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/*
* Copyright (c) 2022, 2023, 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.
*/
/**
* @test id=default
* @bug 8284161 8287103
* @summary Test ThredMXBean.findMonitorDeadlockedThreads with cycles of
* platform and virtual threads in deadlock
* @modules java.base/java.lang:+open java.management
* @library /test/lib
* @run main/othervm VirtualThreadDeadlocks PP
* @run main/othervm VirtualThreadDeadlocks PV
* @run main/othervm VirtualThreadDeadlocks VV
*/
/**
* @test id=no-vmcontinuations
* @requires vm.continuations
* @modules java.base/java.lang:+open java.management
* @library /test/lib
* @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:-VMContinuations VirtualThreadDeadlocks PP
* @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:-VMContinuations VirtualThreadDeadlocks PV
* @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:-VMContinuations VirtualThreadDeadlocks VV
*/
import java.lang.management.ManagementFactory;
import java.lang.management.ThreadMXBean;
import java.util.Arrays;
import java.util.concurrent.CyclicBarrier;
import java.util.stream.Stream;
import jdk.test.lib.thread.VThreadRunner;
public class VirtualThreadDeadlocks {
private static final Object LOCK1 = new Object();
private static final Object LOCK2 = new Object();
private static final CyclicBarrier barrier = new CyclicBarrier(2);
/**
* PP = test deadlock with two platform threads
* PV = test deadlock with one platform thread and one virtual thread
* VV = test deadlock with two virtual threads
*/
public static void main(String[] args) throws Exception {
// need at least two carrier threads due to pinning
VThreadRunner.ensureParallelism(2);
// start thread1
Thread.Builder builder1 = (args[0].charAt(0) == 'P')
? Thread.ofPlatform().daemon()
: Thread.ofVirtual();
Thread thread1 = builder1.start(() -> {
synchronized (LOCK1) {
try { barrier.await(); } catch (Exception ie) {}
synchronized (LOCK2) { }
}
});
System.out.println("thread1 => " + thread1);
// start thread2
Thread.Builder builder2 = (args[0].charAt(1) == 'P')
? Thread.ofPlatform().daemon()
: Thread.ofVirtual();
Thread thread2 = builder2.start(() -> {
synchronized (LOCK2) {
try { barrier.await(); } catch (Exception ie) {}
synchronized (LOCK1) { }
}
});
System.out.println("thread2 => " + thread2);
System.out.println("Waiting for thread1 and thread2 to deadlock ...");
awaitBlocked(thread1);
awaitBlocked(thread2);
ThreadMXBean bean = ManagementFactory.getPlatformMXBean(ThreadMXBean.class);
long[] deadlockedThreads = sorted(bean.findMonitorDeadlockedThreads());
System.out.println("findMonitorDeadlockedThreads => " + Arrays.toString(deadlockedThreads));
// deadlocks involving virtual threads are not detected
long[] expectedThreads = (!thread1.isVirtual() && !thread2.isVirtual())
? sorted(thread1.threadId(), thread2.threadId())
: null;
System.out.println("expected => " + Arrays.toString(expectedThreads));
if (!Arrays.equals(deadlockedThreads, expectedThreads))
throw new RuntimeException("Unexpected result");
}
private static void awaitBlocked(Thread thread) throws InterruptedException {
while (thread.getState() != Thread.State.BLOCKED) {
Thread.sleep(10);
if (!thread.isAlive()) {
throw new RuntimeException("Thread " + thread + " is terminated.");
}
}
}
private static long[] sorted(long... array) {
if (array != null) Arrays.sort(array);
return array;
}
}
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