# HG changeset patch # User bpb # Date 1450198966 28800 # Node ID 8566f3f715b07f5518896465f5cee9e1e5df8c29 # Parent 5b58b6cdc196e9c6d57fb6a335c846b489a1ce90 8143394: PushbackReader throws NullPointerException Summary: Synchronize on lock in close() to avoid NPE from read()-close() race. Reviewed-by: alanb, dfuchs diff -r 5b58b6cdc196 -r 8566f3f715b0 jdk/src/java.base/share/classes/java/io/CharArrayReader.java --- a/jdk/src/java.base/share/classes/java/io/CharArrayReader.java Tue Dec 15 08:54:35 2015 -0800 +++ b/jdk/src/java.base/share/classes/java/io/CharArrayReader.java Tue Dec 15 09:02:46 2015 -0800 @@ -1,5 +1,5 @@ /* - * Copyright (c) 1996, 2005, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 1996, 2015, 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 @@ -225,9 +225,12 @@ * Closes the stream and releases any system resources associated with * it. Once the stream has been closed, further read(), ready(), * mark(), reset(), or skip() invocations will throw an IOException. - * Closing a previously closed stream has no effect. + * Closing a previously closed stream has no effect. This method will block + * while there is another thread blocking on the reader. */ public void close() { - buf = null; + synchronized (lock) { + buf = null; + } } } diff -r 5b58b6cdc196 -r 8566f3f715b0 jdk/src/java.base/share/classes/java/io/PushbackReader.java --- a/jdk/src/java.base/share/classes/java/io/PushbackReader.java Tue Dec 15 08:54:35 2015 -0800 +++ b/jdk/src/java.base/share/classes/java/io/PushbackReader.java Tue Dec 15 09:02:46 2015 -0800 @@ -1,5 +1,5 @@ /* - * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 1996, 2015, 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 @@ -241,13 +241,16 @@ * Closes the stream and releases any system resources associated with * it. Once the stream has been closed, further read(), * unread(), ready(), or skip() invocations will throw an IOException. - * Closing a previously closed stream has no effect. + * Closing a previously closed stream has no effect. This method will block + * while there is another thread blocking on the reader. * * @exception IOException If an I/O error occurs */ public void close() throws IOException { - super.close(); - buf = null; + synchronized (lock) { + super.close(); + buf = null; + } } /** diff -r 5b58b6cdc196 -r 8566f3f715b0 jdk/src/java.base/share/classes/java/io/StringReader.java --- a/jdk/src/java.base/share/classes/java/io/StringReader.java Tue Dec 15 08:54:35 2015 -0800 +++ b/jdk/src/java.base/share/classes/java/io/StringReader.java Tue Dec 15 09:02:46 2015 -0800 @@ -1,5 +1,5 @@ /* - * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 1996, 2015, 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 @@ -194,9 +194,12 @@ * Closes the stream and releases any system resources associated with * it. Once the stream has been closed, further read(), * ready(), mark(), or reset() invocations will throw an IOException. - * Closing a previously closed stream has no effect. + * Closing a previously closed stream has no effect. This method will block + * while there is another thread blocking on the reader. */ public void close() { - str = null; + synchronized (lock) { + str = null; + } } } diff -r 5b58b6cdc196 -r 8566f3f715b0 jdk/test/java/io/PushbackReader/ReadCloseRaceNPE.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/jdk/test/java/io/PushbackReader/ReadCloseRaceNPE.java Tue Dec 15 09:02:46 2015 -0800 @@ -0,0 +1,115 @@ +/* + * Copyright (c) 2015, 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 8143394 + * @summary Check for NullPointerException in race between read() and close(). + */ +import java.io.CharArrayReader; +import java.io.IOException; +import java.io.PushbackReader; +import java.io.Reader; +import java.io.StringReader; +import java.util.ArrayList; +import java.util.List; +import java.util.concurrent.atomic.AtomicBoolean; +import java.util.concurrent.atomic.AtomicReference; +import java.util.function.Supplier; + +public class ReadCloseRaceNPE { + + private static final int BUF_SIZE = 1000; + private static final long TIMEOUT_MS = 3000; + + private static final List failures = new ArrayList<>(); + + private static void testReader(final Supplier readerSupplier) + throws InterruptedException { + AtomicReference readerRef = + new AtomicReference<>(readerSupplier.get()); + + AtomicBoolean isFinished = new AtomicBoolean(); + + Runnable readTask = () -> { + long startTime = System.currentTimeMillis(); + while (System.currentTimeMillis() - startTime < TIMEOUT_MS) { + try { + readerRef.get().read(); + } catch (Exception e) { + if (!(e instanceof IOException)) { + failures.add(e); + break; + } + readerRef.set(readerSupplier.get()); + } + } + isFinished.set(true); + }; + + Runnable closeTask = () -> { + while (!isFinished.get()) { + try { + readerRef.get().close(); + } catch (Exception e) { + if (!(e instanceof IOException)) { + e.printStackTrace(); + } + } + } + }; + + Thread readThread = new Thread(readTask); + Thread closeThread = new Thread(closeTask); + + readThread.start(); + closeThread.start(); + readThread.join(); + closeThread.join(); + } + + public static void main(String[] args) throws Throwable { + final String s = "Two riders were approaching.\\n"; + + Supplier charPushbackReaderSupplier = () -> { + char buf[] = new char[s.length()]; + s.getChars(0, s.length(), buf, 0); + CharArrayReader in = new CharArrayReader(buf); + return new PushbackReader(in, BUF_SIZE); + }; + + testReader(charPushbackReaderSupplier); + + Supplier stringPushbackReaderSupplier = () -> { + StringReader in = new StringReader(s); + return new PushbackReader(in, BUF_SIZE); + }; + + testReader(stringPushbackReaderSupplier); + + if (!failures.isEmpty()) { + failures.stream().forEach((x) -> ((Exception) x).printStackTrace()); + throw new RuntimeException("PushbackReaderNPE failed"); + } + } +}