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
|
/*
* Copyright (c) 2003, 2017, 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
* @bug 4757273
* @summary Test deadlock in MBeanServerDelegate listeners
* @author Eamonn McManus
*
* @run clean NotifDeadlockTest
* @run build NotifDeadlockTest
* @run main NotifDeadlockTest
*/
/*
* Test deadlock when a listener for an MBeanServerDelegate does a
* register or unregister of an MBean. Since such a listener is
* triggered by a register or unregister operation, deadlock scenarios
* are possible if there are any locks held while the listener is
* being dispatched.
*
* The flow of control looks rather like this:
*
* Thread 1:
* - MBeanServer.createMBean(..., objectName1);
* --- MBeanServerDelegate.sendNotification
* ----- XListener.handleNotification
* ------- create Thread 2
* ------- wait for Thread 2 to complete
*
* Thread 2:
* - MBeanServer.createMBean(..., objectName2);
* - end Thread 2
*
* If any locks are held by Thread 1 within createMBean or
* sendNotification, then Thread 2 can block waiting for them.
* Since Thread 1 is itself waiting for Thread 2, this is a deadlock.
*
* We test all four combinations of:
* (Thread1-create,Thread1-unregister) x (Thread2-create,Thread2-unregister)
*
* In the JMX 1.1 RI, all four tests fail. In the JMX 1.2 RI, all four
* tests should pass.
*/
import javax.management.*;
public class NotifDeadlockTest {
static ObjectName on1, on2, delName;
static {
try {
on1 = new ObjectName("thing:a=b");
on2 = new ObjectName("thing:c=d");
delName =
new ObjectName("JMImplementation:type=MBeanServerDelegate");
} catch (MalformedObjectNameException e) {
throw new Error();
}
}
static MBeanServer mbs;
/* This listener registers or unregisters the MBean called on2
when triggered. */
private static class XListener implements NotificationListener {
private boolean firstTime = true;
private final boolean register;
XListener(boolean register) {
this.register = register;
}
public void handleNotification(Notification not, Object handback) {
if (firstTime) {
firstTime = false;
Thread t = new Thread() {
public void run() {
try {
if (register) {
mbs.createMBean("javax.management.timer.Timer",
on2);
System.out.println("Listener created " + on2);
} else {
mbs.unregisterMBean(on2);
System.out.println("Listener removed " + on2);
}
} catch (Exception e) {
e.printStackTrace();
}
}
};
t.start();
try {
t.join();
} catch (InterruptedException e) {
e.printStackTrace(); // should not happen
}
}
}
}
public static void main(String[] args) throws Exception {
System.out.println("Test 1: in register notif, unregister an MBean");
mbs = MBeanServerFactory.createMBeanServer();
mbs.createMBean("javax.management.timer.Timer", on2);
mbs.addNotificationListener(delName, new XListener(false), null, null);
mbs.createMBean("javax.management.timer.Timer", on1);
MBeanServerFactory.releaseMBeanServer(mbs);
System.out.println("Test 1 completed");
System.out.println("Test 2: in unregister notif, unregister an MBean");
mbs = MBeanServerFactory.createMBeanServer();
mbs.createMBean("javax.management.timer.Timer", on1);
mbs.createMBean("javax.management.timer.Timer", on2);
mbs.addNotificationListener(delName, new XListener(false), null, null);
mbs.unregisterMBean(on1);
MBeanServerFactory.releaseMBeanServer(mbs);
System.out.println("Test 2 completed");
System.out.println("Test 3: in register notif, register an MBean");
mbs = MBeanServerFactory.createMBeanServer();
mbs.addNotificationListener(delName, new XListener(true), null, null);
mbs.createMBean("javax.management.timer.Timer", on1);
MBeanServerFactory.releaseMBeanServer(mbs);
System.out.println("Test 3 completed");
System.out.println("Test 4: in unregister notif, register an MBean");
mbs = MBeanServerFactory.createMBeanServer();
mbs.createMBean("javax.management.timer.Timer", on1);
mbs.addNotificationListener(delName, new XListener(true), null, null);
mbs.unregisterMBean(on1);
MBeanServerFactory.releaseMBeanServer(mbs);
System.out.println("Test 4 completed");
System.out.println("Test passed");
}
}
|
