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8151486: Class.forName causes memory leak

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Remove ClassLoader.domains

Reviewed-by: coleenp, dholmes, mchung, naoto
This commit is contained in:
Brent Christian 2016-10-07 12:01:24 -07:00
parent d47b7ffca5
commit 2d52d60a1e
4 changed files with 172 additions and 6 deletions
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6
jdk/src/java.base/share/classes/java/lang/ClassLoader.java
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@ -292,9 +292,6 @@ public abstract class ClassLoader {
new ProtectionDomain(new CodeSource(null, (Certificate[]) null),
null, this, null);
// The initiating protection domains for all classes loaded by this loader
private final Set<ProtectionDomain> domains;
// Invoked by the VM to record every loaded class with this loader.
void addClass(Class<?> c) {
classes.addElement(c);
@ -349,13 +346,11 @@ public abstract class ClassLoader {
if (ParallelLoaders.isRegistered(this.getClass())) {
parallelLockMap = new ConcurrentHashMap<>();
package2certs = new ConcurrentHashMap<>();
domains = Collections.synchronizedSet(new HashSet<>());
assertionLock = new Object();
} else {
// no finer-grained lock; lock on the classloader instance
parallelLockMap = null;
package2certs = new Hashtable<>();
domains = new HashSet<>();
assertionLock = this;
}
}
@ -640,7 +635,6 @@ public abstract class ClassLoader {
}, new AccessControlContext(new ProtectionDomain[] {pd}));
}
}
domains.add(pd);
}
/**

45
jdk/test/java/lang/ClassLoader/forNameLeak/ClassForName.java Normal file
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@ -0,0 +1,45 @@
/*
* Copyright (c) 2016, 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.
*/
import java.net.URLClassLoader;
/*
* This class is loaded by the custom URLClassLoader, and then calls
* Class.forName();
*/
public class ClassForName implements Runnable {
static {
if (!(ClassForName.class.getClassLoader() instanceof URLClassLoader)) {
throw new RuntimeException("Supposed to be loaded by URLClassLoader");
}
}
public void run() {
try {
Class.forName(java.util.List.class.getName(), false,
ClassLoader.getSystemClassLoader());
} catch (Throwable e) {
e.printStackTrace();
}
}
}

121
jdk/test/java/lang/ClassLoader/forNameLeak/ClassForNameLeak.java Normal file
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@ -0,0 +1,121 @@
/*
* Copyright (c) 2016, 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 8151486
* @summary Call Class.forName() on the system classloader from a class loaded
* from a custom classloader.
* @library /lib/testlibrary
* @build jdk.testlibrary.Utils JarUtils
* @build ClassForName ClassForNameLeak
* @run main/othervm/policy=test.policy -Djava.security.manager ClassForNameLeak
*/
import java.lang.ref.PhantomReference;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.net.URL;
import java.net.URLClassLoader;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import jdk.testlibrary.Utils;
/*
* Create .jar, load ClassForName from .jar using a URLClassLoader
*/
public class ClassForNameLeak {
private static final long TIMEOUT = (long)(5000.0 * Utils.TIMEOUT_FACTOR);
private static final String TESTCLASSES = System.getProperty("test.classes", ".");
private static final String CLASSFILENAME = "ClassForName.class";
private static final int THREADS = 10;
private static final ReferenceQueue<ClassLoader> rq = new ReferenceQueue<>();
// Use a new classloader to load the ClassForName class, then run its
// Runnable.
public static PhantomReference<ClassLoader> loadAndRun(Path jarFilePath)
throws Exception {
ClassLoader classLoader = new URLClassLoader(
new URL[]{jarFilePath.toUri().toURL()}) {
@Override public String toString() { return "LeakedClassLoader"; }
};
Class<?> loadClass = Class.forName("ClassForName", true, classLoader);
((Runnable) loadClass.newInstance()).run();
PhantomReference<ClassLoader> ref = new PhantomReference<>(classLoader, rq);
System.out.println("returning phantom ref: " + ref + " to " + classLoader);
return ref;
}
public static void main(final String[] args) throws Exception {
// Create a temporary .jar file containing ClassForName.class
Path testClassesDir = Paths.get(TESTCLASSES);
Path jarFilePath = Files.createTempFile("cfn", ".jar");
JarUtils.createJarFile(jarFilePath, testClassesDir, CLASSFILENAME);
jarFilePath.toFile().deleteOnExit();
// Remove the ClassForName.class file that jtreg built, to make sure
// we're loading from the tmp .jar
Path classFile = FileSystems.getDefault().getPath(TESTCLASSES,
CLASSFILENAME);
Files.delete(classFile);
// Make simultaneous calls to the test method, to stress things a bit
ExecutorService es = Executors.newFixedThreadPool(THREADS);
List<Callable<PhantomReference<ClassLoader>>> callables =
Stream.generate(() -> {
Callable<PhantomReference<ClassLoader>> cprcl = () -> {
return loadAndRun(jarFilePath);
};
return cprcl;
}).limit(THREADS).collect(Collectors.toList());
List<Future<PhantomReference<ClassLoader>>> refs = es.invokeAll(callables);
// Give the GC a chance to enqueue the PhantomReferences
for (int i = 0; i < 10; i++) {
System.gc();
}
// Make sure all PhantomReferences to the leaked classloader are enqueued
for (int j = 0; j < THREADS; j++) {
Reference rmRef = rq.remove(TIMEOUT);
if (rmRef == null) {
throw new RuntimeException("ClassLoader was never enqueued!");
} else {
System.out.println("Enqueued " + rmRef);
}
}
System.out.println("All Classloaders successfully enqued");
}
}

6
jdk/test/java/lang/ClassLoader/forNameLeak/test.policy Normal file
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@ -0,0 +1,6 @@
grant {
permission java.io.FilePermission "<<ALL FILES>>", "read, write, delete";
permission java.lang.RuntimePermission "createClassLoader";
permission java.lang.RuntimePermission "getClassLoader";
permission java.util.PropertyPermission "*", "read"; /* for Utils */
};