService;

+import java.util.concurrent.Executors;

+import java.util.concurrent.Phaser;

+import java.util.concurrent.TimeUnit;

+import java.util.concurrent.atomic.AtomicInteger;

+

+/**

+ * @test

+ * @bug 8174729

+ * @summary Proxy.getProxyClass() / Proxy.isProxyClass() race detector

+ * @run main ProxyRace

+ * @author plevart

+ */

+

+public class ProxyRace {

+

+    static final int threads = 8;

+

+    static volatile ClassLoader classLoader;

+    static volatile boolean terminate;

+    static final AtomicInteger racesDetected = new AtomicInteger();

+

+    public static void main(String[] args) throws Exception {

+

+        Phaser phaser = new Phaser(threads) {

+            @Override

+            protected boolean onAdvance(int phase, int registeredParties) {

+                // install new ClassLoader on each advance

+                classLoader = new CL();

+                return terminate;

+            }

+        };

+

+        ExecutorService exe = Executors.newFixedThreadPool(threads);

+

+        for (int i = 0; i < threads; i++) {

+            exe.execute(() -> {

+                while (phaser.arriveAndAwaitAdvance() >= 0) {

+                    Class proxyClass = Proxy.getProxyClass(classLoader, Runnable.class);

+                    if (!Proxy.isProxyClass(proxyClass)) {

+                        racesDetected.incrementAndGet();

+                    }

+                }

+            });

+        }

+

+        Thread.sleep(5000L);

+

+        terminate = true;

+        exe.shutdown();

+        exe.awaitTermination(5L, TimeUnit.SECONDS);

+

+        System.out.println(racesDetected.get() + " races detected");

+        if (racesDetected.get() != 0) {

+            throw new RuntimeException(racesDetected.get() + " races detected");

+        }

+    }

+

+    static class CL extends ClassLoader {

+        public CL() {

+            super(ClassLoader.getSystemClassLoader());

+        }

+    }

+}