1 /* 2 * Copyright (c) 2006, 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 6475157 27 * @summary Tests deadlock in simultaneous connection and connector-server close 28 * @author Eamonn McManus 29 */ 30 31 /* This test is somewhat dependent on implementation details. If it suddenly 32 * starts failing after a rewrite of the RMIConnectorServer code, you should 33 * consider whether it is still relevant. 34 */ 35 36 import java.io.IOException; 37 import java.lang.management.ManagementFactory; 38 import java.lang.management.ThreadInfo; 39 import java.lang.management.ThreadMXBean; 40 import java.util.concurrent.Exchanger; 41 import javax.management.MBeanServer; 42 import javax.management.remote.JMXServiceURL; 43 import javax.management.remote.rmi.RMIConnection; 44 import javax.management.remote.rmi.RMIConnectorServer; 45 import javax.management.remote.rmi.RMIJRMPServerImpl; 46 47 public class ConnectorStopDeadlockTest { 48 private static String failure; 49 private static RMIConnectorServer connectorServer; 50 51 public static void main(String[] args) throws Exception { 52 JMXServiceURL url = new JMXServiceURL("service:jmx:rmi://"); 53 MBeanServer mbs = ManagementFactory.getPlatformMBeanServer(); 54 RMIJRMPServerImplSub impl = new RMIJRMPServerImplSub(); 55 56 System.out.println("Creating connectorServer"); 57 connectorServer = new RMIConnectorServer(url, null, impl, mbs); 58 System.out.println("Starting connectorServer"); 59 connectorServer.start(); 60 System.out.println("Making client"); 61 RMIConnection cc = impl.newClient(null); 62 System.out.println("Closing client"); 63 cc.close(); 64 if (connectorServer.isActive()) { 65 System.out.println("Stopping connectorServer"); 66 connectorServer.stop(); 67 } 68 if (failure == null) 69 System.out.println("TEST PASSED, no deadlock"); 70 else 71 System.out.println("TEST FAILED"); 72 } 73 74 static void fail(Throwable e) { 75 System.out.println("FAILED WITH EXCEPTION: " + e); 76 e.printStackTrace(System.out); 77 failure = e.toString(); 78 } 79 80 static void fail(String s) { 81 System.out.println("FAILED: " + s); 82 failure = s; 83 } 84 85 // static MonitorInfo[] threadLocks(Thread t) { 86 // ThreadMXBean tm = ManagementFactory.getThreadMXBean(); 87 // ThreadInfo[] tis = tm.getThreadInfo(new long[] {t.getId()}, true, true); 88 // if (tis[0] == null) 89 // return null; 90 // else 91 // return tis[0].getLockedMonitors(); 92 // } 93 // 94 // static void showLocks(Thread t) { 95 // System.out.println("Locks for " + t.getName() + ":"); 96 // MonitorInfo[] mis = threadLocks(t); 97 // if (mis == null) 98 // System.out.println(" (no longer exists)"); 99 // else if (mis.length == 0) 100 // System.out.println(" (none)"); 101 // else { 102 // for (MonitorInfo mi : mis) 103 // System.out.println(" " + mi); 104 // } 105 // } 106 107 // Wait until thread t blocks waiting for a lock held by the calling thread, 108 // or until it exits. 109 static void waitForBlock(Thread t) { 110 Thread currentThread = Thread.currentThread(); 111 System.out.println("waiting for thread " + t.getName() + " to block " + 112 "on a lock held by thread " + currentThread.getName()); 113 ThreadMXBean tm = ManagementFactory.getThreadMXBean(); 114 while (true) { 115 ThreadInfo ti = tm.getThreadInfo(t.getId()); 116 if (ti == null) { 117 System.out.println(" thread has exited"); 118 return; 119 } 120 if (ti.getLockOwnerId() == currentThread.getId()) { 121 System.out.println(" thread now blocked"); 122 return; 123 } 124 Thread.yield(); 125 } 126 } 127 128 public static class RMIJRMPServerImplSub extends RMIJRMPServerImpl { 129 RMIJRMPServerImplSub() throws IOException { 130 super(0, null, null, null); 131 } 132 133 public RMIConnection makeClient() throws IOException { 134 return super.makeClient("connection id", null); 135 } 136 137 @Override 138 protected void clientClosed(RMIConnection conn) throws IOException { 139 System.out.println("clientClosed, will call connectorServer.stop"); 140 final Exchanger<Void> x = new Exchanger<Void>(); 141 Thread t = new Thread() { 142 public void run() { 143 try { 144 connectorServer.stop(); 145 } catch (Exception e) { 146 fail(e); 147 } 148 } 149 }; 150 t.setName("connectorServer.stop"); 151 t.start(); 152 waitForBlock(t); 153 /* If this thread is synchronized on RMIServerImpl, then 154 * the thread that does connectorServer.stop will acquire 155 * the clientList lock and then block waiting for the RMIServerImpl 156 * lock. Our call to super.clientClosed will then deadlock because 157 * it needs to acquire the clientList lock. 158 */ 159 System.out.println("calling super.clientClosed"); 160 System.out.flush(); 161 super.clientClosed(conn); 162 } 163 } 164 }