/*
* Licensed to the Apache Software Foundation (ASF) under one or more contributor license
* agreements. See the NOTICE file distributed with this work for additional information regarding
* copyright ownership. The ASF licenses this file to You under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the License. You may obtain a
* copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package org.apache.geode.distributed.internal.deadlock;
import static org.junit.Assert.*;
import java.io.Serializable;
import java.util.Collections;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Set;
import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import org.junit.After;
import org.junit.Before;
import org.junit.Ignore;
import org.junit.Test;
import org.junit.experimental.categories.Category;
import org.apache.geode.test.junit.categories.IntegrationTest;
/**
* TODO: can we get rid of the Thread.sleep calls?
*/
@Category(IntegrationTest.class)
public class DeadlockDetectorIntegrationTest {
private volatile Set<Thread> stuckThreads;
@Before
public void setUp() throws Exception {
stuckThreads = Collections.synchronizedSet(new HashSet<Thread>());
}
/**
* IntegrationTests are forkEvery 1 so cleanup is not necessary
*/
@After
public void tearDown() throws Exception {
for (Thread thread : stuckThreads) {
thread.interrupt();
}
stuckThreads.clear();
}
/**
* must be IntegrationTest because: "we can't clean up the threads deadlocked on monitors"
*/
@Test
public void testMonitorDeadlock() throws Exception {
final Object lock1 = new Object();
final Object lock2 = new Object();
Thread thread1 = new Thread() {
public void run() {
stuckThreads.add(Thread.currentThread());
synchronized (lock1) {
Thread thread2 = new Thread() {
public void run() {
stuckThreads.add(Thread.currentThread());
synchronized (lock2) {
synchronized (lock1) {
System.out.println("we won't get here");
}
}
}
};
thread2.start();
try {
Thread.sleep(1000);
synchronized (lock2) {
System.out.println("We won't get here");
}
} catch (InterruptedException ignore) {
}
}
}
};
thread1.start();
Thread.sleep(2000);
DeadlockDetector detector = new DeadlockDetector();
detector.addDependencies(DeadlockDetector.collectAllDependencies("here"));
LinkedList<Dependency> deadlocks = detector.findDeadlock();
System.out.println("deadlocks=" + DeadlockDetector.prettyFormat(deadlocks));
assertEquals(4, detector.findDeadlock().size());
}
/**
* Make sure that we can detect a deadlock between two threads that are trying to acquire a two
* different syncs in the different orders.
*/
@Test
public void testSyncDeadlock() throws Exception {
final Lock lock1 = new ReentrantLock();
final Lock lock2 = new ReentrantLock();
Thread thread1 = new Thread() {
public void run() {
stuckThreads.add(Thread.currentThread());
lock1.lock();
Thread thread2 = new Thread() {
public void run() {
stuckThreads.add(Thread.currentThread());
lock2.lock();
try {
lock1.tryLock(10, TimeUnit.SECONDS);
} catch (InterruptedException e) {
// ignore
}
lock2.unlock();
}
};
thread2.start();
try {
Thread.sleep(1000);
lock2.tryLock(10, TimeUnit.SECONDS);
} catch (InterruptedException ignore) {
}
lock1.unlock();
}
};
thread1.start();
Thread.sleep(2000);
DeadlockDetector detector = new DeadlockDetector();
detector.addDependencies(DeadlockDetector.collectAllDependencies("here"));
LinkedList<Dependency> deadlocks = detector.findDeadlock();
System.out.println("deadlocks=" + DeadlockDetector.prettyFormat(deadlocks));
assertEquals(4, detector.findDeadlock().size());
}
@Ignore("Semaphore deadlock detection is not supported by the JDK")
@Test
public void testSemaphoreDeadlock() throws Exception {
final Semaphore lock1 = new Semaphore(1);
final Semaphore lock2 = new Semaphore(1);
Thread thread1 = new Thread() {
public void run() {
stuckThreads.add(Thread.currentThread());
try {
lock1.acquire();
} catch (InterruptedException e1) {
e1.printStackTrace();
}
Thread thread2 = new Thread() {
public void run() {
stuckThreads.add(Thread.currentThread());
try {
lock2.acquire();
lock1.tryAcquire(10, TimeUnit.SECONDS);
} catch (InterruptedException ignore) {
}
lock2.release();
}
};
thread2.start();
try {
Thread.sleep(1000);
lock2.tryAcquire(10, TimeUnit.SECONDS);
} catch (InterruptedException ignore) {
}
lock1.release();
}
};
thread1.start();
Thread.sleep(2000);
DeadlockDetector detector = new DeadlockDetector();
detector.addDependencies(DeadlockDetector.collectAllDependencies("here"));
LinkedList<Dependency> deadlocks = detector.findDeadlock();
System.out.println("deadlocks=" + DeadlockDetector.prettyFormat(deadlocks));
assertEquals(4, detector.findDeadlock().size());
}
@Ignore("ReadWriteLock deadlock detection is not currently supported by DeadlockDetector")
@Test
public void testReadLockDeadlock() throws Exception {
final ReadWriteLock lock1 = new ReentrantReadWriteLock();
final ReadWriteLock lock2 = new ReentrantReadWriteLock();
Thread thread1 = new Thread() {
@Override
public void run() {
stuckThreads.add(Thread.currentThread());
lock1.readLock().lock();
Thread thread2 = new Thread() {
@Override
public void run() {
stuckThreads.add(Thread.currentThread());
lock2.readLock().lock();
try {
lock1.writeLock().tryLock(10, TimeUnit.SECONDS);
} catch (InterruptedException ignore) {
}
lock2.readLock().unlock();
}
};
thread2.start();
try {
Thread.sleep(1000);
lock2.writeLock().tryLock(10, TimeUnit.SECONDS);
} catch (InterruptedException ignore) {
}
lock1.readLock().unlock();
}
};
thread1.start();
Thread.sleep(2000);
DeadlockDetector detector = new DeadlockDetector();
detector.addDependencies(DeadlockDetector.collectAllDependencies("here"));
LinkedList<Dependency> deadlocks = detector.findDeadlock();
System.out.println("deadlocks=" + deadlocks);
assertEquals(4, detector.findDeadlock().size());
}
/**
* A fake dependency monitor.
*/
private static class MockDependencyMonitor implements DependencyMonitor {
Set<Dependency<Thread, Serializable>> blockedThreads = new HashSet<>();
Set<Dependency<Serializable, Thread>> held = new HashSet<>();
@Override
public Set<Dependency<Thread, Serializable>> getBlockedThreads(Thread[] allThreads) {
return blockedThreads;
}
public void addDependency(String resource, Thread thread) {
held.add(new Dependency<>(resource, thread));
}
public void addDependency(Thread thread, String resource) {
blockedThreads.add(new Dependency<>(thread, resource));
}
@Override
public Set<Dependency<Serializable, Thread>> getHeldResources(Thread[] allThreads) {
return held;
}
}
}