Bug 41131 - Stopping a HttpListener throws ObjectDisposedException
Summary: Stopping a HttpListener throws ObjectDisposedException
Alias: None
Product: Class Libraries
Classification: Mono
Component: System ()
Version: master
Hardware: PC Linux
: --- normal
Target Milestone: 4.6.0 (C8)
Assignee: marcos.henrich
Depends on:
Reported: 2016-05-17 13:57 UTC by Robert van der Boon
Modified: 2016-08-15 14:15 UTC (History)
6 users (show)

Tags: C8Beta1
Is this bug a regression?: Yes
Last known good build:

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Description Robert van der Boon 2016-05-17 13:57:11 UTC
Every time I Close() a HttpListener it will throw an ObjectDisposedException from Socket.AcceptAsync, which brings down the process as it is thrown from the ThreadPool.

This is a huge problem for us as we start and stop HttpListeners from our unittests, and this fails with current trunk. (4.4.0-branch @fa2bacc works without error)

Example code:
using System;
using System.Net;
using System.Threading;
namespace TestHttpListener {
   class Program {
      static void Main() {
            HttpListener listener = new HttpListener();
            Console.WriteLine("Press enter to stop this");
            Thread.Sleep(1000); // This sleep is important. Without it the process will (sometimes) have exited.
            Console.WriteLine("Waited and done");
The output is:
Press enter to stop this


Unhandled Exception:
System.ObjectDisposedException: Cannot access a disposed object.
Object name: 'System.Net.Sockets.Socket'.
  at System.Net.Sockets.Socket.ThrowIfDisposedAndClosed () <0x40f880e0 + 0x0004b> in <filename unknown>:0 
  at System.Net.Sockets.Socket.AcceptAsync (System.Net.Sockets.SocketAsyncEventArgs e) <0x40fb3c00 + 0x0001f> in <filename unknown>:0 
  at System.Net.EndPointListener.Accept (System.Net.Sockets.Socket socket, System.Net.Sockets.SocketAsyncEventArgs e) <0x40fb3b60 + 0x00063> in <filename unknown>:0 
  at System.Net.EndPointListener.ProcessAccept (System.Net.Sockets.SocketAsyncEventArgs args) <0x40fb97e0 + 0x00077> in <filename unknown>:0 
  at System.Net.EndPointListener.OnAccept (System.Object sender, System.Net.Sockets.SocketAsyncEventArgs e) <0x40fb97c0 + 0x00013> in <filename unknown>:0 
  at System.Net.Sockets.SocketAsyncEventArgs.OnCompleted (System.Net.Sockets.SocketAsyncEventArgs e) <0x40fb9780 + 0x0002e> in <filename unknown>:0 
  at System.Net.Sockets.SocketAsyncEventArgs.Complete () <0x40fb9760 + 0x00013> in <filename unknown>:0 
  at System.Net.Sockets.Socket.<AcceptAsyncCallback>m__0 (System.IAsyncResult ares) <0x40fb9070 + 0x00383> in <filename unknown>:0 
  at System.Net.Sockets.SocketAsyncResult+<Complete>c__AnonStorey0.<>m__0 (System.Object _) <0x40fb9040 + 0x0001d> in <filename unknown>:0 
  at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem () <0x2aaaac7c39a0 + 0x0002f> in <filename unknown>:0 
  at System.Threading.ThreadPoolWorkQueue.Dispatch () <0x2aaaac7c1f20 + 0x001d6> in <filename unknown>:0 
  at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback () <0x2aaaac7c3820 + 0x00008> in <filename unknown>:0
Comment 1 Robert van der Boon 2016-05-19 11:19:46 UTC
With branch mono-4.4.0-branch/39e87b8 the test program also works.
With master/85c642b it fails.
Comment 2 Romain Flechner 2016-06-08 14:31:13 UTC

I have the same issue in a mobile App.

Xamarin Studio Enterprise
Version 6.1 (build 817)
Installation UUID: 8f939fc0-59c8-428a-aeef-34c176097954
	Mono 4.4.0 (mono-4.4.0-branch/fcf7a6d) (64-bit)
	GTK+ 2.24.23 (Raleigh theme)

	Package version: 404000148

Version: (Xamarin Enterprise)
Hash: 3afb4af
Branch: master
Build date: 2016-04-24 15:13:41-0400

Build Information
Release ID: 601000817
Git revision: 2335763551f9db8296b08542035977b899b7f3b7
Build date: 2016-04-25 10:45:36-04
Xamarin addins: 7f8c9ab2a981143a87fbd5adbde3f5890a838fde
Build lane: monodevelop-lion-cycle8-preview
Comment 3 marcos.henrich 2016-08-09 15:29:53 UTC
I was unable to reproduce this issue on OSX using master e70a8aca1cd575582459db406ab3410e53074b73, mono-4.6.0-branch 5110c098303da1eb8aa08ebad499facc3cc2f56b, mono-4.4.0-branch e6576f8ee1da277d97a5386f13ade6068768245f.

For sanity check I also tried to reproduced with 85c642b5219fe7e7584447766d2d3679303ea8d9 and it failed so my setup should be able to reproduce this, but as it does not fail with recent commits I assume this was fixed on latest C7, C8 and master commits.
Comment 4 akihiko.odaki.4i 2016-08-12 07:41:21 UTC
Reproduced with Xamarin for Visual Studio

I'm not sure how to know the version of Mono runtime, but it says the cause is at:
"1cf254db" is not a revision number in Mono repository, but I hope it is a build ID or something kind of to find the source code.
Comment 5 marcos.henrich 2016-08-12 13:18:07 UTC
@akihiko thanks for reporting that,

1cf254db is a monodroid revision.

I assume this happens while running on android, can you share a simple project where the issue occurs? and the stack trace with the failure?
Comment 6 akihiko.odaki.4i 2016-08-15 14:15:13 UTC
Yes, the code is really simple:

var listener = new System.Net.HttpListener ();
listener.Prefixes.Add ("http://*:8080/");
listener.Start ();
var bytes = System.Text.Encoding.ASCII.GetBytes ("A Proof of Concept for Bug 41131");
var context = listener.GetContext ();
context.Response.OutputStream.Write (bytes, 0, bytes.Length);
context.Response.Close ();
listener.Close ();

Here is the project including binaries. It's about 500MB.

Stack trace:
>	0x21 in System.Net.Sockets.Socket.ThrowIfDisposedAndClosed at /Users/builder/data/lanes/3540/1cf254db/source/mono/mcs/class/System/System.Net.Sockets/Socket.cs:3376,5	C#
 	0x1 in System.Net.Sockets.Socket.Accept at /Users/builder/data/lanes/3540/1cf254db/source/mono/mcs/class/System/System.Net.Sockets/Socket.cs:888,4	C#
 	0x1A in System.Net.Sockets.Socket.AnonymousMethod__1 at /Users/builder/data/lanes/3540/1cf254db/source/mono/mcs/class/System/System.Net.Sockets/Socket.cs:997,6	C#
 	0xC in System.IOSelectorJob.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem at /Users/builder/data/lanes/3540/1cf254db/source/mono/mcs/class/System/System/IOSelector.cs:143,4	C#
 	[External Code]