Eclipse
/
jetty.project
mirror of https://github.com/jetty/jetty.project.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Fixed deadlock in class initialization. (#10540) 

* Thread T1 may initialize HttpTester.Message that extends MutableHttpFields, so grabs the lock for the initialization of class MutableHttpFields.
* Thread T2 may initialize HttpFields, so grabs the lock for HttpFields and initializes field EMPTY, which calls new MutableHttpFields.
* To initialize MutableHttpFields, T1 must initialize HttpFields, but sees that its lock is taken and waits.
* To initialize HttpFields, T2 must create an instance and therefore initialize MutableHttpFields, but sees that its lock is taken and waits.
* Deadlock.

The solution is to use another class, EmptyHttpFields, to initialize HttpFields.EMPTY, so that there is no deadlock.

Signed-off-by: Simone Bordet <simone.bordet@gmail.com>
This commit is contained in:
Simone Bordet 2023-09-18 09:37:03 +02:00 committed by GitHub
parent 09710c7cb6
commit 32227570e5
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 27 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/EmptyHttpFields.java Normal file
View File

@ -0,0 +1,26 @@
//
// ========================================================================
// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License v. 2.0 which is available at
// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
// which is available at https://www.apache.org/licenses/LICENSE-2.0.
//
// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
// ========================================================================
//
package org.eclipse.jetty.http;
import java.util.Collections;
import java.util.ListIterator;
class EmptyHttpFields implements HttpFields
{
@Override
public ListIterator<HttpField> listIterator(int index)
{
return Collections.emptyListIterator();
}
}

2
jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/HttpFields.java
View File

@ -64,7 +64,7 @@ public interface HttpFields extends Iterable<HttpField>, Supplier<HttpFields>
/**
* <p>A constant for an immutable and empty {@link HttpFields}.</p>
*/
HttpFields EMPTY = build().asImmutable();
HttpFields EMPTY = new EmptyHttpFields();
/**
* <p>Returns an empty {@link Mutable} instance.</p>