8287580: (se) CancelledKeyException during channel registration

Reviewed-by: alanb

src/java.base/share/classes/sun/nio/ch/SelectorImpl.java

@@ -26,6 +26,7 @@
 package sun.nio.ch;
 
 import java.io.IOException;
+import java.nio.channels.CancelledKeyException;
 import java.nio.channels.ClosedSelectorException;
 import java.nio.channels.IllegalSelectorException;
 import java.nio.channels.SelectableChannel;
@@ -225,6 +226,7 @@ public abstract class SelectorImpl
             keys.remove(k);
             k.cancel();
             throw e;
+        } catch (CancelledKeyException ignored) {
         }
         return k;
     }

test/jdk/java/nio/channels/Selector/CancelDuringRegister.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2022, 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 8287580
+ * @summary Check CancelledKeyException not thrown during channel registration
+ * @run main CancelDuringRegister
+ */
+
+import java.nio.channels.*;
+
+public class CancelDuringRegister {
+
+    private static volatile boolean done;
+
+    public static void main(String[] args) throws Exception {
+        try (Selector sel = Selector.open()) {
+
+            // create thread to cancel all keys in the selector's key set
+            var thread = new Thread(() -> {
+                while (!done) {
+                    sel.keys().forEach(SelectionKey::cancel);
+                }
+            });
+            thread.start();
+
+            try (SocketChannel sc = SocketChannel.open()) {
+                sc.configureBlocking(false);
+
+                for (int i = 0; i <100_000; i++) {
+                    // register
+                    var key = sc.register(sel, SelectionKey.OP_READ);
+                    sel.selectNow();
+
+                    // cancel and flush
+                    key.cancel();
+                    do {
+                        sel.selectNow();
+                    } while (sel.keys().contains(key));
+                }
+            } finally {
+                done = true;
+            }
+
+            thread.join();
+        }
+    }
+}