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
161
|
/*
* Copyright (c) 2007, 2018, 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.
*/
package nsk.share.locks;
import java.util.*;
import nsk.share.TestBug;
import nsk.share.Wicket;
/*
* Class used to create deadlocked threads. It is possible create 2 or more deadlocked thread, also
* is is possible to specify resource of which type should lock each deadlocked thread
*/
public class DeadlockMaker {
// create deadlock with 2 threads
// lockType1 and lockType2 - type of locking resources used for deadlock creation
public static DeadlockedThread[] createDeadlockedThreads(LockType lockType1, LockType lockType2) {
DeadlockedThread[] resultThreads = new DeadlockedThread[2];
Wicket step1 = new Wicket();
Wicket step2 = new Wicket();
Wicket readyWicket = new Wicket(2);
DeadlockLocker locker1 = createLocker(lockType1, step1, step2, readyWicket);
DeadlockLocker locker2 = createLocker(lockType2, step2, step1, readyWicket);
locker1.setInner(locker2);
locker2.setInner(locker1);
resultThreads[0] = new DeadlockedThread(locker1);
resultThreads[1] = new DeadlockedThread(locker2);
resultThreads[0].start();
resultThreads[1].start();
readyWicket.waitFor();
// additional check to be sure that all threads really blocked
waitForDeadlock(resultThreads);
return resultThreads;
}
// create deadlock with several threads
// locksTypes - type of locking resources used for deadlock creation
public static DeadlockedThread[] createDeadlockedThreads(List<LockType> locksTypes) {
if (locksTypes.size() < 2) {
throw new IllegalArgumentException("Need at least 2 threads for deadlock");
}
int threadsNumber = locksTypes.size();
DeadlockedThread[] resultThreads = new DeadlockedThread[threadsNumber];
Wicket readyWicket = new Wicket(threadsNumber);
DeadlockLocker deadlockLockers[] = new DeadlockLocker[threadsNumber];
Wicket stepWickets[] = new Wicket[threadsNumber];
for (int i = 0; i < threadsNumber; i++)
stepWickets[i] = new Wicket();
int index1 = 0;
int index2 = 1;
for (int i = 0; i < threadsNumber; i++) {
Wicket step1 = stepWickets[index1];
Wicket step2 = stepWickets[index2];
deadlockLockers[i] = createLocker(locksTypes.get(i), step1, step2, readyWicket);
if (i > 0)
deadlockLockers[i - 1].setInner(deadlockLockers[i]);
index1 = (index1 + 1) % threadsNumber;
index2 = (index2 + 1) % threadsNumber;
}
deadlockLockers[threadsNumber - 1].setInner(deadlockLockers[0]);
for (int i = 0; i < threadsNumber; i++) {
resultThreads[i] = new DeadlockedThread(deadlockLockers[i]);
resultThreads[i].start();
}
readyWicket.waitFor();
// additional check to be sure that all threads really blocked
waitForDeadlock(resultThreads);
return resultThreads;
}
/*
* Wait when thread state will change to be sure that deadlock is really created
*/
static private void waitForDeadlock(DeadlockedThread[] threads) {
Set<Thread.State> targetStates = new HashSet<Thread.State>();
// thread is waiting for a monitor lock to enter a synchronized block/method
targetStates.add(Thread.State.BLOCKED);
// thread calls LockSupport.park
targetStates.add(Thread.State.WAITING);
// thread calls LockSupport.parkNanos or LockSupport.parkUntil
targetStates.add(Thread.State.TIMED_WAITING);
for (Thread thread : threads) {
while (!targetStates.contains(thread.getState())) {
sleep(100);
}
}
}
static private void sleep(long millis) {
try {
Thread.sleep(millis);
} catch (InterruptedException e) {
System.out.println("Unexpected exception: " + e);
e.printStackTrace(System.out);
TestBug testBugException = new TestBug("Unexpected exception was throw: " + e);
testBugException.initCause(e);
throw testBugException;
}
}
// create locker with given type
public static DeadlockLocker createLocker(LockType type, Wicket step1, Wicket step2, Wicket readyWicket) {
switch (type) {
case SYNCHRONIZED_METHOD:
return new SynchronizedMethodLocker(step1, step2, readyWicket);
case SYNCHRONIZED_BLOCK:
return new SynchronizedBlockLocker(step1, step2, readyWicket);
case REENTRANT_LOCK:
return new ReentrantLockLocker(step1, step2, readyWicket);
case JNI_LOCK:
return new JNIMonitorLocker(step1, step2, readyWicket);
}
throw new IllegalArgumentException("Unsupported lock type: " + type);
}
}
|
