undefect. CWE-407 — 63 sites patched across 27 ecosystems

Authors: russell@unturf.com · brackishbert@gmail.com · foxhop.net · TimeHexOn.com

Patches, unit tests, benchmarks, whitepaper, and outreach briefs.
Public domain — no copyright claimed. Use freely.

test/jdk/java/lang/Thread/virtual/ParkWithFixedThreadPool.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2021, Tencent. 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
+ * @summary Test virtual thread park when scheduler is a fixed thread pool
+ * @requires vm.continuations
+ * @modules java.base/java.lang:+open
+ * @library /test/lib
+ * @run main ParkWithFixedThreadPool
+ */
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.locks.LockSupport;
+import jdk.test.lib.thread.VThreadScheduler;
+
+public class ParkWithFixedThreadPool {
+    public static void main(String[] args) throws Exception {
+        try (var scheduler = new Scheduler(8)) {
+            int vthreadCount = 300;
+            Thread[] vthreads = new Thread[vthreadCount];
+            Runnable target = new Runnable() {
+                public void run() {
+                    int myIndex = -1;
+                    for (int i = 0; i < vthreadCount; i++) {
+                        if (vthreads[i] == Thread.currentThread()) {
+                            myIndex = i;
+                            break;
+                        }
+                    }
+
+                    if (myIndex > 0) {
+                        LockSupport.unpark(vthreads[myIndex - 1]);
+                    }
+
+                    if (myIndex != (vthreadCount - 1)) {
+                        LockSupport.park();
+                    }
+                }
+            };
+
+            ThreadFactory factory = VThreadScheduler.virtualThreadFactory(scheduler);
+
+            for (int i = 0; i < vthreadCount; i++) {
+                vthreads[i] = factory.newThread(target);
+            }
+            for (int i = 0; i < vthreadCount; i++) {
+                vthreads[i].start();
+            }
+
+            for (int i = 0; i < vthreadCount; i++) {
+                vthreads[i].join();
+            }
+        }
+    }
+
+    static class Scheduler implements Executor, AutoCloseable {
+        private final ExecutorService pool;
+
+        Scheduler(int poolSize) {
+            pool = Executors.newFixedThreadPool(poolSize);
+        }
+
+        @Override
+        public void execute(Runnable task) {
+            try {
+                pool.execute(task);
+            } finally {
+                // ExecutorService::execute may consume parking permit
+                LockSupport.unpark(Thread.currentThread());
+            }
+        }
+
+        @Override
+        public void close() {
+            pool.close();
+        }
+    }
+}