8004138: ForkJoinTask leaks exceptions
Reviewed-by: chegar, mduigou, psandoz, martin
Contributed-by: Doug Lea <dl@cs.oswego.edu>
--- a/jdk/src/share/classes/java/util/concurrent/ForkJoinTask.java Thu Oct 17 13:22:11 2013 -0700
+++ b/jdk/src/share/classes/java/util/concurrent/ForkJoinTask.java Thu Oct 17 12:43:32 2013 -0700
@@ -439,11 +439,13 @@
final Throwable ex;
ExceptionNode next;
final long thrower; // use id not ref to avoid weak cycles
+ final int hashCode; // store task hashCode before weak ref disappears
ExceptionNode(ForkJoinTask<?> task, Throwable ex, ExceptionNode next) {
super(task, exceptionTableRefQueue);
this.ex = ex;
this.next = next;
this.thrower = Thread.currentThread().getId();
+ this.hashCode = System.identityHashCode(task);
}
}
@@ -605,9 +607,9 @@
private static void expungeStaleExceptions() {
for (Object x; (x = exceptionTableRefQueue.poll()) != null;) {
if (x instanceof ExceptionNode) {
- ForkJoinTask<?> key = ((ExceptionNode)x).get();
+ int hashCode = ((ExceptionNode)x).hashCode;
ExceptionNode[] t = exceptionTable;
- int i = System.identityHashCode(key) & (t.length - 1);
+ int i = hashCode & (t.length - 1);
ExceptionNode e = t[i];
ExceptionNode pred = null;
while (e != null) {
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/util/concurrent/forkjoin/FJExceptionTableLeak.java Thu Oct 17 12:43:32 2013 -0700
@@ -0,0 +1,73 @@
+/*
+ * 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.
+ */
+
+/*
+ * This file is available under and governed by the GNU General Public
+ * License version 2 only, as published by the Free Software Foundation.
+ * However, the following notice accompanied the original version of this
+ * file:
+ *
+ * Written by Doug Lea with assistance from members of JCP JSR-166
+ * Expert Group and released to the public domain, as explained at
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+/*
+ * @test
+ * @author Doug Lea
+ * @bug 8004138
+ * @summary Check if ForkJoinPool table leaks thrown exceptions.
+ * @run main/othervm -Xmx32m FJExceptionTableLeak
+ */
+import java.util.concurrent.*;
+
+public class FJExceptionTableLeak {
+
+ // Run with TASKS_PER_STEP * 40 < Xmx < STEPS * TASKS_PER_STEP * 40
+ // These work for Xmx32m:
+ static final int STEPS = 2000;
+ static final int TASKS_PER_STEP = 1000;
+
+ static class FailingTaskException extends RuntimeException {}
+ static class FailingTask extends RecursiveAction {
+ public void compute() {
+ throw new FailingTaskException();
+ }
+ }
+
+ public static void main(String[] args) throws InterruptedException {
+ ForkJoinPool pool = new ForkJoinPool(4);
+ FailingTask[] tasks = new FailingTask[TASKS_PER_STEP];
+ for (int k = 0; k < STEPS; ++k) {
+ for (int i = 0; i < tasks.length; ++i)
+ tasks[i] = new FailingTask();
+ for (int i = 0; i < tasks.length; ++i)
+ pool.execute(tasks[i]);
+ for (int i = 0; i < tasks.length; ++i) {
+ try {
+ tasks[i].join();
+ throw new AssertionError("should throw");
+ } catch (FailingTaskException success) {}
+ }
+ }
+ }
+}