J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2005 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. |
| 8 | * |
| 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 12 | * version 2 for more details (a copy is included in the LICENSE file that |
| 13 | * accompanied this code). |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License version |
| 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 18 | * |
| 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 21 | * have any questions. |
| 22 | */ |
| 23 | |
| 24 | /* |
| 25 | * @summary SynchronizerDeadlock creates threads that are deadlocked |
| 26 | * waiting for JSR-166 synchronizers. |
| 27 | * @author Mandy Chung |
| 28 | * @build Barrier |
| 29 | */ |
| 30 | |
| 31 | import java.lang.management.*; |
| 32 | import java.util.*; |
| 33 | import java.util.concurrent.locks.*; |
| 34 | |
| 35 | public class SynchronizerDeadlock { |
| 36 | |
| 37 | private Lock a = new ReentrantLock(); |
| 38 | private Lock b = new ReentrantLock(); |
| 39 | private Lock c = new ReentrantLock(); |
| 40 | private final int EXPECTED_THREADS = 3; |
| 41 | private Thread[] dThreads = new Thread[EXPECTED_THREADS]; |
| 42 | private Barrier go = new Barrier(1); |
| 43 | private Barrier barr = new Barrier(EXPECTED_THREADS); |
| 44 | |
| 45 | public SynchronizerDeadlock() { |
| 46 | dThreads[0] = new DeadlockingThread("Deadlock-Thread-1", a, b); |
| 47 | dThreads[1] = new DeadlockingThread("Deadlock-Thread-2", b, c); |
| 48 | dThreads[2] = new DeadlockingThread("Deadlock-Thread-3", c, a); |
| 49 | |
| 50 | // make them daemon threads so that the test will exit |
| 51 | for (int i = 0; i < EXPECTED_THREADS; i++) { |
| 52 | dThreads[i].setDaemon(true); |
| 53 | dThreads[i].start(); |
| 54 | } |
| 55 | } |
| 56 | |
| 57 | void goDeadlock() { |
| 58 | // Wait until all threads have started |
| 59 | barr.await(); |
| 60 | |
| 61 | // reset for later signals |
| 62 | barr.set(EXPECTED_THREADS); |
| 63 | |
| 64 | while (go.getWaiterCount() != EXPECTED_THREADS) { |
| 65 | synchronized(this) { |
| 66 | try { |
| 67 | wait(100); |
| 68 | } catch (InterruptedException e) { |
| 69 | // ignore |
| 70 | } |
| 71 | } |
| 72 | } |
| 73 | |
| 74 | // sleep a little so that all threads are blocked before notified. |
| 75 | try { |
| 76 | Thread.sleep(100); |
| 77 | } catch (InterruptedException e) { |
| 78 | // ignore |
| 79 | } |
| 80 | go.signal(); |
| 81 | |
| 82 | } |
| 83 | |
| 84 | void waitUntilDeadlock() { |
| 85 | barr.await(); |
| 86 | // sleep a little while to wait until threads are blocked. |
| 87 | try { |
| 88 | Thread.sleep(100); |
| 89 | } catch (InterruptedException e) { |
| 90 | // ignore |
| 91 | } |
| 92 | } |
| 93 | |
| 94 | private class DeadlockingThread extends Thread { |
| 95 | private final Lock lock1; |
| 96 | private final Lock lock2; |
| 97 | |
| 98 | DeadlockingThread(String name, Lock lock1, Lock lock2) { |
| 99 | super(name); |
| 100 | this.lock1 = lock1; |
| 101 | this.lock2 = lock2; |
| 102 | } |
| 103 | public void run() { |
| 104 | f(); |
| 105 | } |
| 106 | private void f() { |
| 107 | lock1.lock(); |
| 108 | try { |
| 109 | barr.signal(); |
| 110 | go.await(); |
| 111 | g(); |
| 112 | } finally { |
| 113 | lock1.unlock(); |
| 114 | } |
| 115 | } |
| 116 | private void g() { |
| 117 | barr.signal(); |
| 118 | lock2.lock(); |
| 119 | throw new RuntimeException("should not reach here."); |
| 120 | } |
| 121 | } |
| 122 | |
| 123 | void checkResult(long[] threads) { |
| 124 | if (threads.length != EXPECTED_THREADS) { |
| 125 | ThreadDump.threadDump(); |
| 126 | throw new RuntimeException("Expected to have " + |
| 127 | EXPECTED_THREADS + " to be in the deadlock list"); |
| 128 | } |
| 129 | boolean[] found = new boolean[EXPECTED_THREADS]; |
| 130 | for (int i = 0; i < threads.length; i++) { |
| 131 | for (int j = 0; j < dThreads.length; j++) { |
| 132 | if (dThreads[j].getId() == threads[i]) { |
| 133 | found[j] = true; |
| 134 | } |
| 135 | } |
| 136 | } |
| 137 | boolean ok = true; |
| 138 | for (int j = 0; j < found.length; j++) { |
| 139 | ok = ok && found[j]; |
| 140 | } |
| 141 | |
| 142 | if (!ok) { |
| 143 | System.out.print("Returned result is ["); |
| 144 | for (int j = 0; j < threads.length; j++) { |
| 145 | System.out.print(threads[j] + " "); |
| 146 | } |
| 147 | System.out.println("]"); |
| 148 | |
| 149 | System.out.print("Expected result is ["); |
| 150 | for (int j = 0; j < threads.length; j++) { |
| 151 | System.out.print(dThreads[j] + " "); |
| 152 | } |
| 153 | System.out.println("]"); |
| 154 | throw new RuntimeException("Unexpected result returned " + |
| 155 | " by findMonitorDeadlockedThreads method."); |
| 156 | } |
| 157 | } |
| 158 | } |