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.
2026-03-26 17:11:57 -04:00 · 2026-03-26 17:11:57 -04:00 · 0a580b313d
commit 0a580b313d
70422 changed files with 17213626 additions and 0 deletions
--- a/test/jdk/java/lang/ref/EarlyTimeout.java
+++ b/test/jdk/java/lang/ref/EarlyTimeout.java
@ -0,0 +1,104 @@
+/*
+ * Copyright (c) 2014, 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 6853696
+ * @summary ReferenceQueue#remove(timeout) should not return null before
+ *          timeout is elapsed
+ */
+
+import java.lang.InterruptedException;
+import java.lang.System;
+import java.lang.ref.Reference;
+import java.lang.ref.ReferenceQueue;
+import java.lang.ref.WeakReference;
+import java.util.concurrent.CountDownLatch;
+import static java.util.concurrent.TimeUnit.NANOSECONDS;
+
+/**
+ * In order to demonstrate the issue we make several threads (two appears to be sufficient)
+ * to block in ReferenceQueue#remove(timeout) at the same time.
+ * Then, we force a reference to be enqueued by setting its referent to null and calling System.gc().
+ * One of the threads gets the reference returned from the remove().
+ * The other threads get null:
+ * 1) with bug:  this may happen before the specified timeout is elapsed,
+ * 2) without bug:  this can only happen after the timeout is fully elapsed.
+ */
+
+public class EarlyTimeout extends Thread {
+
+    static final int THREADS_COUNT = 2;
+    static final int TIMEOUT = 1000;
+
+    static Object referent = new Object();
+    static final ReferenceQueue<Object> queue = new ReferenceQueue<Object>();
+    static final WeakReference<Object> weakReference = new WeakReference<Object>(referent, queue);
+    static final CountDownLatch startedSignal = new CountDownLatch(THREADS_COUNT);
+
+    long actual;
+    Reference<?> reference;
+
+    public static void main(String[] args) throws Exception {
+        EarlyTimeout[] threads = new EarlyTimeout[THREADS_COUNT];
+        for (int i = 0; i < THREADS_COUNT; ++i) {
+            threads[i] = new EarlyTimeout();
+            threads[i].start();
+        }
+        // The main thread waits until the threads has started and give it a chance
+        // for the threads to block on the queue.remove(TIMEOUT) call
+        startedSignal.await();
+        Thread.sleep(TIMEOUT / 2);
+        referent = null;
+        System.gc();
+        for (EarlyTimeout thread : threads) {
+            thread.join();
+        }
+        if (weakReference.get() != null) {
+            throw new RuntimeException("weakReference was not cleared");
+        }
+        int nonNullRefCount = 0;
+        for (EarlyTimeout thread : threads) {
+            if (thread.reference == null && thread.actual < TIMEOUT) {
+                throw new RuntimeException("elapsed time " + thread.actual
+                        + " is less than timeout " + TIMEOUT);
+            }
+            if (thread.reference != null && thread.reference == weakReference) {
+                nonNullRefCount++;
+            }
+        }
+        if (nonNullRefCount > 1) {
+            throw new RuntimeException("more than one references were removed from queue");
+        }
+    }
+
+    public void run() {
+        try {
+            startedSignal.countDown();
+            long start = System.nanoTime();
+            reference = queue.remove(TIMEOUT);
+            actual = NANOSECONDS.toMillis(System.nanoTime() - start);
+        } catch (InterruptedException ex) {
+            throw new RuntimeException(ex);
+        }
+    }
+}