1 /*
  2  * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4  *
  5  * This code is free software; you can redistribute it and/or modify it
  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.
  8  *
  9  * This code is distributed in the hope that it will be useful, but WITHOUT
 10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 12  * version 2 for more details (a copy is included in the LICENSE file that
 13  * accompanied this code).
 14  *
 15  * You should have received a copy of the GNU General Public License version
 16  * 2 along with this work; if not, write to the Free Software Foundation,
 17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 18  *
 19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 20  * or visit www.oracle.com if you need additional information or have any
 21  * questions.
 22  */
 23 
 24 /**
 25  * @test
 26  * @bug 8312174
 27  * @summary missing JVMTI events from vthreads parked during JVMTI attach
 28  * @requires vm.continuations
 29  * @requires vm.jvmti
 30  * @requires vm.compMode != "Xcomp"


 31  * @run main/othervm/native
 32  *     -Djdk.virtualThreadScheduler.parallelism=9
 33  *     -Djdk.attach.allowAttachSelf=true -XX:+EnableDynamicAgentLoading VThreadEventTest attach
 34  */
 35 
 36 import com.sun.tools.attach.VirtualMachine;
 37 import java.util.concurrent.ExecutorService;
 38 import java.util.concurrent.Executors;
 39 import java.util.concurrent.locks.LockSupport;
 40 import java.util.List;
 41 import java.util.ArrayList;
 42 
 43 /*
 44  * The test uses custom implementation of the CountDownLatch class.
 45  * The reason is we want the state of tested thread to be predictable.
 46  * With java.util.concurrent.CountDownLatch it is not clear what thread state is expected.
 47  */
 48 class CountDownLatch {
 49     private int count = 0;
 50 
 51     CountDownLatch(int count) {
 52         this.count = count;
 53     }
 54 
 55     public synchronized void countDown() {
 56         count--;
 57         notify();
 58     }
 59 
 60     public synchronized void await() throws InterruptedException {
 61         while (count > 0) {
 62             wait(1);
 63         }
 64     }
 65 }
 66 
 67 public class VThreadEventTest {
 68     static final int TCNT1 = 10;
 69     static final int TCNT2 = 4;
 70     static final int TCNT3 = 4;
 71     static final int THREAD_CNT = TCNT1 + TCNT2 + TCNT3;
 72 
 73     private static void log(String msg) { System.out.println(msg); }
 74 
 75     private static native int threadEndCount();
 76     private static native int threadMountCount();
 77     private static native int threadUnmountCount();
 78 
 79     private static volatile boolean attached;
 80     private static boolean failed;
 81     private static List<Thread> test1Threads = new ArrayList(TCNT1);
 82 
 83     private static CountDownLatch ready0 = new CountDownLatch(THREAD_CNT);
 84     private static CountDownLatch ready1 = new CountDownLatch(TCNT1);
 85     private static CountDownLatch ready2 = new CountDownLatch(THREAD_CNT);
 86     private static CountDownLatch mready = new CountDownLatch(1);
 87 
 88     private static void await(CountDownLatch dumpedLatch) {
 89         try {
 90             dumpedLatch.await();
 91         } catch (InterruptedException e) {
 92             throw new RuntimeException(e);
 93         }
 94     }
 95 
 96     // The test1 vthreads are kept unmounted until interrupted after agent attach.
 97     static final Runnable test1 = () -> {
 98         synchronized (test1Threads) {
 99             test1Threads.add(Thread.currentThread());
100         }
101         log("test1 vthread started");
102         ready0.countDown();
103         await(mready);
104         ready1.countDown(); // to guaranty state is not State.WAITING after await(mready)
105         try {
106             Thread.sleep(20000); // big timeout to keep unmounted until interrupted
107         } catch (InterruptedException ex) {
108             // it is expected, ignore





109         }
110         ready2.countDown();
111     };
112 
113     // The test2 vthreads are kept mounted until agent attach.
114     static final Runnable test2 = () -> {
115         log("test2 vthread started");
116         ready0.countDown();
117         await(mready);
118         while (!attached) {
119             // keep mounted







120         }
121         ready2.countDown();
122     };
123 
124     // The test3 vthreads are kept mounted until agent attach.
125     static final Runnable test3 = () -> {
126         log("test3 vthread started");
127         ready0.countDown();
128         await(mready);
129         while (!attached) {
130             // keep mounted
131         }
132         LockSupport.parkNanos(10_000_000L); // will cause extra mount and unmount
133         ready2.countDown();
134     };
135 
136     public static void main(String[] args) throws Exception {
137         if (Runtime.getRuntime().availableProcessors() < 8) {
138             log("WARNING: test expects at least 8 processors.");
139         }
140         try (ExecutorService executorService = Executors.newVirtualThreadPerTaskExecutor()) {
141             for (int i = 0; i < TCNT1; i++) {
142                 executorService.execute(test1);
143             }
144             for (int i = 0; i < TCNT2; i++) {
145                 executorService.execute(test2);
146             }
147             for (int i = 0; i < TCNT3; i++) {
148                 executorService.execute(test3);
149             }
150             await(ready0);
151             mready.countDown();
152             await(ready1); // to guarantee state is not State.TIMED_WAITING after await(mready) in test1()
153             // wait for test1 threads to reach TIMED_WAITING state in sleep()
154             for (Thread t : test1Threads) {
155                 Thread.State state = t.getState();
156                 log("DBG: state: " + state);
157                 while (state != Thread.State.TIMED_WAITING) {
158                     Thread.sleep(10);
159                     state = t.getState();
160                     log("DBG: state: " + state);
161                 }
162             }
163 
164             VirtualMachine vm = VirtualMachine.attach(String.valueOf(ProcessHandle.current().pid()));
165             vm.loadAgentLibrary("VThreadEventTest");
166             Thread.sleep(200); // to allow the agent to get ready
167 
168             attached = true;
169             for (Thread t : test1Threads) {
170                  t.interrupt();
171             }
172             ready2.await();
173         }
174         // wait until all VirtualThreadEnd events have been sent
175         for (int sleepNo = 1; threadEndCount() < THREAD_CNT; sleepNo++) {
176             Thread.sleep(100);
177             if (sleepNo % 100 == 0) { // 10 sec period of waiting
178                 log("main: waited seconds: " + sleepNo/10);
179             }
180         }

181         int threadEndCnt = threadEndCount();
182         int threadMountCnt = threadMountCount();
183         int threadUnmountCnt = threadUnmountCount();
184         int threadEndExp = THREAD_CNT;
185         int threadMountExp = THREAD_CNT - TCNT2;
186         int threadUnmountExp = THREAD_CNT + TCNT3;
187 
188         log("ThreadEnd cnt: "     + threadEndCnt     + " (expected: " + threadEndExp + ")");
189         log("ThreadMount cnt: "   + threadMountCnt   + " (expected: " + threadMountExp + ")");
190         log("ThreadUnmount cnt: " + threadUnmountCnt + " (expected: " + threadUnmountExp + ")");

191 
192         if (threadEndCnt != threadEndExp) {
193             log("FAILED: unexpected count of ThreadEnd events");


194             failed = true;
195         }
196         if (threadMountCnt != threadMountExp) {
197             log("FAILED: unexpected count of ThreadMount events");
198             failed = true;
199         }
200         if (threadUnmountCnt != threadUnmountExp) {
201             log("FAILED: unexpected count of ThreadUnmount events");
202             failed = true;
203         }
204         if (failed) {
205             throw new RuntimeException("FAILED: event count is wrong");
206         }
207     }
208 









209 }
210 
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