8006395: Race in async socket close on Linux

Reviewed-by: alanb, dsamersoff

src/solaris/native/java/net/linux_close.c

@@ -191,17 +191,6 @@ static int closefd(int fd1, int fd2) {
     pthread_mutex_lock(&(fdEntry->lock));
 
     {
-        /*
-         * Send a wakeup signal to all threads blocked on this
-         * file descriptor.
-         */
-        threadEntry_t *curr = fdEntry->threads;
-        while (curr != NULL) {
-            curr->intr = 1;
-            pthread_kill( curr->thr, sigWakeup );
-            curr = curr->next;
-        }
-
         /*
          * And close/dup the file descriptor
          * (restart if interrupted by signal)
@@ -214,6 +203,16 @@ static int closefd(int fd1, int fd2) {
             }
         } while (rv == -1 && errno == EINTR);
 
+        /*
+         * Send a wakeup signal to all threads blocked on this
+         * file descriptor.
+         */
+        threadEntry_t *curr = fdEntry->threads;
+        while (curr != NULL) {
+            curr->intr = 1;
+            pthread_kill( curr->thr, sigWakeup );
+            curr = curr->next;
+        }
     }
 
     /*

test/java/net/Socket/asyncClose/Race.java

+/*
+ * Copyright (c) 2013, 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 8006395
+ * @summary Race in async socket close on Linux
+ */
+
+import java.io.InputStream;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.net.SocketException;
+import java.util.concurrent.Phaser;
+
+// Racey test, will not always fail, but if it does then we have a problem.
+
+public class Race {
+    final static int THREADS = 100;
+
+    public static void main(String[] args) throws Exception {
+        try (ServerSocket ss = new ServerSocket(0)) {
+            final int port = ss.getLocalPort();
+            final Phaser phaser = new Phaser(THREADS + 1);
+            for (int i=0; i<100; i++) {
+                final Socket s = new Socket("localhost", port);
+                s.setSoLinger(false, 0);
+                try (Socket sa = ss.accept()) {
+                    sa.setSoLinger(false, 0);
+                    final InputStream is = s.getInputStream();
+                    Thread[] threads = new Thread[THREADS];
+                    for (int j=0; j<THREADS; j++) {
+                        threads[j] = new Thread() {
+                        public void run() {
+                            try {
+                                phaser.arriveAndAwaitAdvance();
+                                while (is.read() != -1)
+                                    Thread.sleep(50);
+                            } catch (Exception x) {
+                                if (!(x instanceof SocketException
+                                      && x.getMessage().equals("Socket closed")))
+                                    x.printStackTrace();
+                                // ok, expect Socket closed
+                            }
+                        }};
+                    }
+                    for (int j=0; j<100; j++)
+                        threads[j].start();
+                    phaser.arriveAndAwaitAdvance();
+                    s.close();
+                    for (int j=0; j<100; j++)
+                        threads[j].join();
+                }
+            }
+        }
+    }
+}