1 /*
2 * Copyright (c) 2021, 2024, 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 import jdk.test.lib.Asserts;
24 import jdk.test.lib.Utils;
25 import jdk.test.lib.process.ProcessTools;
26 import jdk.test.lib.process.OutputAnalyzer;
27
28 import java.lang.reflect.Constructor;
29 import java.lang.reflect.InvocationTargetException;
30 import java.util.List;
31 import java.util.concurrent.atomic.AtomicReference;
32 import java.util.concurrent.ExecutorService;
33 import java.util.concurrent.Executor;
34 import java.util.concurrent.Executors;
35 import java.util.concurrent.ThreadFactory;
36 import java.util.regex.Matcher;
37 import java.util.regex.Pattern;
38
39 /*
40 * Tests that JNI monitors work correctly with virtual threads,
41 * There are multiple test scenarios that we check using unified logging output
42 * (both positive and negative tests). Each test case is handled by its own @-test
43 * definition so that we can run each sub-test independently.
44 *
45 * The original bug was only discovered because the ForkJoinPool worker thread terminated
46 * and trigerred an assertion failure. So we use a custom scheduler to give us control.
47 */
48
49 /**
50 * @test id=normal
51 * @bug 8327743
52 * @summary Normal lock then unlock
53 * @library /test/lib
54 * @modules java.base/java.lang:+open
55 * @requires vm.continuations
56 * @run driver JNIMonitor Normal
57 */
58
59 /**
60 * @test id=multiNormal
61 * @bug 8327743
62 * @summary Normal lock then unlock by multiple threads
63 * @library /test/lib
64 * @modules java.base/java.lang:+open
65 * @requires vm.continuations
66 * @run driver JNIMonitor MultiNormal
67 */
68
69 /**
70 * @test id=missingUnlock
71 * @bug 8327743
72 * @summary Don't do the unlock and exit normally
73 * @library /test/lib
74 * @modules java.base/java.lang:+open
75 * @requires vm.continuations
76 * @run driver JNIMonitor MissingUnlock
77 */
78
79 /**
80 * @test id=multiMissingUnlock
81 * @bug 8327743
82 * @summary Don't do the unlock and exit normally, by multiple threads
83 * @library /test/lib
84 * @modules java.base/java.lang:+open
85 * @requires vm.continuations
86 * @run driver JNIMonitor MultiMissingUnlock
87 */
88
89 /**
90 * @test id=missingUnlockWithThrow
91 * @bug 8327743
92 * @summary Don't do the unlock and exit by throwing
93 * @library /test/lib
94 * @modules java.base/java.lang:+open
95 * @requires vm.continuations
96 * @run driver JNIMonitor MissingUnlockWithThrow
97 */
98
99 /**
100 * @test id=multiMissingUnlockWithThrow
101 * @bug 8327743
102 * @summary Don't do the unlock and exit by throwing, by multiple threads
103 * @library /test/lib
104 * @modules java.base/java.lang:+open
105 * @requires vm.continuations
106 * @run driver JNIMonitor MultiMissingUnlockWithThrow
107 */
108
109 public class JNIMonitor {
110
111 public static void main(String[] args) throws Exception {
112 String test = args[0];
113 String[] cmdArgs = new String[] {
114 "-Djava.library.path=" + Utils.TEST_NATIVE_PATH,
115 // Grant access to ThreadBuilders$VirtualThreadBuilder
116 "--add-opens=java.base/java.lang=ALL-UNNAMED",
117 // Enable the JNI warning
118 "-Xcheck:jni",
119 "-Xlog:jni=debug",
120 // Enable thread termination logging as a visual cross-check
121 "-Xlog:thread+os=info",
122 // We only count monitors in LM_LEGACY mode
123 "-XX:LockingMode=1",
124 // Disable compact headers since that switches locking mode to LM_LIGHTWEIGHT
125 "-XX:-UseCompactObjectHeaders",
126 "JNIMonitor$" + test,
127 };
128 OutputAnalyzer oa = ProcessTools.executeTestJava(cmdArgs);
129 oa.shouldHaveExitValue(0);
130 oa.stdoutShouldMatch(terminated);
131
132 switch(test) {
133 case "Normal":
134 case "MultiNormal":
135 oa.stdoutShouldNotMatch(stillLocked);
136 break;
137 case "MissingUnlock":
138 oa.stdoutShouldMatch(stillLocked);
139 break;
140 case "MultiMissingUnlock":
141 parseOutputForPattern(oa.stdoutAsLines(), stillLocked, MULTI_THREAD_COUNT);
142 break;
143 case "MissingUnlockWithThrow":
144 oa.stdoutShouldMatch(stillLocked);
145 oa.stderrShouldContain(throwMsg);
146 break;
147 case "MultiMissingUnlockWithThrow":
148 parseOutputForPattern(oa.stdoutAsLines(), stillLocked, MULTI_THREAD_COUNT);
149 parseOutputForPattern(oa.stderrAsLines(), throwMsg, MULTI_THREAD_COUNT);
150 break;
151
152 default: throw new Error("Unknown arg: " + args[0]);
153 }
154 oa.reportDiagnosticSummary();
155 }
156
157 // The number of threads for a multi tests. Arbitrarily chosen to be > 1 but small
158 // enough to not waste too much time.
159 static final int MULTI_THREAD_COUNT = 5;
160
161 // The logging message for leaving a monitor JNI locked has the form
162 // [0.187s][debug][jni] VirtualThread (tid: 28, carrier id: 29) exiting with Objects still locked by JNI MonitorEnter.
163 // but if the test is run with other logging options then whitespace may get introduced in the
164 // log decorator sections, so ignore those.
165 static final String stillLocked = "VirtualThread \\(tid:.*exiting with Objects still locked by JNI MonitorEnter";
166 // The carrier thread termination logging has the form:
167 // [1.394s][info][os,thread] JavaThread exiting (name: "pool-1-thread-1", tid: 3090592).
168 static final String terminated = "JavaThread exiting \\(name: \"pool-1-thread-1\"";
169
170 static final String throwMsg = "Terminating via exception as requested";
171
172 // Check the process logging output for the given pattern to see if the expected number of
173 // lines are found.
174 private static void parseOutputForPattern(List<String> lines, String pattern, int expected) {
175 Pattern p = Pattern.compile(pattern);
176 int found = 0;
177 for (String line : lines) {
178 Matcher m = p.matcher(line);
179 if (m.find()) {
180 found++;
181 }
182 }
183 if (found != expected) {
184 throw new RuntimeException("Checking for pattern \"" + pattern + "\": expected "
185 + expected + " but found " + found);
186 }
187 }
188
189
190 // straight-forward interface to JNI monitor functions
191 static native int monitorEnter(Object o);
192 static native int monitorExit(Object o);
193
194 // Isolate the native library loading to the actual test cases, not the class that
195 // jtreg Driver will load and execute.
196 static class TestBase {
197
198 static {
199 System.loadLibrary("JNIMonitor");
200 }
201
202 // This gives us a way to control the scheduler used for our virtual threads. The test
203 // only works as intended when the virtual threads run on the same carrier thread (as
204 // that carrier maintains ownership of the monitor if the virtual thread fails to unlock it).
205 // The original issue was also only discovered due to the carrier thread terminating
206 // unexpectedly, so we can force that condition too by shutting down our custom scheduler.
207 private static Thread.Builder.OfVirtual virtualThreadBuilder(Executor scheduler) {
208 Thread.Builder.OfVirtual builder = Thread.ofVirtual();
209 try {
210 Class<?> clazz = Class.forName("java.lang.ThreadBuilders$VirtualThreadBuilder");
211 Constructor<?> ctor = clazz.getDeclaredConstructor(Executor.class);
212 ctor.setAccessible(true);
213 return (Thread.Builder.OfVirtual) ctor.newInstance(scheduler);
214 } catch (InvocationTargetException e) {
215 Throwable cause = e.getCause();
216 if (cause instanceof RuntimeException re) {
217 throw re;
218 }
219 throw new RuntimeException(e);
220 } catch (Exception e) {
221 throw new RuntimeException(e);
222 }
223 }
224
225 static void runTest(int nThreads, boolean skipUnlock, boolean throwOnExit) throws Throwable {
226 final Object[] monitors = new Object[nThreads];
227 for (int i = 0; i < nThreads; i++) {
228 monitors[i] = new Object();
229 }
230 final AtomicReference<Throwable> exception = new AtomicReference();
231 // Ensure all our VT's operate of the same carrier, sequentially.
232 ExecutorService scheduler = Executors.newSingleThreadExecutor();
233 ThreadFactory factory = virtualThreadBuilder(scheduler).factory();
234 for (int i = 0 ; i < nThreads; i++) {
235 Object monitor = skipUnlock ? monitors[i] : monitors[0];
236 Thread th = factory.newThread(() -> {
237 try {
238 int res = monitorEnter(monitor);
239 Asserts.assertTrue(res == 0, "monitorEnter should return 0.");
240 Asserts.assertTrue(Thread.holdsLock(monitor), "monitor should be owned");
241 Thread.yield();
242 if (!skipUnlock) {
243 res = monitorExit(monitor);
244 Asserts.assertTrue(res == 0, "monitorExit should return 0.");
245 Asserts.assertFalse(Thread.holdsLock(monitor), "monitor should be unowned");
246 }
247 } catch (Throwable t) {
248 exception.set(t);
249 }
250 if (throwOnExit) {
251 throw new RuntimeException(throwMsg);
252 }
253 });
254 th.start();
255 th.join();
256 if (exception.get() != null) {
257 throw exception.get();
258 }
259 }
260 // Now force carrier thread to shutdown.
261 scheduler.shutdown();
262 }
263 }
264
265 // These are the actual test case classes that get exec'd.
266
267 static class Normal extends TestBase {
268 public static void main(String[] args) throws Throwable {
269 runTest(1, false, false);
270 }
271 }
272
273 static class MultiNormal extends TestBase {
274 public static void main(String[] args) throws Throwable {
275 runTest(MULTI_THREAD_COUNT, false, false);
276 }
277 }
278
279 static class MissingUnlock extends TestBase {
280 public static void main(String[] args) throws Throwable {
281 runTest(1, true, false);
282 }
283 }
284
285 static class MultiMissingUnlock extends TestBase {
286 public static void main(String[] args) throws Throwable {
287 runTest(MULTI_THREAD_COUNT, true, false);
288 }
289 }
290
291 static class MissingUnlockWithThrow extends TestBase {
292 public static void main(String[] args) throws Throwable {
293 runTest(1, true, true);
294 }
295 }
296
297 static class MultiMissingUnlockWithThrow extends TestBase {
298 public static void main(String[] args) throws Throwable {
299 runTest(MULTI_THREAD_COUNT, true, true);
300 }
301 }
302
303 }