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Details

Type: Bug
Resolution: Done
Priority: Blocker
Fix Version/s: 1.1.4.Final, 1.2.0.CR1
Affects Version/s: 1.1.3.Final, 1.2.0.Beta10
Component/s: Servlet
Labels:
- undertow

Steps to Reproduce:

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The reproduced steps are as follows:

Reproduced steps

Step1. Compile the AsyncDemoServlet.java I have provided
and export a war file called test.war.
Step2. Deploy the test.war to the wildfly.
Step3. check the current connection leak number and
you will found the current connection leak number is 0
Notice: you can use
"lsof -p pid | grep "can't identify protocol" |wc -l"
to check the current connection leak number.
Step4. Access the asynchronous servlet application.
i.e: if you deployed the test.war in your local application server,
and your defalt http listener port is 8000, you can just enter the
url as http://localhost:8080/test/asyncDemoServlet in your browser
to access the web application.
Step5. Click the "Esc" button in your keyboards in five seconds
to terminated the http request.
Step6. check the current connection leak number and
you will found the current connection leak number has
been increased by 1.
Notice: you can use
"lsof -p pid | grep "can't identify protocol" |wc -l"
to check the current connection leak number.

Show
The reproduced steps are as follows: Reproduced steps Step1. Compile the AsyncDemoServlet.java I have provided and export a war file called test.war. Step2. Deploy the test.war to the wildfly. Step3. check the current connection leak number and you will found the current connection leak number is 0 Notice: you can use "lsof -p pid | grep "can't identify protocol" |wc -l" to check the current connection leak number. Step4. Access the asynchronous servlet application. i.e: if you deployed the test.war in your local application server, and your defalt http listener port is 8000, you can just enter the url as http://localhost:8080/test/asyncDemoServlet in your browser to access the web application. Step5. Click the "Esc" button in your keyboards in five seconds to terminated the http request. Step6. check the current connection leak number and you will found the current connection leak number has been increased by 1. Notice: you can use "lsof -p pid | grep "can't identify protocol" |wc -l" to check the current connection leak number.

Description

Phenomenon

When the connection is suddenly terminated during the period we access the asynchronous servlet application, the connection will be leaked. However, the connection won't be leak when we access the synchronous servlet application.

Some of the stacktrace are as follows:

Stacktrace

14:34:23,751 ERROR [io.undertow.request] (default task-22) Blocking request fail
at io.undertow.servlet.spec.HttpServletResponseImpl.responseDone(HttpSer
at io.undertow.servlet.spec.AsyncContextImpl$3.run(AsyncContextImpl.java
at io.undertow.servlet.spec.AsyncContextImpl$6.run(AsyncContextImpl.java
at io.undertow.servlet.spec.AsyncContextImpl$TaskDispatchRunnable.run(As
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor
at java.lang.Thread.run(Thread.java:724) [rt.jar:1.7.0_25]
Caused by: java.io.IOException: Connection reset by peer
at sun.nio.ch.FileDispatcherImpl.write0(Native Method) [rt.jar:1.7.0_25]
at sun.nio.ch.SocketDispatcher.write(SocketDispatcher.java:47) [rt.jar:1
at sun.nio.ch.IOUtil.writeFromNativeBuffer(IOUtil.java:94) [rt.jar:1.7.0
at sun.nio.ch.IOUtil.write(IOUtil.java:51) [rt.jar:1.7.0_25]
at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:466) [rt.ja
at org.xnio.nio.NioSocketConduit.write(NioSocketConduit.java:150)
at io.undertow.server.protocol.http.HttpResponseConduit.processWrite(Htt
at io.undertow.server.protocol.http.HttpResponseConduit.flush(HttpRespon
at io.undertow.conduits.AbstractFixedLengthStreamSinkConduit.flush(Abstr
at org.xnio.conduits.ConduitStreamSinkChannel.flush(ConduitStreamSinkCha
at io.undertow.channels.DetachableStreamSinkChannel.flush(DetachableStre
at org.xnio.channels.Channels.flushBlocking(Channels.java:63)
at io.undertow.servlet.spec.ServletOutputStreamImpl.close(ServletOutputS
at io.undertow.servlet.spec.HttpServletResponseImpl.closeStreamAndWriter
at io.undertow.servlet.spec.HttpServletResponseImpl.responseDone(HttpSer
... 6 more

Here's the test war code you can used to reproduce this phenomenon:

AsyncDemoServlet.java

import java.io.IOException;
import javax.servlet.AsyncContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(urlPatterns="/asyncDemoServlet",asyncSupported=true)
public class AsyncDemoServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        //Execute the business logic in sub-thread.
        AsyncContext ctx = request.startAsync();
        new Thread(new Executor(ctx)).start();
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }

    public class Executor implements Runnable {
        private AsyncContext ctx = null;
        public Executor(AsyncContext ctx){
            this.ctx = ctx;
        }
        public void run(){
            try {
                ctx.getResponse().getOutputStream().write("aaa".getBytes());
                //wait for 5 seconds to simulate the business logic.
                Thread.sleep(5000);
                ctx.getResponse().getOutputStream().flush();
                ctx.complete();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

}

Network connection leak in asynchronous servlet

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