russell@unturf.com
0a580b313d
Authors: russell@unturf.com · brackishbert@gmail.com · foxhop.net · TimeHexOn.com Patches, unit tests, benchmarks, whitepaper, and outreach briefs. Public domain — no copyright claimed. Use freely.
124 lines
4.6 KiB
Java
124 lines
4.6 KiB
Java
/*
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* Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/**
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* @test
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* @bug 8352088
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* @summary If ThreadGroupReference.groups() is called very early on from an
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* event handler, it can cause a deadlock because the call can result
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* in ClassPrepareEvents, which the debug agent will block on until
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* the debugger handles them, which it won't because the event handler
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* thread is waiting for a reply to ThreadGroupReference.groups().
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*
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* @run build TestScaffold VMConnection TargetListener TargetAdapter
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* @run compile -g EarlyThreadGroupChildrenTest.java
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* @run main/othervm/timeout=20 EarlyThreadGroupChildrenTest
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*/
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import com.sun.jdi.*;
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import com.sun.jdi.event.*;
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import com.sun.jdi.request.*;
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import java.util.*;
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class EarlyThreadGroupChildrenTestTarg {
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public static void main(String[] args) throws InterruptedException {
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System.out.println("Start");
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System.out.println("Finish");
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}
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}
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/********** test program **********/
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public class EarlyThreadGroupChildrenTest extends TestScaffold {
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EarlyThreadGroupChildrenTest(String args[]) {
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super(args);
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}
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public static void main(String[] args) throws Exception {
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new EarlyThreadGroupChildrenTest(args).startTests();
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}
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/********** event handlers **********/
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ClassPrepareRequest cpRequest;
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ThreadStartRequest tsRequest;
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@Override
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public void threadStarted(ThreadStartEvent event) {
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System.out.println("Got ThreadStartEvent: " + event);
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cpRequest = eventRequestManager().createClassPrepareRequest();
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cpRequest.setSuspendPolicy(EventRequest.SUSPEND_ALL);
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cpRequest.enable();
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}
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static volatile int classPreparedCount = 0;
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@Override
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public void classPrepared(ClassPrepareEvent event) {
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try {
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++classPreparedCount;
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System.out.println("ClassPreparedEvent " + classPreparedCount +
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" on thread " + event.thread() +
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": " + event.referenceType());
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List<ThreadGroupReference> groups = vm().topLevelThreadGroups();
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ThreadGroupReference systemThreadGroup = groups.get(0);
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groups = systemThreadGroup.threadGroups();
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System.out.println("system child ThreadGroups: " + groups);
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} catch (VMDisconnectedException e) {
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// This usually eventually happens during shutdown.
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System.out.println("ClassPreparedEvent " + classPreparedCount +
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": Got VMDisconnectedException");
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}
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}
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public void vmDisconnected(VMDisconnectEvent event) {
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System.out.println("Got VMDisconnectEvent");
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}
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/********** test core **********/
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protected void runTests() throws Exception {
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connect(new String[]{"EarlyThreadGroupChildrenTestTarg"});
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System.out.println("Connected: ");
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waitForVMStart();
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System.out.println("VM Started: ");
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// Do not add until after the VMStartEvent has arrived. Otherwise the debuggee
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// will be resumed after handling the VMStartEvent, and we don't want it resumed.
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addListener(this);
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// Create a ThreadStartRequest for the first ThreadStartEvent. When this event is
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// received, we will enable ClassPrepareEvents.
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tsRequest = eventRequestManager().createThreadStartRequest();
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tsRequest.setSuspendPolicy(EventRequest.SUSPEND_ALL);
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tsRequest.addCountFilter(1);
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tsRequest.enable();
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resumeToVMDisconnect();
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// Failure mode for this test is deadlocking, so there is no error to check for.
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System.out.println("EarlyThreadGroupChildrenTest: passed");
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}
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}
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