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6440846: (cl) Deadlock between AppClassLoader and ExtClassLoader

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Fixed a deadlock between the two class loaders

Reviewed-by: alanb
This commit is contained in:
Valerie Peng 2009-04-06 18:52:03 -07:00
parent c10f593c2c
commit a2a7ded4d4
4 changed files with 221 additions and 55 deletions
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72
jdk/src/share/classes/sun/security/jca/ProviderConfig.java
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@ -1,5 +1,5 @@
/*
* Copyright 2003-2006 Sun Microsystems, Inc. All Rights Reserved.
* Copyright 2003-2009 Sun Microsystems, Inc. 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
@ -60,37 +60,6 @@ final class ProviderConfig {
// use by doLoadProvider()
private final static Class[] CL_STRING = { String.class };
// lock to use while loading a provider. it ensures that each provider
// is loaded only once and that we can detect recursion.
// NOTE that because of 4944382 we use the system classloader as lock.
// By using the same lock to load classes as to load providers we avoid
// deadlock due to lock ordering. However, this class may be initialized
// early in the startup when the system classloader has not yet been set
// up. Use a temporary lock object if that is the case.
// Any of this may break if the class loading implementation is changed.
private static volatile Object LOCK = new Object();
private static Object getLock() {
Object o = LOCK;
// check if lock is already set to the class loader
if (o instanceof ClassLoader) {
return o;
}
Object cl = AccessController.doPrivileged(
new PrivilegedAction<Object>() {
public Object run() {
return ClassLoader.getSystemClassLoader();
}
});
// check if class loader initialized now (non-null)
if (cl != null) {
LOCK = cl;
o = cl;
}
return o;
}
// name of the provider class
private final String className;
@ -194,7 +163,7 @@ final class ProviderConfig {
/**
* Get the provider object. Loads the provider if it is not already loaded.
*/
Provider getProvider() {
synchronized Provider getProvider() {
// volatile variable load
Provider p = provider;
if (p != null) {
@ -203,30 +172,23 @@ final class ProviderConfig {
if (shouldLoad() == false) {
return null;
}
synchronized (getLock()) {
p = provider;
if (p != null) {
// loaded by another thread while we were blocked on lock
return p;
if (isLoading) {
// because this method is synchronized, this can only
// happen if there is recursion.
if (debug != null) {
debug.println("Recursion loading provider: " + this);
new Exception("Call trace").printStackTrace();
}
if (isLoading) {
// because this method is synchronized, this can only
// happen if there is recursion.
if (debug != null) {
debug.println("Recursion loading provider: " + this);
new Exception("Call trace").printStackTrace();
}
return null;
}
try {
isLoading = true;
tries++;
p = doLoadProvider();
} finally {
isLoading = false;
}
provider = p;
return null;
}
try {
isLoading = true;
tries++;
p = doLoadProvider();
} finally {
isLoading = false;
}
provider = p;
return p;
}

35
jdk/test/java/security/Security/ClassLoaderDeadlock/CreateSerialized.java Normal file
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@ -0,0 +1,35 @@
/*
* Copyright 2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
import java.io.*;
import sun.misc.*;
public class CreateSerialized {
public static void main(String[] args) throws Exception {
Object o = new com.sun.crypto.provider.SunJCE();
FileOutputStream fos = new FileOutputStream("object.tmp");
ObjectOutputStream objectOutputStream = new ObjectOutputStream(fos);
objectOutputStream.writeObject(o);
fos.close();
}
}

70
jdk/test/java/security/Security/ClassLoaderDeadlock/Deadlock2.java Normal file
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@ -0,0 +1,70 @@
/*
* Copyright 2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
import java.io.*;
import javax.xml.parsers.DocumentBuilderFactory;
import java.security.*;
public class Deadlock2 {
public static void main(String[] args) throws Exception {
File file = new File("object.tmp");
final byte[] bytes = new byte[(int) file.length()];
FileInputStream fileInputStream = new FileInputStream(file);
int read = fileInputStream.read(bytes);
if (read != file.length()) {
throw new Exception("Didn't read all");
}
Thread.sleep(1000);
Runnable xmlRunnable = new Runnable() {
public void run() {
try {
DocumentBuilderFactory.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
}
};
Runnable readObjectRunnable = new Runnable() {
public void run() {
try {
ObjectInputStream objectInputStream =
new ObjectInputStream(new ByteArrayInputStream(bytes));
Object o = objectInputStream.readObject();
System.out.println(o.getClass());
} catch (Exception e) {
e.printStackTrace();
}
}
}
Thread thread1 = new Thread(readObjectRunnable, "Read Object");
Thread thread2 = new Thread(xmlRunnable, "XML");
thread1.start();
thread2.start();
thread1.join();
thread2.join();
}
}

99
jdk/test/java/security/Security/ClassLoaderDeadlock/Deadlock2.sh Normal file
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@ -0,0 +1,99 @@
#!/bin/sh
#
# Copyright 2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
# CA 95054 USA or visit www.sun.com if you need additional information or
# have any questions.
#
# @test
# @bug 6440846
# @summary make sure we do not deadlock between ExtClassLoader and AppClassLoader
# @author Valerie Peng
# @run shell/timeout=20 Deadlock2.sh
# set a few environment variables so that the shell-script can run stand-alone
# in the source directory
if [ "${TESTSRC}" = "" ] ; then
TESTSRC="."
fi
if [ "${TESTCLASSES}" = "" ] ; then
TESTCLASSES="."
fi
if [ "${TESTJAVA}" = "" ] ; then
echo "TESTJAVA not set. Test cannot execute."
echo "FAILED!!!"
exit 1
fi
# set platform-dependent variables
OS=`uname -s`
case "$OS" in
SunOS )
PATHSEP=":"
FILESEP="/"
;;
Linux )
PATHSEP=":"
FILESEP="/"
;;
Windows* )
PATHSEP=";"
FILESEP="\\"
;;
* )
echo "Unrecognized system!"
exit 1;
;;
esac
# remove old class files
cd ${TESTCLASSES}
rm -f Deadlock2*.class
if [ -d testlib ] ; then
rm -rf testlib
fi
cp -r ${TESTJAVA}${FILESEP}lib${FILESEP}ext testlib
# compile and package the test program
${TESTJAVA}${FILESEP}bin${FILESEP}javac \
-d ${TESTCLASSES} \
${TESTSRC}${FILESEP}CreateSerialized.java \
${TESTSRC}${FILESEP}Deadlock2.java
${TESTJAVA}${FILESEP}bin${FILESEP}jar \
-cvf testlib${FILESEP}Deadlock2.jar \
Deadlock2*.class
rm Deadlock2*.class
# create serialized object and run the test
${TESTJAVA}${FILESEP}bin${FILESEP}java CreateSerialized
${TESTJAVA}${FILESEP}bin${FILESEP}java -Djava.ext.dirs=${TESTCLASSES}${FILESEP}testlib Deadlock2
STATUS=$?
# clean up
rm object.tmp CreateSerialized.class
rm -rf testlib
exit ${STATUS}