1 /*
   2  * Copyright (c) 2015, 2017, 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 import jdk.test.lib.process.ProcessTools;
 116 import jdk.test.lib.process.OutputAnalyzer;
 117 
 118 public class ReservedStackTest {
 119 
 120     static class ReentrantLockTest {
 121 
 122         private ReentrantLock lockArray[];
 123         // Frame sizes vary a lot between interpreted code and compiled code
 124         // so the lock array has to be big enough to cover all cases.
 125         // If test fails with message "Not conclusive test", try to increase
 126         // LOCK_ARRAY_SIZE value
 127         private static final int LOCK_ARRAY_SIZE = 8192;
 128         private boolean stackOverflowErrorReceived;
 129         StackOverflowError soe = null;
 130         private int index = -1;
 131 
 132         public void initialize() {
 133             lockArray = new ReentrantLock[LOCK_ARRAY_SIZE];
 134             for (int i = 0; i < LOCK_ARRAY_SIZE; i++) {
 135                 lockArray[i] = new ReentrantLock();
 136             }
 137             stackOverflowErrorReceived = false;
 138         }
 139 
 140         public String getResult() {
 141             if (!stackOverflowErrorReceived) {
 142                 return "ERROR: Not conclusive test: no StackOverflowError received";
 143             }
 144             for (int i = 0; i < LOCK_ARRAY_SIZE; i++) {
 145                 if (lockArray[i].isLocked()) {
 146                     if (!lockArray[i].isHeldByCurrentThread()) {
 147                         StringBuilder s = new StringBuilder();
 148                         s.append("FAILED: ReentrantLock ");
 149                         s.append(i);
 150                         s.append(" looks corrupted");
 151                         return s.toString();
 152                     }
 153                 }
 154             }
 155             return "PASSED";
 156         }
 157 
 158         public void run() {
 159             try {
 160                 lockAndCall(0);
 161             } catch (StackOverflowError e) {
 162                 soe = e;
 163                 stackOverflowErrorReceived = true;
 164             }
 165         }
 166 
 167         private void lockAndCall(int i) {
 168             index = i;
 169             if (i < LOCK_ARRAY_SIZE) {
 170                 lockArray[i].lock();
 171                 lockAndCall(i + 1);
 172             }
 173         }
 174     }
 175 
 176     static class RunWithSOEContext implements Runnable {
 177 
 178         int counter;
 179         int deframe;
 180         int decounter;
 181         int setupSOEFrame;
 182         int testStartFrame;
 183         ReentrantLockTest test;
 184 
 185         public RunWithSOEContext(ReentrantLockTest test, int deframe) {
 186             this.test = test;
 187             this.deframe = deframe;
 188         }
 189 
 190         @Override
 191         @jdk.internal.vm.annotation.ReservedStackAccess
 192         public void run() {
 193             counter = 0;
 194             decounter = deframe;
 195             test.initialize();
 196             recursiveCall();
 197             System.out.println("Framework got StackOverflowError at frame = " + counter);
 198             System.out.println("Test started execution at frame = " + (counter - deframe));
 199             String result = test.getResult();
 200             // The feature is not fully implemented on all platforms,
 201             // corruptions are still possible.
 202             if (isSupportedPlatform && !result.contains("PASSED")) {
 203                 System.out.println(result);
 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     public 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     public static boolean isNeverSupportedPlatform() {
 248         return !isAlwaysSupportedPlatform() && !Platform.isAArch64();
 249     }
 250 
 251     public static boolean isSupportedPlatform;
 252 
 253     public 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         boolean 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 < 1000; 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 }