Java example source code file (TestLogConfigurationDeadLock.java)
The TestLogConfigurationDeadLock.java Java example source code/*
* Copyright (c) 2013, 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.
*/
import java.lang.management.ManagementFactory;
import java.lang.management.ThreadInfo;
import java.security.Permission;
import java.security.Policy;
import java.security.ProtectionDomain;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicLong;
import java.util.logging.LogManager;
import java.util.logging.Logger;
/**
* @test
* @bug 8029281 8027670
* @summary Synchronization issues in Logger and LogManager. This test
* focusses more particularly on potential deadlock in
* drainLoggerRefQueueBounded / readConfiguration
* @run main/othervm TestLogConfigurationDeadLock
* @author danielfuchs
*/
// This test is a best effort to try & detect issues. The test itself will run
// for 8secs. This is usually unsufficient to detect issues.
// To get a greater confidence it is recommended to run this test in a loop:
// e.g. use something like:
// $ while jtreg -jdk:$JDK -verbose:all \
// test/java/util/logging/TestLogConfigurationDeadLock.java ; \
// do echo Running test again ; done
// and let it run for a few hours...
//
public class TestLogConfigurationDeadLock {
static volatile Exception thrown = null;
static volatile boolean goOn = true;
static final int READERS = 2;
static final int LOGGERS = 2;
static final long TIME = 4 * 1000; // 4 sec.
static final long STEP = 1 * 1000; // message every 1 sec.
static final int LCOUNT = 50; // 50 loggers created in a row...
static final AtomicLong nextLogger = new AtomicLong(0);
static final AtomicLong readCount = new AtomicLong(0);
static final AtomicLong checkCount = new AtomicLong(0);
/**
* This test will run both with and without a security manager.
*
* The test starts a number of threads that will call
* LogManager.readConfiguration() concurrently (ReadConf), then starts
* a number of threads that will create new loggers concurrently
* (AddLogger), and then two additional threads: one (Stopper) that
* will stop the test after 4secs (TIME ms), and one DeadlockDetector
* that will attempt to detect deadlocks.
* If after 4secs no deadlock was detected and no exception was thrown
* then the test is considered a success and passes.
*
* This procedure is done twice: once without a security manager and once
* again with a security manager - which means the test takes ~8secs to
* run.
*
* Note that 8sec may not be enough to detect issues if there are some.
* This is a best effort test.
*
* @param args the command line arguments
*/
public static void main(String[] args) throws Exception {
// test without security
System.out.println("No security");
test();
// test with security
System.out.println("\nWith security");
Policy.setPolicy(new Policy() {
@Override
public boolean implies(ProtectionDomain domain, Permission permission) {
if (super.implies(domain, permission)) return true;
// System.out.println("Granting " + permission);
return true; // all permissions
}
});
System.setSecurityManager(new SecurityManager());
test();
}
/**
* Starts all threads, wait 4secs, then stops all threads.
* @throws Exception if a deadlock was detected or an error occurred.
*/
public static void test() throws Exception {
goOn = true;
thrown = null;
long sNextLogger = nextLogger.get();
long sReadCount = readCount.get();
long sCheckCount = checkCount.get();
List<Thread> threads = new ArrayList<>();
for (int i = 0; i<READERS; i++) {
threads.add(new ReadConf());
}
for (int i = 0; i<LOGGERS; i++) {
threads.add(new AddLogger());
}
threads.add(new DeadlockDetector());
threads.add(0, new Stopper(TIME));
for (Thread t : threads) {
t.start();
}
for (Thread t : threads) {
try {
t.join();
} catch (Exception x) {
fail(x);
}
}
if (thrown != null) {
throw thrown;
}
System.out.println("Passed: " + (nextLogger.get() - sNextLogger)
+ " loggers created by " + LOGGERS + " Thread(s),");
System.out.println("\t LogManager.readConfiguration() called "
+ (readCount.get() - sReadCount) + " times by " + READERS
+ " Thread(s).");
System.out.println("\t ThreadMXBean.findDeadlockedThreads called "
+ (checkCount.get() -sCheckCount) + " times by 1 Thread.");
}
final static class ReadConf extends Thread {
@Override
public void run() {
while (goOn) {
try {
LogManager.getLogManager().readConfiguration();
readCount.incrementAndGet();
Thread.sleep(1);
} catch (Exception x) {
fail(x);
}
}
}
}
final static class AddLogger extends Thread {
@Override
public void run() {
try {
while (goOn) {
Logger l;
Logger foo = Logger.getLogger("foo");
Logger bar = Logger.getLogger("foo.bar");
for (int i=0; i < LCOUNT ; i++) {
l = Logger.getLogger("foo.bar.l"+nextLogger.incrementAndGet());
l.fine("I'm fine");
if (!goOn) break;
Thread.sleep(1);
}
}
} catch (InterruptedException | RuntimeException x ) {
fail(x);
}
}
}
final static class DeadlockDetector extends Thread {
@Override
public void run() {
while(goOn) {
try {
long[] ids = ManagementFactory.getThreadMXBean().findDeadlockedThreads();
checkCount.incrementAndGet();
ids = ids == null ? new long[0] : ids;
if (ids.length == 1) {
throw new RuntimeException("Found 1 deadlocked thread: "+ids[0]);
} else if (ids.length > 0) {
ThreadInfo[] infos = ManagementFactory.getThreadMXBean().getThreadInfo(ids);
System.err.println("Found "+ids.length+" deadlocked threads: ");
for (ThreadInfo inf : infos) {
System.err.println(inf.toString());
}
throw new RuntimeException("Found "+ids.length+" deadlocked threads");
}
Thread.sleep(100);
} catch(InterruptedException | RuntimeException x) {
fail(x);
}
}
}
}
static final class Stopper extends Thread {
long start;
long time;
Stopper(long time) {
start = System.currentTimeMillis();
this.time = time;
}
@Override
public void run() {
try {
long rest, previous;
previous = time;
while (goOn && (rest = start - System.currentTimeMillis() + time) > 0) {
if (previous == time || previous - rest >= STEP) {
Logger.getLogger("remaining").info(String.valueOf(rest)+"ms remaining...");
previous = rest == time ? rest -1 : rest;
System.gc();
}
if (goOn == false) break;
Thread.sleep(Math.min(rest, 100));
}
System.out.println(System.currentTimeMillis() - start
+ " ms elapsed ("+time+ " requested)");
goOn = false;
} catch(InterruptedException | RuntimeException x) {
fail(x);
}
}
}
static void fail(Exception x) {
x.printStackTrace();
if (thrown == null) {
thrown = x;
}
goOn = false;
}
}
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