| /* |
| * Copyright (c) 2007, 2018, 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. |
| */ |
| package nsk.share.locks; |
| |
| import java.util.*; |
| import nsk.share.TestBug; |
| import nsk.share.Wicket; |
| |
| /* |
| * Class used to create deadlocked threads. It is possible create 2 or more deadlocked thread, also |
| * is is possible to specify resource of which type should lock each deadlocked thread |
| */ |
| public class DeadlockMaker { |
| // create deadlock with 2 threads |
| // lockType1 and lockType2 - type of locking resources used for deadlock creation |
| public static DeadlockedThread[] createDeadlockedThreads(LockType lockType1, LockType lockType2) { |
| DeadlockedThread[] resultThreads = new DeadlockedThread[2]; |
| |
| Wicket step1 = new Wicket(); |
| Wicket step2 = new Wicket(); |
| |
| Wicket readyWicket = new Wicket(2); |
| |
| DeadlockLocker locker1 = createLocker(lockType1, step1, step2, readyWicket); |
| DeadlockLocker locker2 = createLocker(lockType2, step2, step1, readyWicket); |
| locker1.setInner(locker2); |
| locker2.setInner(locker1); |
| |
| resultThreads[0] = new DeadlockedThread(locker1); |
| resultThreads[1] = new DeadlockedThread(locker2); |
| |
| resultThreads[0].start(); |
| resultThreads[1].start(); |
| |
| readyWicket.waitFor(); |
| |
| // additional check to be sure that all threads really blocked |
| waitForDeadlock(resultThreads); |
| |
| return resultThreads; |
| } |
| |
| // create deadlock with several threads |
| // locksTypes - type of locking resources used for deadlock creation |
| public static DeadlockedThread[] createDeadlockedThreads(List<LockType> locksTypes) { |
| if (locksTypes.size() < 2) { |
| throw new IllegalArgumentException("Need at least 2 threads for deadlock"); |
| } |
| |
| int threadsNumber = locksTypes.size(); |
| |
| DeadlockedThread[] resultThreads = new DeadlockedThread[threadsNumber]; |
| |
| Wicket readyWicket = new Wicket(threadsNumber); |
| |
| DeadlockLocker deadlockLockers[] = new DeadlockLocker[threadsNumber]; |
| Wicket stepWickets[] = new Wicket[threadsNumber]; |
| |
| for (int i = 0; i < threadsNumber; i++) |
| stepWickets[i] = new Wicket(); |
| |
| int index1 = 0; |
| int index2 = 1; |
| for (int i = 0; i < threadsNumber; i++) { |
| Wicket step1 = stepWickets[index1]; |
| Wicket step2 = stepWickets[index2]; |
| |
| deadlockLockers[i] = createLocker(locksTypes.get(i), step1, step2, readyWicket); |
| |
| if (i > 0) |
| deadlockLockers[i - 1].setInner(deadlockLockers[i]); |
| |
| index1 = (index1 + 1) % threadsNumber; |
| index2 = (index2 + 1) % threadsNumber; |
| } |
| deadlockLockers[threadsNumber - 1].setInner(deadlockLockers[0]); |
| |
| for (int i = 0; i < threadsNumber; i++) { |
| resultThreads[i] = new DeadlockedThread(deadlockLockers[i]); |
| resultThreads[i].start(); |
| } |
| |
| readyWicket.waitFor(); |
| |
| // additional check to be sure that all threads really blocked |
| waitForDeadlock(resultThreads); |
| |
| return resultThreads; |
| } |
| |
| /* |
| * Wait when thread state will change to be sure that deadlock is really created |
| */ |
| static private void waitForDeadlock(DeadlockedThread[] threads) { |
| Set<Thread.State> targetStates = new HashSet<Thread.State>(); |
| |
| // thread is waiting for a monitor lock to enter a synchronized block/method |
| targetStates.add(Thread.State.BLOCKED); |
| |
| // thread calls LockSupport.park |
| targetStates.add(Thread.State.WAITING); |
| |
| // thread calls LockSupport.parkNanos or LockSupport.parkUntil |
| targetStates.add(Thread.State.TIMED_WAITING); |
| |
| for (Thread thread : threads) { |
| while (!targetStates.contains(thread.getState())) { |
| sleep(100); |
| } |
| } |
| } |
| |
| static private void sleep(long millis) { |
| try { |
| Thread.sleep(millis); |
| } catch (InterruptedException e) { |
| System.out.println("Unexpected exception: " + e); |
| e.printStackTrace(System.out); |
| |
| TestBug testBugException = new TestBug("Unexpected exception was throw: " + e); |
| testBugException.initCause(e); |
| throw testBugException; |
| } |
| } |
| |
| // create locker with given type |
| public static DeadlockLocker createLocker(LockType type, Wicket step1, Wicket step2, Wicket readyWicket) { |
| switch (type) { |
| case SYNCHRONIZED_METHOD: |
| return new SynchronizedMethodLocker(step1, step2, readyWicket); |
| case SYNCHRONIZED_BLOCK: |
| return new SynchronizedBlockLocker(step1, step2, readyWicket); |
| case REENTRANT_LOCK: |
| return new ReentrantLockLocker(step1, step2, readyWicket); |
| case JNI_LOCK: |
| return new JNIMonitorLocker(step1, step2, readyWicket); |
| } |
| |
| throw new IllegalArgumentException("Unsupported lock type: " + type); |
| } |
| } |