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/System/finalization/FinThreads.java

@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 1998, 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 4026895
+   @summary Ensure that System.runFinalization does not run finalizers in the
+            thread that invokes it
+ */
+
+
+public class FinThreads {
+
+    static Thread mainThread;
+
+    static Object lock = new Object();    /* Protects following two fields */
+    static Thread finalizerThread = null;
+    static Thread finalizedBy = null;
+
+
+    static class Foo {
+
+        boolean catchFinalizer = false;
+
+        /* Instances are only created in an auxiliary thread, in order to
+           guard against stray references from the current thread's stack
+         */
+        public static void create(final boolean catchFinalizer)
+            throws InterruptedException
+        {
+            Thread t = new Thread(new Runnable() {
+                public void run() {
+                    new Foo(catchFinalizer);
+                }});
+            t.start();
+            t.join();
+        }
+
+        public Foo(boolean catchFinalizer) {
+            this.catchFinalizer = catchFinalizer;
+        }
+
+        public void finalize() throws InterruptedException {
+            if (catchFinalizer) {
+                boolean gotFinalizer = false;
+                synchronized (lock) {
+                    if (finalizerThread == null) {
+                        finalizerThread = Thread.currentThread();
+                        gotFinalizer = true;
+                    }
+                }
+                if (gotFinalizer) {
+                    System.err.println("Caught finalizer thread; sleeping...");
+                    Thread.sleep(Long.MAX_VALUE);
+                }
+            } else {
+                synchronized (lock) {
+                    finalizedBy = Thread.currentThread();
+                }
+                System.err.println("Test object finalized by " + finalizedBy);
+            }
+        }
+
+    }
+
+
+    static void alarm(final Thread sleeper, final long delay)
+        throws InterruptedException
+    {
+        Thread t = new Thread(new Runnable() {
+            public void run() {
+                try {
+                    Thread.sleep(delay);
+                    System.err.println("Waking " + sleeper);
+                    sleeper.interrupt();
+                } catch (InterruptedException x) { }
+            }});
+        t.setDaemon(true);
+        t.start();
+    }
+
+
+    public static void main(String[] args) throws Exception {
+
+        mainThread = Thread.currentThread();
+
+        /* Find the finalizer thread and put it to sleep */
+        for (;;) {
+            Foo.create(true);
+            System.gc();
+            synchronized (lock) {
+                if (finalizerThread != null) break;
+            }
+        }
+
+        /* Now create a finalizable object and run finalization */
+        alarm(finalizerThread, 5000);
+        Foo.create(false);
+        for (;;) {
+            System.gc();
+            System.runFinalization();
+            synchronized (lock) {
+                if (finalizedBy != null) break;
+            }
+        }
+
+        if (finalizedBy == mainThread)
+            throw new Exception("Finalizer run in main thread");
+
+    }
+
+}