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 != true 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 return Platform.isAix() || 237 (Platform.isLinux() && 238 (Platform.isPPC() || Platform.isS390x() || Platform.isX64() || 239 Platform.isX86() || Platform.isAArch64())) || 240 Platform.isOSX(); 241 } 242 243 private static boolean isNeverSupportedPlatform() { 244 return !isAlwaysSupportedPlatform(); 245 } 246 247 private static boolean isSupportedPlatform; 248 249 private static void initIsSupportedPlatform() throws Exception { 250 // In order to dynamicaly determine if the platform supports the reserved 251 // stack area, run with -XX:StackReservedPages=1 and see if we get the 252 // expected warning message for platforms that don't support it. 253 ProcessBuilder pb = ProcessTools.createJavaProcessBuilder("-XX:StackReservedPages=1", "-version"); 254 OutputAnalyzer output = new OutputAnalyzer(pb.start()); 255 System.out.println("StackReservedPages=1 log: [" + output.getOutput() + "]"); 256 if (output.getExitValue() != 0) { 257 String msg = "Could not launch with -XX:StackReservedPages=1: exit " + output.getExitValue(); 258 System.err.println("FAILED: " + msg); 259 throw new RuntimeException(msg); 260 } 261 262 isSupportedPlatform = true; 263 String matchStr = "Reserved Stack Area not supported on this platform"; 264 int match_idx = output.getOutput().indexOf(matchStr); 265 if (match_idx >= 0) { 266 isSupportedPlatform = false; 267 } 268 269 // Do a sanity check. Some platforms we know are always supported. Make sure 270 // we didn't determine that one of those platforms is not supported. 271 if (!isSupportedPlatform && isAlwaysSupportedPlatform()) { 272 String msg = "This platform should be supported: " + Platform.getOsArch(); 273 System.err.println("FAILED: " + msg); 274 throw new RuntimeException(msg); 275 } 276 277 // And some platforms we know are never supported. Make sure 278 // we didn't determine that one of those platforms is supported. 279 if (isSupportedPlatform && isNeverSupportedPlatform()) { 280 String msg = "This platform should not be supported: " + Platform.getOsArch(); 281 System.err.println("FAILED: " + msg); 282 throw new RuntimeException(msg); 283 } 284 } 285 286 public static void main(String[] args) throws Exception { 287 initIsSupportedPlatform(); 288 for (int i = 0; i < 100; i++) { 289 // Each iteration has to be executed by a new thread. The test 290 // relies on the random size area pushed by the VM at the beginning 291 // of the stack of each Java thread it creates. 292 Thread thread = new Thread(new RunWithSOEContext(new ReentrantLockTest(), 256)); 293 thread.start(); 294 try { 295 thread.join(); 296 } catch (InterruptedException ex) { } 297 } 298 } 299 }