1 /*
2 * Copyright (c) 2005, 2015, 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 6318664
27 * @summary Test deadlock in MBeanRegistration.preDeregister method
28 * @author Eamonn McManus
29 * @modules java.management
30 * @run clean PreDeregisterDeadlockTest
31 * @run build PreDeregisterDeadlockTest
32 * @run main PreDeregisterDeadlockTest
33 */
34
35 import java.util.concurrent.*;
36 import javax.management.*;
37
38 public class PreDeregisterDeadlockTest {
39 public static interface BlibbyMBean {}
40
41 public static class Blibby implements BlibbyMBean, MBeanRegistration {
42 public Blibby(MBeanServer mbs, ObjectName otherName) {
43 this.mbs = mbs;
44 this.otherName = otherName;
45 }
46
47 public ObjectName preRegister(MBeanServer mbs, ObjectName on) {
48 return on;
49 }
50
51 public void postRegister(Boolean done) {}
52
53 public void preDeregister() {
54 if (otherName == null)
55 return;
56 try {
57 Thread t = new Thread() {
58 public void run() {
59 try {
60 mbs.unregisterMBean(otherName);
61 } catch (Throwable e) {
62 e.printStackTrace(System.out);
63 fail(e.toString());
64 }
65 }
66 };
67 t.start();
68 t.join(5000L);
69 if (t.isAlive())
70 fail("Deadlock detected");
71 } catch (Throwable e) {
72 e.printStackTrace(System.out);
73 fail(e.toString());
74 }
75 }
76
77 public void postDeregister() {}
78
79 private final MBeanServer mbs;
80 private final ObjectName otherName;
81 }
82
83 public static interface BlobbyMBean {}
84
85 public static class Blobby implements BlobbyMBean, MBeanRegistration {
86 public Blobby(MBeanServer mbs, Semaphore semaphore) {
87 this.mbs = mbs;
88 this.semaphore = semaphore;
89 }
90
91 public ObjectName preRegister(MBeanServer mbs, ObjectName on) {
92 this.objectName = on;
93 return on;
94 }
95
96 public void postRegister(Boolean done) {}
97
98 public void preDeregister() throws Exception {
99 Thread t = new Thread() {
100 public void run() {
101 try {
102 mbs.unregisterMBean(objectName);
103 fail("Nested unregister succeeded");
104 } catch (InstanceNotFoundException e) {
105 semaphore.release();
106 } catch (Throwable e) {
107 e.printStackTrace(System.out);
108 fail(e.toString());
109 }
110 }
111 };
112 t.start();
113 // Give the thread a chance to block so we are really
114 // testing parallelism. (On slow machines we might not
115 // really be testing it but we should be covered by our
116 // faster machines.)
117 Thread.sleep(500L);
118 }
119
120 public void postDeregister() {}
121
122 private final MBeanServer mbs;
123 private ObjectName objectName;
124 private final Semaphore semaphore;
125 }
126
127 public static void main(String[] args) throws Exception {
128 MBeanServer mbs = MBeanServerFactory.newMBeanServer();
129 ObjectName on1 = new ObjectName("a:type=Blibby,name=\"1\"");
130 ObjectName on2 = new ObjectName("a:type=Blibby,name=\"2\"");
131
132 // Test 1: preDeregister starts a thread which unregisters a
133 // different MBean: this must not deadlock
134 mbs.registerMBean(new Blibby(mbs, on2), on1);
135 mbs.registerMBean(new Blibby(mbs, null), on2);
136 mbs.unregisterMBean(on1);
137
138 // Test 2: preDeregister starts a thread which tries to
139 // unregister the same MBean: this thread should block until
140 // the original thread succeeds in unregistering, then
141 // get an InstanceNotFoundException. We wait for it to
142 // complete here, using the semaphore.
143 Semaphore semaphore = new Semaphore(0);
144 mbs.registerMBean(new Blobby(mbs, semaphore), on1);
145 mbs.unregisterMBean(on1);
146 boolean ok = semaphore.tryAcquire(1, 5, TimeUnit.SECONDS);
147 if (!ok)
148 fail("Second unregister thread did not complete");
149
150 if (failure == null)
151 System.out.println("OK: Test passed");
152 else
153 throw new Exception("TEST FAILED: " + failure);
154 }
155
156 private static void fail(String why) {
157 System.out.println("FAILED: " + why);
158 failure = why;
159 }
160
161 private static volatile String failure;
162 }