1 /* 2 * Copyright (c) 1998, 1999, 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 26 * @bug 4146462 27 * @summary Priority inversion prevents call to the genSeed method from 28 * returning 29 * 30 * if the test returns, then it passed. 31 * if the test never returns (hangs forever), then it failed. 32 * @key randomness 33 */ 34 35 import java.security.SecureRandom; 36 37 public class Priority_Inversion { 38 public static void main(String args[]) { 39 int deltaPriority = 1; 40 41 if (args.length == 1) { 42 try { 43 deltaPriority = Integer.parseInt(args[0]); 44 } 45 catch (NumberFormatException nfe) { 46 System.err.println 47 ("Sorry, \"" + args[0] + "\" is not a number"); 48 System.exit(1); 49 } 50 } 51 52 RandomTest rand = new RandomTest(); 53 InvertTest invert = new InvertTest(deltaPriority, rand); 54 rand.start(); 55 invert.start(); 56 } 57 } 58 59 class RandomTest extends Thread { 60 public synchronized void run() { 61 System.out.println("Start priority " + getPriority()); 62 // The following should take over a second 63 SecureRandom rand = new SecureRandom(); 64 rand.nextBytes(new byte[5]); 65 } 66 67 void invertPriority() { 68 System.out.println("Waiting ..., priority " + 69 Thread.currentThread().getPriority()); 70 synchronized(this) { 71 } 72 System.out.println("Released Lock"); 73 } 74 } 75 class InvertTest extends Thread { 76 private int delta; 77 private RandomTest rand; 78 79 InvertTest(int delta, RandomTest rand) { 80 this.delta = delta; 81 this.rand = rand; 82 } 83 84 public void run() { 85 setPriority(getPriority() + delta); 86 try { 87 sleep(500); 88 } 89 catch (InterruptedException ie) { } 90 rand.invertPriority(); 91 } 92 }