1 /*
2 * Copyright (c) 2015, 2018, 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 *
27 * @requires vm.opt.DeoptimizeALot == null | vm.opt.DeoptimizeALot == false
28 * @library /test/lib
29 * @modules java.base/jdk.internal.misc
30 * @modules java.base/jdk.internal.vm.annotation
31 *
32 * @run main/othervm -XX:MaxInlineLevel=2 -XX:CompileCommand=exclude,java/util/concurrent/locks/AbstractOwnableSynchronizer.setExclusiveOwnerThread ReservedStackTest
33 */
34
35 /* The exclusion of java.util.concurrent.locks.AbstractOwnableSynchronizer.setExclusiveOwnerThread()
36 * from the compilable methods is required to ensure that the test will be able
37 * to trigger a StackOverflowError on the right method.
38 */
39
40
41 /*
42 * Notes about this test:
43 * This test tries to reproduce a rare but nasty corruption bug that
44 * occurs when a StackOverflowError is thrown in some critical sections
45 * of the ReentrantLock implementation.
46 *
47 * Here's the critical section where a corruption could occur
48 * (from java.util.concurrent.ReentrantLock.java)
49 *
50 * final void lock() {
51 * if (compareAndSetState(0, 1))
52 * setExclusiveOwnerThread(Thread.currentThread());
53 * else
54 * acquire(1);
55 * }
56 *
57 * The corruption occurs when the compareAndSetState(0, 1)
58 * successfully updates the status of the lock but the method
59 * fails to set the owner because of a stack overflow.
60 * HotSpot checks for stack overflow on method invocations.
61 * The test must trigger a stack overflow either when
62 * Thread.currentThread() or setExclusiveOwnerThread() is
63 * invoked.
64 *
65 * The test starts with a recursive invocation loop until a
66 * first StackOverflowError is thrown, the Error is caught
67 * and a few dozen frames are exited. Now the thread has
68 * little free space on its execution stack and will try
69 * to trigger a stack overflow in the critical section.
70 * The test has a huge array of ReentrantLocks instances.
71 * The thread invokes a recursive method which, at each
72 * of its invocations, tries to acquire the next lock
73 * in the array. The execution continues until a
74 * StackOverflowError is thrown or the end of the array
75 * is reached.
76 * If no StackOverflowError has been thrown, the test
77 * is non conclusive (recommendation: increase the size
78 * of the ReentrantLock array).
79 * The status of all Reentrant locks in the array is checked,
80 * if a corruption is detected, the test failed, otherwise
81 * the test passed.
82 *
83 * To have a chance that the stack overflow occurs on one
84 * of the two targeted method invocations, the test is
85 * repeated in different threads. Each Java thread has a
86 * random size area allocated at the beginning of its
87 * stack to prevent false sharing. The test relies on this
88 * to have different stack alignments when it hits the targeted
89 * methods (the test could have been written with a native
90 * method with alloca, but using different Java threads makes
91 * the test 100% Java).
92 *
93 * One additional trick is required to ensure that the stack
94 * overflow will occur on the Thread.currentThread() getter
95 * or the setExclusiveOwnerThread() setter.
96 *
97 * Potential stack overflows are detected by stack banging,
98 * at method invocation time.
99 * In interpreted code, the stack banging performed for the
100 * lock() method goes further than the stack banging performed
101 * for the getter or the setter method, so the potential stack
102 * overflow is detected before entering the critical section.
103 * In compiled code, the getter and the setter are in-lined,
104 * so the stack banging is only performed before entering the
105 * critical section.
106 * In order to have a stack banging that goes further for the
107 * getter/setter methods than for the lock() method, the test
108 * exploits the property that interpreter frames are (much)
109 * bigger than compiled code frames. When the test is run,
110 * a compiler option disables the compilation of the
111 * setExclusiveOwnerThread() method.
112 *
113 */
114
115 import java.util.concurrent.locks.ReentrantLock;
116 import jdk.test.lib.Platform;
117 import jdk.test.lib.process.ProcessTools;
118 import jdk.test.lib.process.OutputAnalyzer;
119
120 public class ReservedStackTest {
121
122 static class ReentrantLockTest {
123
124 private ReentrantLock lockArray[];
125 // Frame sizes vary a lot between interpreted code and compiled code
126 // so the lock array has to be big enough to cover all cases.
127 // If test fails with message "Not conclusive test", try to increase
128 // LOCK_ARRAY_SIZE value
129 private static final int LOCK_ARRAY_SIZE = 8192;
130 private boolean stackOverflowErrorReceived;
131 StackOverflowError soe = null;
132 private int index = -1;
133
134 public void initialize() {
135 lockArray = new ReentrantLock[LOCK_ARRAY_SIZE];
136 for (int i = 0; i < LOCK_ARRAY_SIZE; i++) {
137 lockArray[i] = new ReentrantLock();
138 }
139 stackOverflowErrorReceived = false;
140 }
141
142 public String getResult() {
143 if (!stackOverflowErrorReceived) {
144 return "ERROR: Not conclusive test: no StackOverflowError received";
145 }
146 for (int i = 0; i < LOCK_ARRAY_SIZE; i++) {
147 if (lockArray[i].isLocked()) {
148 if (!lockArray[i].isHeldByCurrentThread()) {
149 StringBuilder s = new StringBuilder();
150 s.append("FAILED: ReentrantLock ");
151 s.append(i);
152 s.append(" looks corrupted");
153 return s.toString();
154 }
155 }
156 }
157 return "PASSED";
158 }
159
160 public void run() {
161 try {
162 lockAndCall(0);
163 } catch (StackOverflowError e) {
164 soe = e;
165 stackOverflowErrorReceived = true;
166 throw e;
167 }
168 }
169
170 private void lockAndCall(int i) {
171 index = i;
172 if (i < LOCK_ARRAY_SIZE) {
173 lockArray[i].lock();
174 lockAndCall(i + 1);
175 }
176 }
177 }
178
179 static class RunWithSOEContext implements Runnable {
180
181 int counter;
182 int deframe;
183 int decounter;
184 int setupSOEFrame;
185 int testStartFrame;
186 ReentrantLockTest test;
187
188 public RunWithSOEContext(ReentrantLockTest test, int deframe) {
189 this.test = test;
190 this.deframe = deframe;
191 }
192
193 @Override
194 @jdk.internal.vm.annotation.ReservedStackAccess
195 public void run() {
196 counter = 0;
197 decounter = deframe;
198 test.initialize();
199 recursiveCall();
200 String result = test.getResult();
201 // The feature is not fully implemented on all platforms,
202 // corruptions are still possible.
203 if (isSupportedPlatform && !result.contains("PASSED")) {
204 throw new Error(result);
205 } else {
206 // Either the test passed or this platform is not supported.
207 // On not supported platforms, we only expect the VM to
208 // not crash during the test. This is especially important
209 // on Windows where the detection of SOE in annotated
210 // sections is implemented but the reserved zone mechanism
211 // to avoid the corruption cannot be implemented yet
212 // because of JDK-8067946
213 System.out.println("PASSED");
214 }
215 }
216
217 void recursiveCall() {
218 // Unused local variables to increase the frame size
219 long l1, l2, l3, l4, l5, l6, l7, l8, l9, l10, l11, l12, l13, l14, l15, l16, l17, l18, l19;
220 long l20, l21, l22, l23, l24, l25, l26, l27, l28, l30, l31, l32, l33, l34, l35, l36, l37;
221 counter++;
222 try {
223 recursiveCall();
224 } catch (StackOverflowError e) {
225 }
226 decounter--;
227 if (decounter == 0) {
228 setupSOEFrame = counter;
229 testStartFrame = counter - deframe;
230 test.run();
231 }
232 }
233 }
234
235 private static boolean isAlwaysSupportedPlatform() {
236 // Note: To date Aarch64 is the only platform that we don't statically
237 // know if it supports the reserved stack area. This is because the
238 // open Aarch64 port supports it and the Oracle arm64 port does not.
239 return Platform.isAix() ||
240 (Platform.isLinux() &&
241 (Platform.isPPC() || Platform.isS390x() || Platform.isX64() ||
242 Platform.isX86())) ||
243 Platform.isOSX() ||
244 Platform.isSolaris();
245 }
246
247 private static boolean isNeverSupportedPlatform() {
248 return !isAlwaysSupportedPlatform() && !Platform.isAArch64();
249 }
250
251 private static boolean isSupportedPlatform;
252
253 private static void initIsSupportedPlatform() throws Exception {
254 // In order to dynamicaly determine if the platform supports the reserved
255 // stack area, run with -XX:StackReservedPages=1 and see if we get the
256 // expected warning message for platforms that don't support it.
257 ProcessBuilder pb = ProcessTools.createJavaProcessBuilder("-XX:StackReservedPages=1", "-version");
258 OutputAnalyzer output = new OutputAnalyzer(pb.start());
259 System.out.println("StackReservedPages=1 log: [" + output.getOutput() + "]");
260 if (output.getExitValue() != 0) {
261 String msg = "Could not launch with -XX:StackReservedPages=1: exit " + output.getExitValue();
262 System.err.println("FAILED: " + msg);
263 throw new RuntimeException(msg);
264 }
265
266 isSupportedPlatform = true;
267 String matchStr = "Reserved Stack Area not supported on this platform";
268 int match_idx = output.getOutput().indexOf(matchStr);
269 if (match_idx >= 0) {
270 isSupportedPlatform = false;
271 }
272
273 // Do a sanity check. Some platforms we know are always supported. Make sure
274 // we didn't determine that one of those platforms is not supported.
275 if (!isSupportedPlatform && isAlwaysSupportedPlatform()) {
276 String msg = "This platform should be supported: " + Platform.getOsArch();
277 System.err.println("FAILED: " + msg);
278 throw new RuntimeException(msg);
279 }
280
281 // And some platforms we know are never supported. Make sure
282 // we didn't determine that one of those platforms is supported.
283 if (isSupportedPlatform && isNeverSupportedPlatform()) {
284 String msg = "This platform should not be supported: " + Platform.getOsArch();
285 System.err.println("FAILED: " + msg);
286 throw new RuntimeException(msg);
287 }
288 }
289
290 public static void main(String[] args) throws Exception {
291 initIsSupportedPlatform();
292 for (int i = 0; i < 100; i++) {
293 // Each iteration has to be executed by a new thread. The test
294 // relies on the random size area pushed by the VM at the beginning
295 // of the stack of each Java thread it creates.
296 Thread thread = new Thread(new RunWithSOEContext(new ReentrantLockTest(), 256));
297 thread.start();
298 try {
299 thread.join();
300 } catch (InterruptedException ex) { }
301 }
302 }
303 }