1 /*
2 * Copyright (c) 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 ReservedStackTest
26 * @run main/othervm -XX:-Inline -XX:CompileCommand=exclude,java/util/concurrent/locks/AbstractOwnableSynchronizer,setExclusiveOwnerThread ReservedStackTest
27 */
28
29 /* The exclusion of java.util.concurrent.locks.AbstractOwnableSynchronizer.setExclusiveOwnerThread()
30 * from the compilable methods is required to ensure that the test will be able
31 * to trigger a StackOverflowError on the right method.
32 */
33
34
35 /*
36 * Notes about this test:
37 * This test tries to reproduce a rare but nasty corruption bug that
38 * occurs when a StackOverflowError is thrown in some critical sections
39 * of the ReentrantLock implementation.
40 *
41 * Here's the critical section where a corruption could occur
42 * (from java.util.concurrent.ReentrantLock.java)
43 *
44 * final void lock() {
45 * if (compareAndSetState(0, 1))
46 * setExclusiveOwnerThread(Thread.currentThread());
47 * else
48 * acquire(1);
49 * }
50 *
51 * The corruption occurs when the compareAndSetState(0, 1)
52 * successfully update the status of the lock but he method
53 * fails to set the owner because of a stack overflow.
54 * HotSpot checks for stack overflow on method invocations.
55 * The test must trigger a stack overflow either when
56 * Thread.currentThread() or setExclusiveOwnerThread() is
57 * invoked.
58 *
59 * The test starts with a recursive invocation loop until a
60 * first StackOverflowError is thrown, the Error is catched
61 * and a few dozens frames are exited. Now the thread has
62 * little free space on its execution stack and will try
63 * to trigger a stack overflow in the critical section.
64 * The test has a huge array of ReentrantLocks instances.
65 * The thread invokes a recursive method which, at each
66 * of its invocation, tries to acquire the next lock
67 * in the array. The execution continues until a
68 * StackOverflowError is thrown or the end of the array
69 * is reached.
70 * If no StackOverflowError has been thrown, the test
71 * is non conclusive (recommendation: increase the size
72 * of the ReentrantLock array).
73 * The status of all Reentrant locks in the array is checked,
74 * if a corruption is detected, the test failed, otherwise
75 * the test passed.
76 *
77 * To have a chance that the stack overflow occurs on one
78 * of the two targeted method invocations, the test is
79 * repeated in different threads. Each Java thread has a
80 * random size area allocated at the beginning of its
81 * stack to prevent false sharing. The test is using this
82 * to have different stack alignments and hit the targeted
83 * methods (the test could have been writtent with a native
84 * method with alloca, but using different Java threads makes
85 * the test 100% Java).
86 *
87 * One additional trick is required to ensure that the stack
88 * overflow will occur on the Thread.currentThread() getter
89 * or the setExclusiveOwnerThread() setter.
90 *
91 * Potential stack overflows are detected by stack banging,
92 * at method invocation time.
93 * In interpreted code, the stack banging performed for the
94 * lock() method goes further than the stack banging performed
95 * for the getter or the setter method, so the potential stack
96 * overflow is detected before entering the critical section.
97 * In compiled code, the getter and the setter are in-lined,
98 * so the stack banging is only performed before entering the
99 * critical section.
100 * In order to have a stack banging that goes further for the
101 * getter/setter methods than for the lock() method, the test
102 * exploit the property that interpreter frames are (much)
103 * bigger than compiled code frames. When the test is run,
104 * a compiler option disables the compilation of the
105 * setExclusiveOwnerThread() method.
106 *
107 */
108
109 import java.util.concurrent.locks.ReentrantLock;
110
111 public class ReservedStackTest {
112
113 private static boolean isWindows() {
114 return System.getProperty("os.name").toLowerCase().startsWith("win");
115 }
116
117 static class ReentrantLockTest {
118
119 private ReentrantLock lockArray[];
120 // Frame sizes vary a lot between interpreted code and compiled code
121 // so the lock array has to be big enough to cover all cases.
122 // If test fails with message "Not conclusive test", try to increase
123 //LOCK_ARRAY_SIZE value
124 private static final int LOCK_ARRAY_SIZE = 8192;
125 private boolean stackOverflowErrorReceived;
126 StackOverflowError soe = null;
127 private int index = -1;
128
129 public void initialize() {
130 lockArray = new ReentrantLock[LOCK_ARRAY_SIZE];
131 for (int i = 0; i < LOCK_ARRAY_SIZE; i++) {
132 lockArray[i] = new ReentrantLock();
133 }
134 stackOverflowErrorReceived = false;
135 }
136
137 public String getResult() {
138 if (!stackOverflowErrorReceived) {
139 return "ERROR: Not conclusive test: no StackOverflowError received";
140 }
141 for (int i = 0; i < LOCK_ARRAY_SIZE; i++) {
142 if (lockArray[i].isLocked()) {
143 if (!lockArray[i].isHeldByCurrentThread()) {
144 StringBuilder s = new StringBuilder();
145 s.append("FAILED: ReentrantLock ");
146 s.append(i);
147 s.append(" looks corrupted");
148 return s.toString();
149 }
150 }
151 }
152 return "PASSED";
153 }
154
155 public void run() {
156 try {
157 lockAndCall(0);
158 } catch (StackOverflowError e) {
159 soe = e;
160 stackOverflowErrorReceived = true;
161 }
162 }
163
164 private void lockAndCall(int i) {
165 index = i;
166 if (i < LOCK_ARRAY_SIZE) {
167 lockArray[i].lock();
168 lockAndCall(i + 1);
169 }
170 }
171 }
172
173 static class RunWithSOEContext implements Runnable {
174
175 int counter;
176 int deframe;
177 int decounter;
178 int setupSOEFrame;
179 int testStartFrame;
180 ReentrantLockTest test;
181
182 public RunWithSOEContext(ReentrantLockTest test, int deframe) {
183 this.test = test;
184 this.deframe = deframe;
185 }
186
187 @Override
188 @jdk.internal.vm.annotation.ReservedStackAccess
189 public void run() {
190 counter = 0;
191 decounter = deframe;
192 test.initialize();
193 recursiveCall();
194 System.out.println("Framework got StackOverflowError at frame = " + counter);
195 System.out.println("Test started execution at frame = " + (counter - deframe));
196 String result = test.getResult();
197 System.out.println(result);
198 // The feature is not fully implemented on Windows platforms,
199 // corruptions are still possible
200 if (!isWindows() && !result.contains("PASSED")) {
201 System.exit(-1);
202 }
203 }
204
205 void recursiveCall() {
206 // Unused local variables to increase the frame size
207 long l1, l2, l3, l4, l5, l6, l7, l8, l9, l10, l11, l12, l13, l14, l15, l16, l17, l18, l19;
208 long l20, l21, l22, l23, l24, l25, l26, l27, l28, l30, l31, l32, l33, l34, l35, l36, l37;
209 counter++;
210 try {
211 recursiveCall();
212 } catch (StackOverflowError e) {
213 }
214 decounter--;
215 if (decounter == 0) {
216 setupSOEFrame = counter;
217 testStartFrame = counter - deframe;
218 test.run();
219 }
220 }
221 }
222
223 public static void main(String[] args) {
224 for (int i = 0; i < 1000; i++) {
225 // Each iteration has to be executed by a new thread. The test
226 // relies on the random size area pushed by the VM at the beginning
227 // of the stack of each Java thread it creates.
228 Thread thread = new Thread(new RunWithSOEContext(new ReentrantLockTest(), 256));
229 thread.start();
230 try {
231 thread.join();
232 } catch (InterruptedException ex) { }
233 }
234 }
235 }