| /* |
| * Copyright (c) 2003, 2014, 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 |
| * @bug 4530538 |
| * @summary Basic unit test of ThreadInfo.getLockName() |
| * and ThreadInfo.getLockOwnerName() |
| * @author Mandy Chung |
| * @author Jaroslav Bachorik |
| * |
| * @library /lib/testlibrary |
| * @build jdk.testlibrary.* |
| * @run main/othervm Locks |
| */ |
| |
| import java.lang.management.*; |
| import java.util.concurrent.Phaser; |
| import jdk.testlibrary.LockFreeLogManager; |
| |
| public class Locks { |
| private static final Object objA = new Object(); |
| private static final Object objB = new Object(); |
| private static final Object objC = new Object(); |
| private static final ThreadMXBean tm = ManagementFactory.getThreadMXBean(); |
| private static final LockFreeLogManager logger = new LockFreeLogManager(); |
| |
| private static boolean testFailed = false; |
| |
| private static String getLockName(Object lock) { |
| if (lock == null) return null; |
| |
| return lock.getClass().getName() + '@' + |
| Integer.toHexString(System.identityHashCode(lock)); |
| } |
| |
| private static void assertNoLock(Thread t) { |
| long tid = t.getId(); |
| ThreadInfo info = tm.getThreadInfo(tid); |
| String result = info.getLockName(); |
| |
| if (result != null) { |
| throw new RuntimeException("Thread " + t.getName() + " is not supposed to hold any lock. " + |
| "Currently owning lock: " + result); |
| } |
| } |
| |
| private static void checkBlockedObject(Thread t, Object lock, Thread owner, |
| Thread.State expectedState) { |
| long tid = t.getId(); |
| ThreadInfo info = tm.getThreadInfo(tid); |
| String result = info.getLockName(); |
| String expectedLock = (lock != null ? getLockName(lock) : null); |
| String expectedOwner = (owner != null ? owner.getName() : null); |
| |
| if (lock != null) { |
| if (expectedState == Thread.State.BLOCKED) { |
| int retryCount=0; |
| while(info.getThreadState() != Thread.State.BLOCKED) { |
| if (retryCount++ > 500) { |
| throw new RuntimeException("Thread " + t.getName() + |
| " is expected to block on " + expectedLock + |
| " but got " + result + |
| " Thread.State = " + info.getThreadState()); |
| } |
| goSleep(100); |
| info = tm.getThreadInfo(tid); |
| result = info.getLockName(); |
| } |
| } |
| if (expectedState == Thread.State.WAITING && |
| info.getThreadState() != Thread.State.WAITING) { |
| throw new RuntimeException("Thread " + t.getName() + |
| " is expected to wait on " + expectedLock + |
| " but got " + result + |
| " Thread.State = " + info.getThreadState()); |
| } |
| } |
| |
| if ((result != null && !result.equals(expectedLock)) || |
| (result == null && expectedLock != null)) { |
| throw new RuntimeException("Thread " + t.getName() + " is blocked on " + |
| expectedLock + " but got " + result); |
| } |
| result = info.getLockOwnerName(); |
| if ((result != null && !result.equals(expectedOwner)) || |
| (result == null && expectedOwner != null)) { |
| throw new RuntimeException("Owner of " + lock + " should be " + |
| expectedOwner + " but got " + result); |
| } |
| } |
| |
| private static void goSleep(long ms) { |
| try { |
| Thread.sleep(ms); |
| } catch (InterruptedException e) { |
| e.printStackTrace(); |
| testFailed = true; |
| } |
| } |
| |
| private static volatile int dummyCounter = 0; |
| |
| static class LockAThread extends Thread { |
| private final Phaser p; |
| public LockAThread(Phaser p) { |
| super("LockAThread"); |
| this.p = p; |
| } |
| public void run() { |
| synchronized(objA) { |
| // stop here for LockBThread to hold objB |
| log("LockAThread about to block on objB"); |
| p.arriveAndAwaitAdvance(); // Phase 1 (blocking) |
| synchronized(objB) { |
| dummyCounter++; |
| }; |
| } |
| p.arriveAndAwaitAdvance(); // Phase 2 (blocking) |
| log("LockAThread about to exit"); |
| // Make sure the current thread is not holding any lock |
| assertNoLock(this); |
| } |
| } |
| |
| static class LockBThread extends Thread { |
| private final Phaser p; |
| public LockBThread(Phaser p) { |
| super("LockBThread"); |
| this.p = p; |
| } |
| public void run() { |
| synchronized(objB) { |
| log("LockBThread about to block on objC"); |
| p.arriveAndAwaitAdvance(); // Phase 1 (blocking) |
| // Signal main thread about to block on objC |
| synchronized(objC) { |
| dummyCounter++; |
| }; |
| } |
| p.arriveAndAwaitAdvance(); // Phase 2 (blocking) |
| log("LockBThread about to exit"); |
| // Make sure the current thread is not holding any lock |
| assertNoLock(this); |
| } |
| } |
| |
| private static WaitingThread waiter; |
| private static final Object ready = new Object(); |
| private static CheckerThread checker; |
| static class WaitingThread extends Thread { |
| private final Phaser p; |
| |
| volatile boolean waiting = false; |
| |
| public WaitingThread(Phaser p) { |
| super("WaitingThread"); |
| this.p = p; |
| } |
| @Override |
| public void run() { |
| synchronized(objC) { |
| log("WaitingThread about to wait on objC"); |
| try { |
| // Signal checker thread, about to wait on objC. |
| waiting = false; |
| p.arriveAndAwaitAdvance(); // Phase 1 (waiting) |
| waiting = true; |
| objC.wait(); |
| } catch (InterruptedException e) { |
| e.printStackTrace(); |
| testFailed = true; |
| } |
| |
| // block until CheckerThread finishes checking |
| log("WaitingThread about to block on ready"); |
| // signal checker thread that it is about acquire |
| // object ready. |
| p.arriveAndAwaitAdvance(); // Phase 2 (waiting) |
| synchronized(ready) { |
| dummyCounter++; |
| } |
| } |
| synchronized(objC) { |
| try { |
| // signal checker thread, about to wait on objC |
| waiting = false; |
| p.arriveAndAwaitAdvance(); // Phase 3 (waiting) |
| waiting = true; |
| objC.wait(); |
| } catch (InterruptedException e) { |
| e.printStackTrace(); |
| testFailed = true; |
| } |
| } |
| log("WaitingThread about to exit waiting on objC 2"); |
| } |
| |
| public void waitForWaiting() { |
| p.arriveAndAwaitAdvance(); |
| while (!waiting) { |
| goSleep(10); |
| } |
| waitForState(State.WAITING); |
| } |
| |
| public void waitForBlocked() { |
| p.arriveAndAwaitAdvance(); |
| waitForState(State.BLOCKED); |
| } |
| |
| private void waitForState(Thread.State state) { |
| while (!waiter.isInterrupted() && waiter.getState() != state) { |
| Thread.yield(); |
| } |
| } |
| } |
| static class CheckerThread extends Thread { |
| public CheckerThread() { |
| super("CheckerThread"); |
| } |
| |
| public void run() { |
| synchronized (ready) { |
| // wait until WaitingThread about to wait for objC |
| waiter.waitForWaiting(); // Phase 1 (waiting) |
| checkBlockedObject(waiter, objC, null, Thread.State.WAITING); |
| |
| synchronized (objC) { |
| objC.notify(); |
| } |
| |
| // wait for waiter thread to about to enter |
| // synchronized object ready. |
| waiter.waitForBlocked(); // Phase 2 (waiting) |
| checkBlockedObject(waiter, ready, this, Thread.State.BLOCKED); |
| } |
| |
| // wait for signal from waiting thread that it is about |
| // wait for objC. |
| waiter.waitForWaiting(); // Phase 3 (waiting) |
| synchronized(objC) { |
| checkBlockedObject(waiter, objC, Thread.currentThread(), Thread.State.WAITING); |
| objC.notify(); |
| } |
| |
| } |
| } |
| |
| public static void main(String args[]) throws Exception { |
| Thread mainThread = Thread.currentThread(); |
| |
| // Test uncontested case |
| LockAThread t1; |
| LockBThread t2; |
| |
| Phaser p = new Phaser(3); |
| synchronized(objC) { |
| // Make sure the main thread is not holding any lock |
| assertNoLock(mainThread); |
| |
| // Test deadlock case |
| // t1 holds lockA and attempts to lock B |
| // t2 holds lockB and attempts to lock C |
| |
| t1 = new LockAThread(p); |
| t1.start(); |
| |
| t2 = new LockBThread(p); |
| t2.start(); |
| |
| p.arriveAndAwaitAdvance(); // Phase 1 (blocking) |
| checkBlockedObject(t2, objC, mainThread, Thread.State.BLOCKED); |
| checkBlockedObject(t1, objB, t2, Thread.State.BLOCKED); |
| |
| long[] expectedThreads = new long[3]; |
| expectedThreads[0] = t1.getId(); // blocked on lockB |
| expectedThreads[1] = t2.getId(); // owner of lockB blocking on lockC |
| expectedThreads[2] = mainThread.getId(); // owner of lockC |
| findThreadsBlockedOn(objB, expectedThreads); |
| } |
| p.arriveAndAwaitAdvance(); // Phase 2 (blocking) |
| |
| p = new Phaser(2); |
| // Test Object.wait() case |
| waiter = new WaitingThread(p); |
| waiter.start(); |
| |
| checker = new CheckerThread(); |
| checker.start(); |
| |
| try { |
| waiter.join(); |
| checker.join(); |
| } catch (InterruptedException e) { |
| e.printStackTrace(); |
| testFailed = true; |
| } |
| |
| if (testFailed) { |
| throw new RuntimeException("TEST FAILED."); |
| } |
| System.out.println("Test passed."); |
| } |
| |
| private static ThreadInfo findOwnerInfo(ThreadInfo[] infos, String lock) |
| throws Exception { |
| ThreadInfo ownerInfo = null; |
| for (ThreadInfo info : infos) { |
| String blockedLock = info.getLockName(); |
| if (lock.equals(blockedLock)) { |
| long threadId = info.getLockOwnerId(); |
| if (threadId == -1) { |
| throw new RuntimeException("TEST FAILED: " + |
| lock + " expected to have owner"); |
| } |
| for (int j = 0; j < infos.length; j++) { |
| if (infos[j].getThreadId() == threadId) { |
| ownerInfo = infos[j]; |
| break; |
| } |
| } |
| } |
| } |
| return ownerInfo; |
| } |
| private static void findThreadsBlockedOn(Object o, long[] expectedThreads) |
| throws Exception { |
| String lock = getLockName(o); |
| // Check with ThreadInfo with no stack trace (i.e. no safepoint) |
| ThreadInfo[] infos = tm.getThreadInfo(tm.getAllThreadIds()); |
| doCheck(infos, lock, expectedThreads); |
| |
| // Check with ThreadInfo with stack trace |
| infos = tm.getThreadInfo(tm.getAllThreadIds(), 1); |
| doCheck(infos, lock, expectedThreads); |
| } |
| |
| private static void doCheck(ThreadInfo[] infos, String lock, long[] expectedThreads) |
| throws Exception { |
| ThreadInfo ownerInfo = null; |
| // Find the thread who is blocking on lock |
| for (ThreadInfo info : infos) { |
| String blockedLock = info.getLockName(); |
| if (lock.equals(blockedLock)) { |
| log("%s blocked on %s", info.getThreadName(), blockedLock); |
| ownerInfo = info; |
| } |
| } |
| if (ownerInfo == null) { |
| throw new RuntimeException("TEST FAILED: " + |
| "Can't retrieve ThreadInfo for the blocked thread"); |
| } |
| |
| long[] threads = new long[10]; |
| int count = 0; |
| threads[count++] = ownerInfo.getThreadId(); |
| while (ownerInfo != null && ownerInfo.getThreadState() == Thread.State.BLOCKED) { |
| ownerInfo = findOwnerInfo(infos, lock); |
| threads[count++] = ownerInfo.getThreadId(); |
| log(" Owner = %s id = %d", |
| ownerInfo.getThreadName(), |
| ownerInfo.getThreadId() |
| ); |
| lock = ownerInfo.getLockName(); |
| log("%s Id = %d blocked on %s", |
| ownerInfo.getThreadName(), |
| ownerInfo.getThreadId(), |
| lock |
| ); |
| } |
| log(""); |
| |
| if (count != expectedThreads.length) { |
| throw new RuntimeException("TEST FAILED: " + |
| "Expected chain of threads not matched; current count =" + count); |
| } |
| for (int i = 0; i < count; i++) { |
| if (threads[i] != expectedThreads[i]) { |
| log("TEST FAILED: Unexpected thread in the chain %s expected to be %s", |
| threads[i], |
| expectedThreads[i] |
| ); |
| } |
| } |
| } |
| |
| private static void log(String format, Object ... args) { |
| logger.log(format + "%n", args); |
| } |
| } |
