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/util/concurrent/ConcurrentHashMap/ToArray.java

@@ -0,0 +1,104 @@
+/*
+ * Copyright (c) 2004, 2024, 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 4486658 8010293
+ * @summary thread safety of toArray methods of collection views
+ * @author Martin Buchholz
+ */
+
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+public class ToArray {
+
+    public static void main(String[] args) throws Throwable {
+        final int runsPerTest = Integer.getInteger("jsr166.runsPerTest", 1);
+        final int reps = 10 * runsPerTest;
+        for (int i = reps; i--> 0; )
+            executeTest();
+    }
+
+    static void executeTest() throws Throwable {
+        try (var executor = Executors.newCachedThreadPool()) {
+            final ConcurrentHashMap<Integer, Integer> m = new ConcurrentHashMap<>();
+            final ThreadLocalRandom rnd = ThreadLocalRandom.current();
+            final int nCPU = Runtime.getRuntime().availableProcessors();
+            final int minWorkers = 2;
+            final int maxWorkers = Math.max(minWorkers, Math.min(32, nCPU));
+            final int nWorkers = rnd.nextInt(minWorkers, maxWorkers + 1);
+            final int sizePerWorker = 1024;
+            final int maxSize = nWorkers * sizePerWorker;
+
+            // The foreman busy-checks that the size of the arrays obtained
+            // from the keys and values views grows monotonically until it
+            // reaches the maximum size.
+
+            // NOTE: these size constraints are not specific to toArray and are
+            // applicable to any form of traversal of the collection views
+            CompletableFuture<?> foreman = CompletableFuture.runAsync(new Runnable() {
+                private int prevSize = 0;
+
+                private boolean checkProgress(Object[] a) {
+                    int size = a.length;
+                    if (size < prevSize || size > maxSize)
+                        throw new AssertionError(
+                                String.format("prevSize=%d size=%d maxSize=%d",
+                                        prevSize, size, maxSize));
+                    prevSize = size;
+                    return size == maxSize;
+                }
+
+                public void run() {
+                    Integer[] empty = new Integer[0];
+                    for (; ; )
+                        if (checkProgress(m.values().toArray())
+                                & checkProgress(m.keySet().toArray())
+                                & checkProgress(m.values().toArray(empty))
+                                & checkProgress(m.keySet().toArray(empty)))
+                            return;
+                }
+            }, executor);
+
+            // Each worker puts globally unique keys into the map
+            List<CompletableFuture<?>> workers =
+                    IntStream.range(0, nWorkers)
+                            .mapToObj(w -> (Runnable) () -> {
+                                for (int i = 0, o = w * sizePerWorker; i < sizePerWorker; i++)
+                                    m.put(o + i, i);
+                            })
+                            .map(r -> CompletableFuture.runAsync(r, executor))
+                            .collect(Collectors.toList());
+
+            // Wait for workers and foreman to complete
+            workers.forEach(CompletableFuture<?>::join);
+            foreman.join();
+        }
+    }
+}