6977677: 3/2 Deadlock on logging subsystem initialization
Summary: Over synchronized Logger.getLogger() deadlocks with LogManager.<clinit>via PlatformLogger
Reviewed-by: dsamersoff, never, acorn, mchung
--- a/jdk/src/share/classes/java/util/logging/Logger.java Mon May 16 17:28:18 2011 +0200
+++ b/jdk/src/share/classes/java/util/logging/Logger.java Mon May 16 12:56:29 2011 -0700
@@ -310,7 +310,20 @@
* @return a suitable Logger
* @throws NullPointerException if the name is null.
*/
- public static synchronized Logger getLogger(String name) {
+
+ // Synchronization is not required here. All synchronization for
+ // adding a new Logger object is handled by LogManager.addLogger().
+ public static Logger getLogger(String name) {
+ // This method is intentionally not a wrapper around a call
+ // to getLogger(name, resourceBundleName). If it were then
+ // this sequence:
+ //
+ // getLogger("Foo", "resourceBundleForFoo");
+ // getLogger("Foo");
+ //
+ // would throw an IllegalArgumentException in the second call
+ // because the wrapper would result in an attempt to replace
+ // the existing "resourceBundleForFoo" with null.
LogManager manager = LogManager.getLogManager();
return manager.demandLogger(name);
}
@@ -355,7 +368,10 @@
* a different resource bundle name.
* @throws NullPointerException if the name is null.
*/
- public static synchronized Logger getLogger(String name, String resourceBundleName) {
+
+ // Synchronization is not required here. All synchronization for
+ // adding a new Logger object is handled by LogManager.addLogger().
+ public static Logger getLogger(String name, String resourceBundleName) {
LogManager manager = LogManager.getLogManager();
Logger result = manager.demandLogger(name);
if (result.resourceBundleName == null) {
@@ -417,7 +433,10 @@
* @throws MissingResourceException if the resourceBundleName is non-null and
* no corresponding resource can be found.
*/
- public static synchronized Logger getAnonymousLogger(String resourceBundleName) {
+
+ // Synchronization is not required here. All synchronization for
+ // adding a new anonymous Logger object is handled by doSetParent().
+ public static Logger getAnonymousLogger(String resourceBundleName) {
LogManager manager = LogManager.getLogManager();
// cleanup some Loggers that have been GC'ed
manager.drainLoggerRefQueueBounded();
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/util/logging/LoggingDeadlock4.java Mon May 16 12:56:29 2011 -0700
@@ -0,0 +1,111 @@
+/*
+ * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 6977677
+ * @summary Deadlock between LogManager.<clinit> and Logger.getLogger()
+ * @author Daniel D. Daugherty
+ * @build LoggingDeadlock4
+ * @run main/timeout=15 LoggingDeadlock4
+ */
+
+import java.awt.Container;
+import java.util.concurrent.CountDownLatch;
+import java.util.logging.LogManager;
+import java.util.logging.Logger;
+
+public class LoggingDeadlock4 {
+ private static CountDownLatch barrier = new CountDownLatch(1);
+ private static CountDownLatch lmIsRunning = new CountDownLatch(1);
+ private static CountDownLatch logIsRunning = new CountDownLatch(1);
+
+ public static void main(String[] args) {
+ System.out.println("main: LoggingDeadlock4 is starting.");
+
+ // Loading the java.awt.Container class will create a
+ // sun.util.logging.PlatformLogger$JavaLogger object
+ // that has to be redirected when the LogManager class
+ // is initialized. This can cause a deadlock between
+ // LogManager.<clinit> and Logger.getLogger().
+ try {
+ Class.forName("java.awt.Container");
+ } catch (ClassNotFoundException cnfe) {
+ throw new RuntimeException("Test failed: could not load"
+ + " java.awt.Container." + cnfe);
+ }
+
+ Thread lmThread = new Thread("LogManagerThread") {
+ public void run() {
+ // let main know LogManagerThread is running
+ lmIsRunning.countDown();
+
+ System.out.println(Thread.currentThread().getName()
+ + ": is running.");
+
+ try {
+ barrier.await(); // wait for race to start
+ } catch (InterruptedException e) {
+ }
+
+ LogManager manager = LogManager.getLogManager();
+ }
+ };
+ lmThread.start();
+
+ Thread logThread = new Thread("LoggerThread") {
+ public void run() {
+ // let main know LoggerThread is running
+ logIsRunning.countDown();
+
+ System.out.println(Thread.currentThread().getName()
+ + ": is running.");
+
+ try {
+ barrier.await(); // wait for race to start
+ } catch (InterruptedException e) {
+ }
+
+ Logger foo = Logger.getLogger("foo logger");
+ }
+ };
+ logThread.start();
+
+ try {
+ // wait for LogManagerThread and LoggerThread to get going
+ lmIsRunning.await();
+ logIsRunning.await();
+ } catch (InterruptedException e) {
+ }
+
+ barrier.countDown(); // start the race
+
+ try {
+ lmThread.join();
+ logThread.join();
+ } catch (InterruptedException ie) {
+ }
+
+ System.out.println("main: LoggingDeadlock4 is done.");
+ }
+}