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/hotspot/jtreg/runtime/handshake/HandshakeDirectTest.java

@@ -0,0 +1,141 @@
+/*
+ * Copyright (c) 2020, 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 HandshakeDirectTest
+ * @bug 8240918
+ * @summary This test tries to stress direct handshakes between threads while suspending them.
+ * @library /testlibrary /test/lib
+ * @build HandshakeDirectTest
+ * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
+ * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI HandshakeDirectTest
+ * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -XX:GuaranteedSafepointInterval=10 -XX:+HandshakeALot -XX:+SafepointALot HandshakeDirectTest
+ */
+
+import jvmti.JVMTIUtils;
+
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.Semaphore;
+import jdk.test.whitebox.WhiteBox;
+import java.io.*;
+
+public class HandshakeDirectTest  implements Runnable {
+    static final int WORKING_THREADS = 32;
+    static final int DIRECT_HANDSHAKES_MARK = 300000;
+    static Thread[] workingThreads = new Thread[WORKING_THREADS];
+    static Object[] locks = new Object[WORKING_THREADS];
+    static AtomicInteger handshakeCount = new AtomicInteger(0);
+
+    static boolean suspendThread(Thread t) {
+        try {
+            JVMTIUtils.suspendThread(t);
+        } catch (JVMTIUtils.JvmtiException e) {
+            if (e.getCode() != JVMTIUtils.JVMTI_ERROR_THREAD_NOT_ALIVE
+                && e.getCode() != JVMTIUtils.JVMTI_ERROR_WRONG_PHASE) {
+                throw e;
+            }
+            return false; // failed to suspend
+        }
+        return true; // suspended
+    }
+
+    static void resumeThread(Thread t) {
+        try {
+            JVMTIUtils.resumeThread(t);
+        } catch (JVMTIUtils.JvmtiException e) {
+            if (e.getCode() != JVMTIUtils.JVMTI_ERROR_THREAD_NOT_ALIVE
+                && e.getCode() != JVMTIUtils.JVMTI_ERROR_WRONG_PHASE) {
+                throw e;
+            }
+        }
+    }
+
+    @Override
+    public void run() {
+        int me = Integer.parseInt(Thread.currentThread().getName());
+        WhiteBox wb = WhiteBox.getWhiteBox();
+
+        while (handshakeCount.get() < DIRECT_HANDSHAKES_MARK) {
+            boolean walked = false;
+            synchronized(locks[me]) {
+                // Handshake directly some other worker
+                int handshakee = ThreadLocalRandom.current().nextInt(0, WORKING_THREADS - 1);
+                if (handshakee == me) {
+                    // Pick another thread instead of me.
+                    handshakee = handshakee != 0 ? handshakee - 1 : handshakee + 1;
+                }
+                // Inflate locks[handshakee] if possible
+                System.identityHashCode(locks[handshakee]);
+                walked = wb.handshakeReadMonitors(workingThreads[handshakee]);
+                if (walked) {
+                    handshakeCount.incrementAndGet();
+                }
+            }
+            locks[me] = new Object();
+        }
+    }
+
+    public static void main(String... args) throws Exception {
+        HandshakeDirectTest test = new HandshakeDirectTest();
+
+        // Initialize locks
+        for (int i = 0; i < WORKING_THREADS; i++) {
+            locks[i] = new Object();
+        }
+
+        // Fire-up working threads.
+        for (int i = 0; i < WORKING_THREADS; i++) {
+            workingThreads[i] = new Thread(test, Integer.toString(i));
+            workingThreads[i].start();
+        }
+
+        // Fire-up suspend-resume thread
+        Thread suspendResumeThread = new Thread() {
+            @Override
+            public void run() {
+                while (true) {
+                    int i = ThreadLocalRandom.current().nextInt(0, WORKING_THREADS - 1);
+                    boolean suspended = suspendThread(workingThreads[i]);
+                    if (!suspended) {
+                        continue; // skip resumeThread call if thread was not suspended
+                    }
+                    try {
+                        Thread.sleep(1); // sleep for 1 ms
+                    } catch(InterruptedException ie) {
+                    }
+                    resumeThread(workingThreads[i]);
+                }
+            }
+        };
+        suspendResumeThread.setDaemon(true);
+        suspendResumeThread.start();
+
+        // Wait until the desired number of direct handshakes is reached
+        // and check that all workers exited
+        for (int i = 0; i < WORKING_THREADS; i++) {
+            workingThreads[i].join();
+        }
+    }
+}