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/management/ThreadMXBean/LockedMonitorInNative.java

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+/*
+ * Copyright (c) 2024, 2025, 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 ThreadMXBean.getLockedMonitors returns information about an object
+ *    monitor lock entered with a synchronized native method or JNI MonitorEnter
+ * @requires test.thread.factory != "Virtual"
+ * @run junit/othervm LockedMonitorInNative
+ */
+
+import java.lang.management.ManagementFactory;
+import java.lang.management.ThreadInfo;
+import java.lang.management.ThreadMXBean;
+import java.util.Arrays;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.BeforeAll;
+import static org.junit.jupiter.api.Assertions.*;
+
+public class LockedMonitorInNative {
+
+    @BeforeAll
+    static void setup() throws Exception {
+        System.loadLibrary("LockedMonitorInNative");
+    }
+
+    /**
+     * Test ThreadMXBean.getLockedMonitors returns information about an object
+     * monitor lock entered with a synchronized native method.
+     */
+    @Test
+    void testSynchronizedNative() {
+        Object lock = this;
+        runWithSynchronizedNative(() -> {
+            assertTrue(holdsLock(lock), "Thread does not hold lock");
+        });
+    }
+
+    /**
+     * Test ThreadMXBean.getLockedMonitors returns information about an object
+     * monitor lock entered with JNI MonitorEnter.
+     */
+    @Test
+    void testMonitorEnteredInNative() {
+        var lock = new Object();
+        runWithMonitorEnteredInNative(lock, () -> {
+            assertTrue(holdsLock(lock), "Thread does not hold lock");
+        });
+    }
+
+    private boolean holdsLock(Object lock) {
+        int hc = System.identityHashCode(lock);
+        long tid = Thread.currentThread().threadId();
+        ThreadInfo ti = ManagementFactory.getPlatformMXBean(ThreadMXBean.class)
+                .getThreadInfo(new long[] { tid }, true, true)[0];
+        return Arrays.stream(ti.getLockedMonitors())
+                .anyMatch(mi -> mi.getIdentityHashCode() == hc);
+    }
+
+    /**
+     * Invokes the given task's run method while holding the monitor for "this".
+     */
+    private synchronized native void runWithSynchronizedNative(Runnable task);
+
+    /**
+     * Invokes the given task's run method while holding the monitor for the given
+     * object. The monitor is entered with JNI MonitorEnter, and exited with JNI MonitorExit.
+     */
+    private native void runWithMonitorEnteredInNative(Object lock, Runnable task);
+
+    /**
+     * Called from native methods to run the given task.
+     */
+    private void run(Runnable task) {
+        task.run();
+    }
+}