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/Locking.java

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+/*
+ * Copyright (c) 2019, 2023, 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
+ * @summary Test virtual threads using java.util.concurrent locks
+ * @library /test/lib
+ * @run junit Locking
+ */
+
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.locks.LockSupport;
+import java.util.concurrent.locks.ReentrantLock;
+
+import jdk.test.lib.thread.VThreadRunner;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+
+class Locking {
+
+    /**
+     * Test lock/unlock.
+     */
+    @Test
+    void testReentrantLock1() throws Exception {
+        VThreadRunner.run(() -> {
+            ReentrantLock lock = new ReentrantLock();
+            assertFalse(lock.isHeldByCurrentThread());
+            lock.lock();
+            assertTrue(lock.isHeldByCurrentThread());
+            lock.unlock();
+            assertFalse(lock.isHeldByCurrentThread());
+        });
+    }
+
+    /**
+     * Test tryLock/unlock.
+     */
+    @Test
+    void testReentrantLock2() throws Exception {
+        VThreadRunner.run(() -> {
+            ReentrantLock lock = new ReentrantLock();
+            assertFalse(lock.isHeldByCurrentThread());
+            boolean acquired = lock.tryLock();
+            assertTrue(acquired);
+            assertTrue(lock.isHeldByCurrentThread());
+            lock.unlock();
+            assertFalse(lock.isHeldByCurrentThread());
+        });
+    }
+
+    /**
+     * Test lock/lock/unlock/unlock.
+     */
+    @Test
+    void testReentrantLock3() throws Exception {
+        VThreadRunner.run(() -> {
+            ReentrantLock lock = new ReentrantLock();
+            assertFalse(lock.isHeldByCurrentThread());
+            assertTrue(lock.getHoldCount() == 0);
+            lock.lock();
+            assertTrue(lock.isHeldByCurrentThread());
+            assertTrue(lock.getHoldCount() == 1);
+            lock.lock();
+            assertTrue(lock.isHeldByCurrentThread());
+            assertTrue(lock.getHoldCount() == 2);
+            lock.unlock();
+            assertTrue(lock.isHeldByCurrentThread());
+            assertTrue(lock.getHoldCount() == 1);
+            lock.unlock();
+            assertFalse(lock.isHeldByCurrentThread());
+            assertTrue(lock.getHoldCount() == 0);
+        });
+    }
+
+    /**
+     * Test locked by platform thread, virtual thread tries to lock.
+     */
+    @Test
+    void testReentrantLock4() throws Exception {
+        ReentrantLock lock = new ReentrantLock();
+        var holdsLock = new AtomicBoolean();
+
+        Thread thread;
+
+        // thread acquires lock
+        lock.lock();
+        try {
+            thread = Thread.ofVirtual().start(() -> {
+                lock.lock();  // should block
+                holdsLock.set(true);
+                LockSupport.park();
+                lock.unlock();
+                holdsLock.set(false);
+            });
+            // give time for virtual thread to block
+            Thread.sleep(500);
+            assertFalse(holdsLock.get());
+        } finally {
+            lock.unlock();
+        }
+
+        // virtual thread should acquire lock, park, unpark, and then release lock
+        while (!holdsLock.get()) {
+            Thread.sleep(20);
+        }
+        LockSupport.unpark(thread);
+        while (holdsLock.get()) {
+            Thread.sleep(20);
+        }
+        thread.join();
+    }
+
+    /**
+     * Test locked by virtual thread, platform thread tries to lock.
+     */
+    @Test
+    void testReentrantLock5() throws Exception {
+        ReentrantLock lock = new ReentrantLock();
+        var thread = Thread.ofVirtual().start(() -> {
+            lock.lock();
+            try {
+                LockSupport.park();
+            } finally {
+                lock.unlock();
+            }
+        });
+
+        // wat for virtual thread to acquire lock
+        while (!lock.isLocked()) {
+            Thread.sleep(20);
+        }
+
+        // thread cannot acquire lock
+        try {
+            assertFalse(lock.tryLock());
+        } finally {
+            // virtual thread should unlock
+            LockSupport.unpark(thread);
+
+            // thread should be able to acquire lock
+            lock.lock();
+            lock.unlock();
+            thread.join();
+        }
+    }
+
+    /**
+     * Test locked by virtual thread, another virtual thread tries to lock.
+     */
+    @Test
+    void testReentrantLock6() throws Exception {
+        ReentrantLock lock = new ReentrantLock();
+        var thread1 = Thread.ofVirtual().start(() -> {
+            lock.lock();
+            try {
+                LockSupport.park();
+            } finally {
+                lock.unlock();
+            }
+        });
+
+        // wat for virtual thread to acquire lock
+        while (!lock.isLocked()) {
+            Thread.sleep(10);
+        }
+
+        var holdsLock  = new AtomicBoolean();
+        var thread2 = Thread.ofVirtual().start(() -> {
+            lock.lock();
+            holdsLock.set(true);
+            LockSupport.park();
+            lock.unlock();
+            holdsLock.set(false);
+        });
+
+        // virtual thread2 should block
+        Thread.sleep(1000);
+        assertFalse(holdsLock.get());
+
+        // unpark virtual thread1
+        LockSupport.unpark(thread1);
+
+        // virtual thread2 should acquire lock
+        while (!holdsLock.get()) {
+            Thread.sleep(20);
+        }
+        // unpark virtual thread and it should release lock
+        LockSupport.unpark(thread2);
+        while (holdsLock.get()) {
+            Thread.sleep(20);
+        }
+
+        thread1.join();
+        thread2.join();
+    }
+}