1 /*
   2  * Copyright (c) 2015, 2016, 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  * @library /test/lib
  27  * @modules java.base/jdk.internal.misc
  28  * @modules java.base/jdk.internal.vm.annotation
  29  * @run main/othervm -Xint ReservedStackTest
  30  * @run main/othervm -XX:-Inline -XX:CompileCommand=exclude,java/util/concurrent/locks/AbstractOwnableSynchronizer.setExclusiveOwnerThread ReservedStackTest
  31  */
  32 
  33 /* The exclusion of java.util.concurrent.locks.AbstractOwnableSynchronizer.setExclusiveOwnerThread()
  34  * from the compilable methods is required to ensure that the test will be able
  35  * to trigger a StackOverflowError on the right method.
  36  */
  37 
  38 
  39 /*
  40  * Notes about this test:
  41  * This test tries to reproduce a rare but nasty corruption bug that
  42  * occurs when a StackOverflowError is thrown in some critical sections
  43  * of the ReentrantLock implementation.
  44  *
  45  * Here's the critical section where a corruption could occur
  46  * (from java.util.concurrent.ReentrantLock.java)
  47  *
  48  * final void lock() {
  49  *     if (compareAndSetState(0, 1))
  50  *         setExclusiveOwnerThread(Thread.currentThread());
  51  *     else
  52  *         acquire(1);
  53  * }
  54  *
  55  * The corruption occurs when the compareAndSetState(0, 1)
  56  * successfully updates the status of the lock but the method
  57  * fails to set the owner because of a stack overflow.
  58  * HotSpot checks for stack overflow on method invocations.
  59  * The test must trigger a stack overflow either when
  60  * Thread.currentThread() or setExclusiveOwnerThread() is
  61  * invoked.
  62  *
  63  * The test starts with a recursive invocation loop until a
  64  * first StackOverflowError is thrown, the Error is caught
  65  * and a few dozen frames are exited. Now the thread has
  66  * little free space on its execution stack and will try
  67  * to trigger a stack overflow in the critical section.
  68  * The test has a huge array of ReentrantLocks instances.
  69  * The thread invokes a recursive method which, at each
  70  * of its invocations, tries to acquire the next lock
  71  * in the array. The execution continues until a
  72  * StackOverflowError is thrown or the end of the array
  73  * is reached.
  74  * If no StackOverflowError has been thrown, the test
  75  * is non conclusive (recommendation: increase the size
  76  * of the ReentrantLock array).
  77  * The status of all Reentrant locks in the array is checked,
  78  * if a corruption is detected, the test failed, otherwise
  79  * the test passed.
  80  *
  81  * To have a chance that the stack overflow occurs on one
  82  * of the two targeted method invocations, the test is
  83  * repeated in different threads. Each Java thread has a
  84  * random size area allocated at the beginning of its
  85  * stack to prevent false sharing. The test relies on this
  86  * to have different stack alignments when it hits the targeted
  87  * methods (the test could have been written with a native
  88  * method with alloca, but using different Java threads makes
  89  * the test 100% Java).
  90  *
  91  * One additional trick is required to ensure that the stack
  92  * overflow will occur on the Thread.currentThread() getter
  93  * or the setExclusiveOwnerThread() setter.
  94  *
  95  * Potential stack overflows are detected by stack banging,
  96  * at method invocation time.
  97  * In interpreted code, the stack banging performed for the
  98  * lock() method goes further than the stack banging performed
  99  * for the getter or the setter method, so the potential stack
 100  * overflow is detected before entering the critical section.
 101  * In compiled code, the getter and the setter are in-lined,
 102  * so the stack banging is only performed before entering the
 103  * critical section.
 104  * In order to have a stack banging that goes further for the
 105  * getter/setter methods than for the lock() method, the test
 106  * exploits the property that interpreter frames are (much)
 107  * bigger than compiled code frames. When the test is run,
 108  * a compiler option disables the compilation of the
 109  * setExclusiveOwnerThread() method.
 110  *
 111  */
 112 
 113 import java.util.concurrent.locks.ReentrantLock;
 114 import jdk.test.lib.Platform;
 115 
 116 public class ReservedStackTest {
 117 
 118     static class ReentrantLockTest {
 119 
 120         private ReentrantLock lockArray[];
 121         // Frame sizes vary a lot between interpreted code and compiled code
 122         // so the lock array has to be big enough to cover all cases.
 123         // If test fails with message "Not conclusive test", try to increase
 124         // LOCK_ARRAY_SIZE value
 125         private static final int LOCK_ARRAY_SIZE = 8192;
 126         private boolean stackOverflowErrorReceived;
 127         StackOverflowError soe = null;
 128         private int index = -1;
 129 
 130         public void initialize() {
 131             lockArray = new ReentrantLock[LOCK_ARRAY_SIZE];
 132             for (int i = 0; i < LOCK_ARRAY_SIZE; i++) {
 133                 lockArray[i] = new ReentrantLock();
 134             }
 135             stackOverflowErrorReceived = false;
 136         }
 137 
 138         public String getResult() {
 139             if (!stackOverflowErrorReceived) {
 140                 return "ERROR: Not conclusive test: no StackOverflowError received";
 141             }
 142             for (int i = 0; i < LOCK_ARRAY_SIZE; i++) {
 143                 if (lockArray[i].isLocked()) {
 144                     if (!lockArray[i].isHeldByCurrentThread()) {
 145                         StringBuilder s = new StringBuilder();
 146                         s.append("FAILED: ReentrantLock ");
 147                         s.append(i);
 148                         s.append(" looks corrupted");
 149                         return s.toString();
 150                     }
 151                 }
 152             }
 153             return "PASSED";
 154         }
 155 
 156         public void run() {
 157             try {
 158                 lockAndCall(0);
 159             } catch (StackOverflowError e) {
 160                 soe = e;
 161                 stackOverflowErrorReceived = true;
 162             }
 163         }
 164 
 165         private void lockAndCall(int i) {
 166             index = i;
 167             if (i < LOCK_ARRAY_SIZE) {
 168                 lockArray[i].lock();
 169                 lockAndCall(i + 1);
 170             }
 171         }
 172     }
 173 
 174     static class RunWithSOEContext implements Runnable {
 175 
 176         int counter;
 177         int deframe;
 178         int decounter;
 179         int setupSOEFrame;
 180         int testStartFrame;
 181         ReentrantLockTest test;
 182 
 183         public RunWithSOEContext(ReentrantLockTest test, int deframe) {
 184             this.test = test;
 185             this.deframe = deframe;
 186         }
 187 
 188         @Override
 189         @jdk.internal.vm.annotation.ReservedStackAccess
 190         public void run() {
 191             counter = 0;
 192             decounter = deframe;
 193             test.initialize();
 194             recursiveCall();
 195             System.out.println("Framework got StackOverflowError at frame = " + counter);
 196             System.out.println("Test started execution at frame = " + (counter - deframe));
 197             String result = test.getResult();
 198             // The feature is not fully implemented on all platforms,
 199             // corruptions are still possible.
 200             boolean supportedPlatform =
 201                 Platform.isAix() ||
 202                 (Platform.isLinux() &&
 203                   (Platform.isPPC() || Platform.isS390x() || Platform.isX64() ||
 204                    Platform.isX86() || Platform.isAArch64())) ||
 205                 Platform.isOSX() ||
 206                 Platform.isSolaris();
 207             if (supportedPlatform && !result.contains("PASSED")) {
 208                 System.out.println(result);
 209                 throw new Error(result);
 210             } else {
 211                 // Either the test passed or this platform is not supported.
 212                 // On not supported platforms, we only expect the VM to
 213                 // not crash during the test. This is especially important
 214                 // on Windows where the detection of SOE in annotated
 215                 // sections is implemented but the reserved zone mechanism
 216                 // to avoid the corruption cannot be implemented yet
 217                 // because of JDK-8067946
 218                 System.out.println("PASSED");
 219             }
 220         }
 221 
 222         void recursiveCall() {
 223             // Unused local variables to increase the frame size
 224             long l1, l2, l3, l4, l5, l6, l7, l8, l9, l10, l11, l12, l13, l14, l15, l16, l17, l18, l19;
 225             long l20, l21, l22, l23, l24, l25, l26, l27, l28, l30, l31, l32, l33, l34, l35, l36, l37;
 226             counter++;
 227             try {
 228                 recursiveCall();
 229             } catch (StackOverflowError e) {
 230             }
 231             decounter--;
 232             if (decounter == 0) {
 233                 setupSOEFrame = counter;
 234                 testStartFrame = counter - deframe;
 235                 test.run();
 236             }
 237         }
 238     }
 239 
 240     public static void main(String[] args) {
 241         for (int i = 0; i < 1000; i++) {
 242             // Each iteration has to be executed by a new thread. The test
 243             // relies on the random size area pushed by the VM at the beginning
 244             // of the stack of each Java thread it creates.
 245             Thread thread = new Thread(new RunWithSOEContext(new ReentrantLockTest(), 256));
 246             thread.start();
 247             try {
 248                 thread.join();
 249             } catch (InterruptedException ex) { }
 250         }
 251     }
 252 }