1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
|
/*
* Copyright (c) 2020, 2024, 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
* @summary Test stack traces in exceptions, stack frames walked by the StackWalker,
* and the stack trace returned by Thread.getStackTrace
* @requires vm.continuations
* @modules java.base/java.lang:+open java.management
* @library /test/lib
* @run junit StackFrames
* @run junit/othervm -XX:+UnlockDiagnosticVMOptions -XX:+ShowCarrierFrames StackFrames
*/
import java.lang.management.ManagementFactory;
import java.util.Arrays;
import java.util.Set;
import java.util.concurrent.Executor;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinWorkerThread;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicReference;
import java.util.stream.Stream;
import static java.lang.StackWalker.Option.*;
import jdk.test.lib.thread.VThreadRunner;
import jdk.test.lib.thread.VThreadScheduler;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
class StackFrames {
/**
* Test that the stack trace in exceptions does not include the carrier thread
* frames, except when running with -XX:+ShowCarrierFrames.
*/
@Test
void testStackTraceException() throws Exception {
VThreadRunner.run(() -> {
Exception e = new Exception();
boolean found = Arrays.stream(e.getStackTrace())
.map(StackTraceElement::getClassName)
.anyMatch("java.util.concurrent.ForkJoinPool"::equals);
assertTrue(found == hasJvmArgument("-XX:+ShowCarrierFrames"));
});
}
/**
* Test that StackWalker does not include carrier thread frames in the stream of
* stack frames.
*/
@Test
void testStackWalker() throws Exception {
VThreadRunner.run(() -> {
StackWalker walker = StackWalker.getInstance(Set.of(RETAIN_CLASS_REFERENCE));
boolean found = walker.walk(sf ->
sf.map(StackWalker.StackFrame::getDeclaringClass)
.anyMatch(c -> c == ForkJoinPool.class));
assertFalse(found);
});
}
/**
* Test Thread.getStackTrace returns the expected bottom frame for both the carrier
* and virtual thread.
*/
@Test
void testBottomFrames() throws Exception {
try (ForkJoinPool pool = new ForkJoinPool(1)) {
var carrierRef = new AtomicReference<Thread>();
Executor scheduler = task -> {
pool.submit(() -> {
carrierRef.set(Thread.currentThread());
task.run();
});
};
ThreadFactory factory = VThreadScheduler.virtualThreadFactory(scheduler);
var ready = new AtomicBoolean();
var done = new AtomicBoolean();
// create virtual thread to use custom scheduler
var vthread = factory.newThread(() -> {
ready.set(true);
while (!done.get()) {
Thread.onSpinWait();
}
});
vthread.start();
try {
awaitTrue(ready);
// get carrier Thread
Thread carrier = carrierRef.get();
assertTrue(carrier instanceof ForkJoinWorkerThread);
// bottom-most frame of virtual thread should be VirtualThread.run
System.err.println(vthread);
StackTraceElement[] vthreadStack = vthread.getStackTrace();
Stream.of(vthreadStack).forEach(e -> System.err.println(" " + e));
StackTraceElement bottomFrame = vthreadStack[vthreadStack.length - 1];
assertEquals("java.lang.VirtualThread.run",
bottomFrame.getClassName() + "." + bottomFrame.getMethodName());
// bottom-most frame of carrier thread should be Thread.run
System.err.println(carrier);
StackTraceElement[] carrierStack = carrier.getStackTrace();
Stream.of(carrierStack).forEach(e -> System.err.println(" " + e));
bottomFrame = carrierStack[carrierStack.length - 1];
assertEquals("java.util.concurrent.ForkJoinWorkerThread.run",
bottomFrame.getClassName() + "." + bottomFrame.getMethodName());
} finally {
done.set(true);
vthread.join();
}
}
}
/**
* Returns true if started with the given VM option.
*/
private static boolean hasJvmArgument(String arg) {
for (String argument : ManagementFactory.getRuntimeMXBean().getInputArguments()) {
if (argument.equals(arg)) return true;
}
return false;
}
/**
* Waits for the boolean value to become true.
*/
private static void awaitTrue(AtomicBoolean ref) throws InterruptedException {
while (!ref.get()) {
Thread.sleep(20);
}
}
}
|
