1/* 2 * Copyright (c) 2012, 2015, 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 7196045 27 * @bug 8014294 28 * @summary Possible JVM deadlock in ThreadTimesClosure when using HotspotInternal non-public API. 29 * @modules java.management/sun.management 30 * @run main/othervm -XX:+UsePerfData -Xmx32m ThreadCpuTimesDeadlock 31 */ 32 33import java.lang.management.ManagementFactory; 34import javax.management.JMException; 35import javax.management.MBeanServer; 36import javax.management.MalformedObjectNameException; 37import javax.management.ObjectName; 38 39public class ThreadCpuTimesDeadlock { 40 41 public static byte[] dummy; 42 public static long duration = 10 * 1000; 43 private static final String HOTSPOT_INTERNAL = "sun.management:type=HotspotInternal"; 44 45 public static void main(String[] args) { 46 47 MBeanServer server = ManagementFactory.getPlatformMBeanServer(); 48 ObjectName objName= null; 49 try { 50 ObjectName hotspotInternal = new ObjectName(HOTSPOT_INTERNAL); 51 try { 52 server.registerMBean(new sun.management.HotspotInternal(), hotspotInternal); 53 } catch (JMException e) { 54 throw new RuntimeException("HotSpotWatcher: Failed to register the HotspotInternal MBean" + e); 55 } 56 objName= new ObjectName("sun.management:type=HotspotThreading"); 57 58 } catch (MalformedObjectNameException e1) { 59 throw new RuntimeException("Bad object name" + e1); 60 } 61 62 // Thread that allocs memory to generate GC's 63 Thread allocThread = new Thread() { 64 public void run() { 65 while (true) { 66 dummy = new byte[4096]; 67 } 68 } 69 }; 70 71 allocThread.setDaemon(true); 72 allocThread.start(); 73 74 long endTime = System.currentTimeMillis() + duration; 75 long i = 0; 76 while (true) { 77 try { 78 server.getAttribute(objName, "InternalThreadCpuTimes"); 79 } catch (Exception ex) { 80 System.err.println("Exception while getting attribute: " + ex); 81 } 82 i++; 83 if (i % 10000 == 0) { 84 System.out.println("Successful iterations: " + i); 85 } 86 if (System.currentTimeMillis() > endTime) { 87 break; 88 } 89 } 90 System.out.println("PASSED."); 91 } 92} 93