Apache
/
activemq
mirror of https://github.com/apache/activemq.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

AMQ-7353 - fix visibility of marshalledProperties to ensure competing threads don't see partial objects in error. Little test case that demonstrates the problem in isolation

This commit is contained in:
gtully 2019-11-26 16:58:30 +00:00
parent 3f5bb9710a
commit 5a0c853ba0
3 changed files with 216 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
activemq-client/src/main/java/org/apache/activemq/ActiveMQSession.java
View File

@ -746,8 +746,8 @@ public class ActiveMQSession implements Session, QueueSession, TopicSession, Sta
} finally {
connection.removeSession(this);
this.transactionContext = null;
closed = true;
this.transactionContext = null;
}
}
}

2
activemq-client/src/main/java/org/apache/activemq/command/Message.java
View File

@ -79,7 +79,7 @@ public abstract class Message extends BaseCommand implements MarshallAware, Mess
protected String userID;
protected ByteSequence content;
protected ByteSequence marshalledProperties;
protected volatile ByteSequence marshalledProperties;
protected DataStructure dataStructure;
protected int redeliveryCounter;

214
activemq-client/src/test/java/org/apache/activemq/command/VisibilityTest.java Normal file
View File

@ -0,0 +1,214 @@
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* <p>
* http://www.apache.org/licenses/LICENSE-2.0
* <p>
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.activemq.command;
import org.apache.activemq.util.ByteArrayOutputStream;
import org.apache.activemq.util.ByteSequence;
import org.apache.activemq.wireformat.WireFormat;
import org.junit.Ignore;
import org.junit.Test;
import java.io.IOException;
import java.util.HashMap;
import java.util.concurrent.atomic.AtomicBoolean;
import static org.junit.Assert.assertFalse;
// https://issues.apache.org/jira/browse/AMQ-7353
public class VisibilityTest {
// seems to reproduce easily with a direct referene to bytesSequence
// a simpler message LocalMessage with less logic, reproduces ok.
// however adding more logic to org.apache.activemq.command.VisibilityTest.LocalMessage.beforeMarshall will throw it off.
// It could be down to cache lines, it is a brittle test - but it does demonstrate the problem in theory
// an allocation in one thread may not be fully visible in another even after the init has complete!
// I wanted to prove the need for the volatile to avoid the npe, doing the extra work when it is not visible is fine
// but the NPE is a real problem when it happens.
static ActiveMQBytesMessage bytesMessage;
static ByteSequence byteSequence;
static LocalMessage localMessage;
static class LocalMessage {
public HashMap<String, Object> properties = new HashMap<>();
public /* the fix */ volatile ByteSequence marshalledProperties;
public int total;
public void setBooleanProperty(String name, boolean v) {
properties.put(name, v);
}
public void beforeMarshall(WireFormat ignored) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
// putting the following (real work) in and it won't reproduce
//DataOutputStream os = new DataOutputStream(baos);
//MarshallingSupport.marshalPrimitiveMap(properties, os);
//os.close();
total += properties.size();
marshalledProperties = baos.toByteSequence();
}
public ByteSequence getMarshalledProperties() {
return marshalledProperties;
}
}
public static int checkNull() {
ByteSequence local = byteSequence;
if (local != null) {
// if local is non null, the internal buffer may not be visible!
return local.getData().length;
}
return 0;
}
public static int checkNullReference() {
ActiveMQBytesMessage message = bytesMessage;
if (message != null) {
ByteSequence local = message.getMarshalledProperties();
if (local != null) {
// if local is non null, the internal buffer may not be visible!
return local.getData().length;
}
}
return 0;
}
public static int checkNullReferenceOnLocalMessage() {
LocalMessage message = localMessage;
if (message != null) {
ByteSequence local = message.getMarshalledProperties();
if (local != null) {
// if local is non null, the internal buffer may not be visible!
return local.getData().length;
}
}
return 0;
}
@Ignore
public void doTestNested() throws Exception {
final AtomicBoolean gotError = new AtomicBoolean();
final Thread tryingToMarshall = new Thread(new Runnable() {
@Override
public void run() {
long total = 0;
while (!Thread.currentThread().isInterrupted()) {
try {
total += checkNullReference();
} catch (Throwable t) {
t.printStackTrace();
gotError.set(true);
}
}
System.out.println("from other thread " + total);
}
});
long len = 0;
tryingToMarshall.start();
for (int t = 0; t < 10; t++) {
for (int i = 0; i < 1000_000; i++) {
// real world
ActiveMQBytesMessage message = new ActiveMQBytesMessage();
// needs non null properties to init marshalledProperties
message.setBooleanProperty("B", true);
message.beforeMarshall(null);
bytesMessage = message;
// local access after publish
len += message.getMarshalledProperties().getData().length;
}
}
tryingToMarshall.interrupt();
tryingToMarshall.join();
System.out.println(len);
assertFalse("no errors, no npe!", gotError.get());
}
@Test
public void doTestNestedLocalMessage() throws Exception {
final AtomicBoolean gotError = new AtomicBoolean();
final Thread tryingToMarshall = new Thread(new Runnable() {
@Override
public void run() {
long total = 0;
while (!Thread.currentThread().isInterrupted()) {
try {
total += checkNullReferenceOnLocalMessage();
} catch (Throwable t) {
t.printStackTrace();
gotError.set(true);
}
}
System.out.println("from other thread " + total);
}
});
long len = 0;
tryingToMarshall.start();
for (int t = 0; t < 10; t++) {
for (int i = 0; i < 1000_000; i++) {
// real world
LocalMessage message = new LocalMessage();
// needs non null properties to init marshalledProperties
message.setBooleanProperty("B", true);
message.beforeMarshall(null);
localMessage = message;
// local access after publish
len += message.getMarshalledProperties().getData().length;
}
}
tryingToMarshall.interrupt();
tryingToMarshall.join();
System.out.println(len);
assertFalse("no errors, no npe!", gotError.get());
}
@Ignore
public void doTestDirect() throws Exception {
final AtomicBoolean gotError = new AtomicBoolean();
final Thread tryingToMarshall = new Thread(new Runnable() {
@Override
public void run() {
long total = 0;
while (!Thread.currentThread().isInterrupted()) {
try {
total += checkNull();
} catch (Throwable t) {
t.printStackTrace();
gotError.set(true);
}
}
System.out.println("from other thread " + total);
}
});
long len = 0;
tryingToMarshall.start();
for (int t = 0; t < 10; t++) {
for (int i = 0; i < 1000_000; i++) {
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
byteSequence = byteArrayOutputStream.toByteSequence();
// local access after publish
len += byteSequence.getData().length;
}
}
tryingToMarshall.interrupt();
tryingToMarshall.join();
System.out.println(len);
assertFalse("no errors, no npe!", gotError.get());
}
}