undefect. CWE-407 — 63 sites patched across 27 ecosystems

Authors: russell@unturf.com · brackishbert@gmail.com · foxhop.net · TimeHexOn.com

Patches, unit tests, benchmarks, whitepaper, and outreach briefs.
Public domain — no copyright claimed. Use freely.

test/jdk/java/lang/management/ThreadMXBean/SynchronizerDeadlock.java

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+/*
+ * Copyright (c) 2005, 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.
+ */
+
+/*
+ * @summary SynchronizerDeadlock creates threads that are deadlocked
+ *          waiting for JSR-166 synchronizers.
+ * @author  Mandy Chung
+ * @build Barrier
+ */
+
+import java.lang.management.*;
+import java.util.*;
+import java.util.concurrent.locks.*;
+
+public class SynchronizerDeadlock {
+
+    private Lock a = new ReentrantLock();
+    private Lock b = new ReentrantLock();
+    private Lock c = new ReentrantLock();
+    private final int EXPECTED_THREADS = 3;
+    private Thread[] dThreads = new Thread[EXPECTED_THREADS];
+    private Barrier go = new Barrier(1);
+    private Barrier barr = new Barrier(EXPECTED_THREADS);
+
+    public SynchronizerDeadlock() {
+        dThreads[0] = new DeadlockingThread("Deadlock-Thread-1", a, b);
+        dThreads[1] = new DeadlockingThread("Deadlock-Thread-2", b, c);
+        dThreads[2] = new DeadlockingThread("Deadlock-Thread-3", c, a);
+
+        // make them daemon threads so that the test will exit
+        for (int i = 0; i < EXPECTED_THREADS; i++) {
+            dThreads[i].setDaemon(true);
+            dThreads[i].start();
+        }
+    }
+
+    void goDeadlock() {
+        // Wait until all threads have started
+        barr.await();
+
+        // reset for later signals
+        barr.set(EXPECTED_THREADS);
+
+        while (go.getWaiterCount() != EXPECTED_THREADS) {
+            synchronized(this) {
+                try {
+                    wait(100);
+                } catch (InterruptedException e) {
+                    // ignore
+                }
+            }
+        }
+
+        // sleep a little so that all threads are blocked before notified.
+        try {
+            Thread.sleep(100);
+        } catch (InterruptedException e) {
+            // ignore
+        }
+        go.signal();
+
+    }
+
+    void waitUntilDeadlock() {
+        barr.await();
+
+        for (int i=0; i < 100; i++) {
+            // sleep a little while to wait until threads are blocked.
+            try {
+                Thread.sleep(100);
+            } catch (InterruptedException e) {
+                // ignore
+            }
+            boolean retry = false;
+            for (Thread t: dThreads) {
+                if (t.getState() == Thread.State.RUNNABLE) {
+                    retry = true;
+                    break;
+                }
+            }
+            if (!retry) {
+                break;
+            }
+        }
+    }
+
+    private class DeadlockingThread extends Thread {
+        private final Lock lock1;
+        private final Lock lock2;
+
+        DeadlockingThread(String name, Lock lock1, Lock lock2) {
+            super(name);
+            this.lock1 = lock1;
+            this.lock2 = lock2;
+        }
+        public void run() {
+            f();
+        }
+        private void f() {
+            lock1.lock();
+            try {
+                barr.signal();
+                go.await();
+                g();
+            } finally {
+                lock1.unlock();
+            }
+        }
+        private void g() {
+            barr.signal();
+            lock2.lock();
+            throw new RuntimeException("should not reach here.");
+        }
+    }
+
+    void checkResult(long[] threads) {
+        if (threads.length != EXPECTED_THREADS) {
+            ThreadDump.threadDump();
+            throw new RuntimeException("Expected to have " +
+                EXPECTED_THREADS + " to be in the deadlock list");
+        }
+        boolean[] found = new boolean[EXPECTED_THREADS];
+        for (int i = 0; i < threads.length; i++) {
+            for (int j = 0; j < dThreads.length; j++) {
+                if (dThreads[j].getId() == threads[i]) {
+                    found[j] = true;
+                }
+            }
+        }
+        boolean ok = true;
+        for (int j = 0; j < found.length; j++) {
+            ok = ok && found[j];
+        }
+
+        if (!ok) {
+            System.out.print("Returned result is [");
+            for (int j = 0; j < threads.length; j++) {
+                System.out.print(threads[j] + " ");
+            }
+            System.out.println("]");
+
+            System.out.print("Expected result is [");
+            for (int j = 0; j < threads.length; j++) {
+                System.out.print(dThreads[j] + " ");
+            }
+            System.out.println("]");
+            throw new RuntimeException("Unexpected result returned " +
+                " by findMonitorDeadlockedThreads method.");
+        }
+    }
+}