8322818: Thread::getStackTrace can fail with InternalError if virtual…

… thread is timed-parked when pinned

8323002: test/jdk/java/lang/Thread/virtual/stress/GetStackTraceALotWhenPinned.java times out on macosx-x64
8323296: java/lang/Thread/virtual/stress/GetStackTraceALotWhenPinned.java#id1 timed out

Reviewed-by: jpai
Backport-of: 4db7a1c3bb6b56cc7416aa27350406da27fe04a8

src/java.base/share/classes/java/lang/VirtualThread.java

@@ -983,12 +983,12 @@ StackTraceElement[] asyncGetStackTrace() {
      * Returns null if the thread is mounted or in transition.
      */
     private StackTraceElement[] tryGetStackTrace() {
-        int initialState = state();
+        int initialState = state() & ~SUSPENDED;
         switch (initialState) {
             case NEW, STARTED, TERMINATED -> {
                 return new StackTraceElement[0];  // unmounted, empty stack
             }
-            case RUNNING, PINNED -> {
+            case RUNNING, PINNED, TIMED_PINNED -> {
                 return null;   // mounted
             }
             case PARKED, TIMED_PARKED -> {
@@ -1000,7 +1000,7 @@ private StackTraceElement[] tryGetStackTrace() {
             case PARKING, TIMED_PARKING, YIELDING -> {
                 return null;  // in transition
             }
-            default -> throw new InternalError();
+            default -> throw new InternalError("" + initialState);
         }
 
         // thread is unmounted, prevent it from continuing

test/jdk/java/lang/Thread/virtual/stress/GetStackTraceALotWhenPinned.java

@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2023, 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 8322818
+ * @summary Stress test Thread.getStackTrace on a virtual thread that is pinned
+ * @requires vm.debug != true
+ * @modules java.base/java.lang:+open
+ * @library /test/lib
+ * @run main/othervm GetStackTraceALotWhenPinned 500000
+ */
+
+/*
+ * @test
+ * @requires vm.debug == true
+ * @modules java.base/java.lang:+open
+ * @library /test/lib
+ * @run main/othervm/timeout=300 GetStackTraceALotWhenPinned 200000
+ */
+
+import java.time.Instant;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.locks.LockSupport;
+import jdk.test.lib.thread.VThreadRunner;
+
+public class GetStackTraceALotWhenPinned {
+
+    public static void main(String[] args) throws Exception {
+        // need at least two carrier threads when main thread is a virtual thread
+        if (Thread.currentThread().isVirtual()) {
+            VThreadRunner.ensureParallelism(2);
+        }
+
+        int iterations = Integer.parseInt(args[0]);
+        var barrier = new Barrier(2);
+
+        // Start a virtual thread that loops doing Thread.yield and parking while pinned.
+        // This loop creates the conditions for the main thread to sample the stack trace
+        // as it transitions from being unmounted to parking while pinned.
+        var thread = Thread.startVirtualThread(() -> {
+            boolean timed = false;
+            for (int i = 0; i < iterations; i++) {
+                // wait for main thread to arrive
+                barrier.await();
+
+                Thread.yield();
+                synchronized (GetStackTraceALotWhenPinned.class) {
+                    if (timed) {
+                        LockSupport.parkNanos(Long.MAX_VALUE);
+                    } else {
+                        LockSupport.park();
+                    }
+                }
+                timed = !timed;
+            }
+        });
+
+        long lastTimestamp = System.currentTimeMillis();
+        for (int i = 0; i < iterations; i++) {
+            // wait for virtual thread to arrive
+            barrier.await();
+
+            thread.getStackTrace();
+            LockSupport.unpark(thread);
+
+            long currentTime = System.currentTimeMillis();
+            if ((currentTime - lastTimestamp) > 500) {
+                System.out.format("%s %d remaining ...%n", Instant.now(), (iterations - i));
+                lastTimestamp = currentTime;
+            }
+        }
+    }
+
+    /**
+     * Alow threads wait for each other to reach a common barrier point. This class does
+     * not park threads that are waiting for the barrier to trip, instead it spins. This
+     * makes it suitable for tests that use LockSupport.park or Thread.yield.
+     */
+    private static class Barrier {
+        private final int parties;
+        private final AtomicInteger count;
+        private volatile int generation;
+
+        Barrier(int parties) {
+            this.parties = parties;
+            this.count = new AtomicInteger(parties);
+        }
+
+        void await() {
+            int g = generation;
+            if (count.decrementAndGet() == 0) {
+                count.set(parties);
+                generation = g + 1;
+            } else {
+                while (generation == g) {
+                    Thread.onSpinWait();
+                }
+            }
+        }
+
+    }
+}