8003833: Spurious NPE from Socket.getIn/OutputStream

Reviewed-by: alanb, dsamersoff

src/share/classes/java/net/AbstractPlainSocketImpl.java

@@ -411,13 +411,12 @@ abstract class AbstractPlainSocketImpl extends SocketImpl
      * Gets an InputStream for this socket.
      */
     protected synchronized InputStream getInputStream() throws IOException {
-        if (isClosedOrPending()) {
+        synchronized (fdLock) {
+            if (isClosedOrPending())
                 throw new IOException("Socket Closed");
-        }
-        if (shut_rd) {
+            if (shut_rd)
                 throw new IOException("Socket input is shutdown");
-        }
-        if (socketInputStream == null) {
+            if (socketInputStream == null)
                 socketInputStream = new SocketInputStream(this);
         }
         return socketInputStream;
@@ -431,13 +430,12 @@ abstract class AbstractPlainSocketImpl extends SocketImpl
      * Gets an OutputStream for this socket.
      */
     protected synchronized OutputStream getOutputStream() throws IOException {
-        if (isClosedOrPending()) {
+        synchronized (fdLock) {
+            if (isClosedOrPending())
                 throw new IOException("Socket Closed");
-        }
-        if (shut_wr) {
+            if (shut_wr)
                 throw new IOException("Socket output is shutdown");
-        }
-        if (socketOutputStream == null) {
+            if (socketOutputStream == null)
                 socketOutputStream = new SocketOutputStream(this);
         }
         return socketOutputStream;

test/java/net/Socket/Streams.java

+/*
+ * Copyright (c) 2012, 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 8003833
+ * @summary Spurious NPE from Socket.getIn/OutputStream
+ */
+
+import java.io.IOException;
+import java.lang.reflect.Constructor;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.util.concurrent.Phaser;
+
+// Racey test, will not always fail, but if it does then there is a problem.
+
+public class Streams {
+    static final int NUM_THREADS = 100;
+    static volatile boolean failed;
+    static final Phaser startingGate = new Phaser(NUM_THREADS + 1);
+
+    public static void main(String[] args) throws Exception {
+
+        try (ServerSocket ss = new ServerSocket(0)) {
+            runTest(OutputStreamGetter.class, ss);
+            runTest(InputStreamGetter.class, ss);
+        }
+
+        if (failed)
+            throw new RuntimeException("Failed, check output");
+    }
+
+    static void runTest(Class<? extends StreamGetter> klass, ServerSocket ss)
+        throws Exception
+    {
+        final int port = ss.getLocalPort();
+        Socket[] sockets = new Socket[NUM_THREADS];
+        for (int i=0; i<NUM_THREADS; i++) {
+            sockets[i] = new Socket("localhost", port);
+            try (Socket socket = ss.accept()) {}
+        }
+
+        Constructor<? extends StreamGetter> ctr = klass.getConstructor(Socket.class);
+
+        Thread[] threads = new Thread[NUM_THREADS];
+        for (int i=0; i<NUM_THREADS; i++)
+            threads[i] = ctr.newInstance(sockets[i]);
+        for (int i=0; i<NUM_THREADS; i++)
+            threads[i].start();
+
+        startingGate.arriveAndAwaitAdvance();
+        for (int i=0; i<NUM_THREADS; i++)
+            sockets[i].close();
+
+        for (int i=0; i<NUM_THREADS; i++)
+            threads[i].join();
+    }
+
+    static abstract class StreamGetter extends Thread {
+        final Socket socket;
+        StreamGetter(Socket s) { socket = s; }
+
+        @Override
+        public void run() {
+            try {
+                startingGate.arriveAndAwaitAdvance();
+                getStream();
+            } catch (IOException x) {
+                // OK, socket may be closed
+            } catch (NullPointerException x) {
+                x.printStackTrace();
+                failed = true;
+            }
+        }
+
+        abstract void getStream() throws IOException;
+    }
+
+    static class InputStreamGetter extends StreamGetter {
+        public InputStreamGetter(Socket s) { super(s); }
+        void getStream() throws IOException {
+            socket.getInputStream();
+        }
+    }
+
+    static class OutputStreamGetter extends StreamGetter {
+        public OutputStreamGetter(Socket s) { super(s); }
+        void getStream() throws IOException {
+            socket.getOutputStream();
+        }
+    }
+}