8336339: (se) SelectionKey.interestOps(int) should not throw ClosedSelectorException

Reviewed-by: jpai, bpb

src/java.base/linux/classes/sun/nio/ch/EPollSelectorImpl.java

@@ -26,7 +26,6 @@
 package sun.nio.ch;
 
 import java.io.IOException;
-import java.nio.channels.ClosedSelectorException;
 import java.nio.channels.SelectionKey;
 import java.nio.channels.Selector;
 import java.nio.channels.spi.SelectorProvider;
@@ -92,11 +91,6 @@ class EPollSelectorImpl extends SelectorImpl {
         EPoll.ctl(epfd, EPOLL_CTL_ADD, eventfd.efd(), EPOLLIN);
     }
 
-    private void ensureOpen() {
-        if (!isOpen())
-            throw new ClosedSelectorException();
-    }
-
     @Override
     protected int doSelect(Consumer<SelectionKey> action, long timeout)
         throws IOException
@@ -243,7 +237,6 @@ class EPollSelectorImpl extends SelectorImpl {
 
     @Override
     public void setEventOps(SelectionKeyImpl ski) {
-        ensureOpen();
         synchronized (updateLock) {
             updateKeys.addLast(ski);
         }

src/java.base/macosx/classes/sun/nio/ch/KQueueSelectorImpl.java

@@ -26,7 +26,6 @@
 package sun.nio.ch;
 
 import java.io.IOException;
-import java.nio.channels.ClosedSelectorException;
 import java.nio.channels.SelectionKey;
 import java.nio.channels.Selector;
 import java.nio.channels.spi.SelectorProvider;
@@ -97,11 +96,6 @@ class KQueueSelectorImpl extends SelectorImpl {
         KQueue.register(kqfd, fd0, EVFILT_READ, EV_ADD);
     }
 
-    private void ensureOpen() {
-        if (!isOpen())
-            throw new ClosedSelectorException();
-    }
-
     @Override
     protected int doSelect(Consumer<SelectionKey> action, long timeout)
         throws IOException
@@ -285,7 +279,6 @@ class KQueueSelectorImpl extends SelectorImpl {
 
     @Override
     public void setEventOps(SelectionKeyImpl ski) {
-        ensureOpen();
         synchronized (updateLock) {
             updateKeys.addLast(ski);
         }

src/java.base/share/classes/java/nio/channels/spi/AbstractSelectableChannel.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 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
@@ -137,6 +137,8 @@ public abstract class AbstractSelectableChannel
 
     void removeKey(SelectionKey k) {                    // package-private
         synchronized (keyLock) {
+            if (keys == null)
+                return;
             for (int i = 0; i < keys.length; i++)
                 if (keys[i] == k) {
                     keys[i] = null;
@@ -233,7 +235,7 @@ public abstract class AbstractSelectableChannel
                     k.interestOps(ops);
                 } else {
                     // New registration
-                    k = ((AbstractSelector)sel).register(this, ops, att);
+                    k = ((AbstractSelector) sel).register(this, ops, att);
                     addKey(k);
                 }
                 return k;

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

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 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
@@ -188,11 +188,11 @@ public abstract class SelectorImpl
                 // Deregister channels
                 Iterator<SelectionKey> i = keys.iterator();
                 while (i.hasNext()) {
-                    SelectionKeyImpl ski = (SelectionKeyImpl)i.next();
+                    SelectionKeyImpl ski = (SelectionKeyImpl) i.next();
                     deregister(ski);
                     SelectableChannel selch = ski.channel();
                     if (!selch.isOpen() && !selch.isRegistered())
-                        ((SelChImpl)selch).kill();
+                        ((SelChImpl) selch).kill();
                     selectedKeys.remove(ski);
                     i.remove();
                 }
@@ -221,13 +221,14 @@ public abstract class SelectorImpl
         keys.add(k);
         try {
             k.interestOps(ops);
-        } catch (ClosedSelectorException e) {
+        } catch (CancelledKeyException e) {
+            // key observed and cancelled. Okay to return a cancelled key.
+        }
+        if (!isOpen()) {
             assert ch.keyFor(this) == null;
             keys.remove(k);
             k.cancel();
-            throw e;
+            throw new ClosedSelectorException();
-        } catch (CancelledKeyException e) {
-            // key observed and cancelled. Okay to return a cancelled key.
         }
         return k;
     }
@@ -277,7 +278,7 @@ public abstract class SelectorImpl
 
                 SelectableChannel ch = ski.channel();
                 if (!ch.isOpen() && !ch.isRegistered())
-                    ((SelChImpl)ch).kill();
+                    ((SelChImpl) ch).kill();
             }
         }
     }

src/java.base/unix/classes/sun/nio/ch/PollSelectorImpl.java

@@ -231,7 +231,6 @@ class PollSelectorImpl extends SelectorImpl {
 
     @Override
     public void setEventOps(SelectionKeyImpl ski) {
-        ensureOpen();
         synchronized (updateLock) {
             updateKeys.addLast(ski);
         }

src/java.base/windows/classes/sun/nio/ch/WEPollSelectorImpl.java

@@ -28,7 +28,6 @@ package sun.nio.ch;
 import java.io.FileDescriptor;
 import java.io.IOException;
 import java.nio.ByteBuffer;
-import java.nio.channels.ClosedSelectorException;
 import java.nio.channels.Pipe;
 import java.nio.channels.SelectionKey;
 import java.nio.channels.Selector;
@@ -89,11 +88,6 @@ class WEPollSelectorImpl extends SelectorImpl {
         WEPoll.ctl(eph, EPOLL_CTL_ADD, fd0Val, WEPoll.EPOLLIN);
     }
 
-    private void ensureOpen() {
-        if (!isOpen())
-            throw new ClosedSelectorException();
-    }
-
     @Override
     protected int doSelect(Consumer<SelectionKey> action, long timeout)
         throws IOException
@@ -228,7 +222,6 @@ class WEPollSelectorImpl extends SelectorImpl {
 
     @Override
     public void setEventOps(SelectionKeyImpl ski) {
-        ensureOpen();
         synchronized (updateLock) {
             updateKeys.addLast(ski);
         }

src/java.base/windows/classes/sun/nio/ch/WindowsSelectorImpl.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2002, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 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
@@ -606,7 +606,6 @@ class WindowsSelectorImpl extends SelectorImpl {
 
     @Override
     public void setEventOps(SelectionKeyImpl ski) {
-        ensureOpen();
         synchronized (updateLock) {
             updateKeys.addLast(ski);
         }

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

@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 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 8336339
+ * @summary Race registration and selection key updates with Selector.close
+ * @run junit RaceUpdatesAndClose
+ */
+
+import java.nio.channels.CancelledKeyException;
+import java.nio.channels.ClosedSelectorException;
+import java.nio.channels.DatagramChannel;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.Selector;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Phaser;
+
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.RepeatedTest;
+
+class RaceUpdatesAndClose {
+    private static ExecutorService executor;
+
+    @BeforeAll
+    static void setup() throws Exception {
+        executor = Executors.newFixedThreadPool(2);
+    }
+
+    @AfterAll
+    static void finish() {
+        executor.shutdown();
+    }
+
+    /**
+     * Race SelectableChannel.register and Selector.close.
+     */
+    @RepeatedTest(100)
+    void raceRegisterAndClose() throws Exception {
+        try (Selector sel = Selector.open();
+             DatagramChannel dc = DatagramChannel.open()) {
+
+            dc.configureBlocking(false);
+
+            Phaser phaser = new Phaser(2);
+
+            // register
+            var task1 = executor.submit(() -> {
+                phaser.arriveAndAwaitAdvance();
+                try {
+                    dc.register(sel, SelectionKey.OP_READ);
+                } catch (ClosedSelectorException e) { }
+                return null;
+            });
+
+            // close selector
+            var task2 = executor.submit(() -> {
+                phaser.arriveAndAwaitAdvance();
+                sel.close();
+                return null;
+            });
+
+            task1.get();
+            task2.get();
+        }
+    }
+
+    /**
+     * Race SelectionKey.interestOps and Selector.close.
+     */
+    @RepeatedTest(100)
+    void raceInterestOpsAndClose() throws Exception {
+        try (Selector sel = Selector.open();
+             DatagramChannel dc = DatagramChannel.open()) {
+
+            dc.configureBlocking(false);
+            SelectionKey key = dc.register(sel, SelectionKey.OP_READ);
+
+            Phaser phaser = new Phaser(2);
+
+            // interestOps
+            var task1 = executor.submit(() -> {
+                phaser.arriveAndAwaitAdvance();
+                try {
+                    key.interestOps(0);
+                } catch (CancelledKeyException e) { }
+            });
+
+            // close selector
+            var task2 = executor.submit(() -> {
+                phaser.arriveAndAwaitAdvance();
+                sel.close();
+                return null;
+            });
+
+            task1.get();
+            task2.get();
+        }
+    }
+}