Bug 44919 - SIGABRT when calling UploadStringTaskAsync on WebClient
Summary: SIGABRT when calling UploadStringTaskAsync on WebClient
Alias: None
Product: Runtime
Classification: Mono
Component: io-layer ()
Version: 4.6.0 (C8)
Hardware: PC Linux
: --- normal
Target Milestone: ---
Assignee: Ludovic Henry
Depends on:
Reported: 2016-09-30 09:48 UTC by Dave
Modified: 2016-12-26 23:09 UTC (History)
5 users (show)

Is this bug a regression?: ---
Last known good build:

System.dll (2.39 MB, application/octet-stream)
2016-10-12 19:34 UTC, Dave

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Description Dave 2016-09-30 09:48:25 UTC
After updating from Mono 4.4.2 to 4.6.1, the application I am developing started to crash.

I found that the crash is caused by a SIGABRT when UploadStringTaskAsync is called on System.Net.WebClient. The following simple code is all that is needed to reproduce the crash:

private async Task<string> UploadStringAsync()
		using (var webClient = new WebClient())
			return await webClient.UploadStringTaskAsync("https://www.google.co.uk", "POST", "stuff");

This is a shortened version of the output I get:

* Assertion at socket-io.c:1075, condition `domain->sockaddr_data_field' not met


  at <unknown> <0xffffffff>
  at (wrapper managed-to-native) System.Net.Sockets.Socket.Connect_internal (intptr,System.Net.SocketAddress,int&) <IL 0x00009, 0x000bc>
  at System.Net.Sockets.Socket.Connect_internal (System.Net.Sockets.SafeSocketHandle,System.Net.SocketAddress,int&) <IL 0x0000e, 0x000cb>
  at System.Net.Sockets.Socket.Connect (System.Net.EndPoint) <IL 0x00097, 0x00487>
  at System.Net.WebConnection.Connect (System.Net.HttpWebRequest) <IL 0x001a3, 0x00da7>
  at System.Net.WebConnection.InitConnection (object) <IL 0x00046, 0x003b7>
  at System.Net.WebConnection.<WebConnection>m__0 (object) <IL 0x00002, 0x00067>
  at System.Threading.QueueUserWorkItemCallback.WaitCallback_Context (object) [0x0000e] in /builddir/build/BUILD/mono-4.6.1/mcs/class/referencesource/mscorlib/system/threading/threadpool.cs:1304
  at System.Threading.ExecutionContext.RunInternal (System.Threading.ExecutionContext,System.Threading.ContextCallback,object,bool) [0x0008d] in /builddir/build/BUILD/mono-4.6.1/mcs/class/referencesource/mscorlib/system/threading/executioncontext.cs:957
  at System.Threading.ExecutionContext.Run (System.Threading.ExecutionContext,System.Threading.ContextCallback,object,bool) [0x00000] in /builddir/build/BUILD/mono-4.6.1/mcs/class/referencesource/mscorlib/system/threading/executioncontext.cs:904
  at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem () [0x0002a] in /builddir/build/BUILD/mono-4.6.1/mcs/class/referencesource/mscorlib/system/threading/threadpool.cs:1281
  at System.Threading.ThreadPoolWorkQueue.Dispatch () [0x00096] in /builddir/build/BUILD/mono-4.6.1/mcs/class/referencesource/mscorlib/system/threading/threadpool.cs:854
  at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback () [0x00000] in /builddir/build/BUILD/mono-4.6.1/mcs/class/referencesource/mscorlib/system/threading/threadpool.cs:1209
  at (wrapper runtime-invoke) <Module>.runtime_invoke_bool (object,intptr,intptr,intptr) <IL 0x0001f, 0x00141>


Got a SIGABRT while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries 
used by your application.

I am running Fedora 24.

Please let me know if you need any more info.
Comment 1 Ludovic Henry 2016-10-03 16:51:50 UTC
@marek it looks like a version mismatch between System.dll and the runtime; how could we check that?
The m_Buffer change was introduced by https://github.com/mono/mono/commit/008f7272d35f93696d5f90ec033eca5989a4697f
Comment 2 Marek Safar 2016-10-04 07:11:49 UTC
Could you attach mono --version output

@ludovic: You mean automatically or for this case only?
Comment 3 Dave 2016-10-05 22:01:59 UTC
$ mono --version
Mono JIT compiler version 4.6.1 (Stable Wed Sep 28 13:22:22 UTC 2016)
Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
        TLS:           __thread
        SIGSEGV:       altstack
        Notifications: epoll
        Architecture:  amd64
        Disabled:      none
        Misc:          softdebug 
        LLVM:          supported, not enabled.
        GC:            sgen
Comment 4 Marek Safar 2016-10-06 07:50:12 UTC
Could you also check you are using System.dll from Mono 4.6.1?
Comment 5 Dave 2016-10-07 21:59:51 UTC
How can I check that?
Comment 6 Marek Safar 2016-10-10 14:03:22 UTC
It's probably the best to attach it to the bug report. Just check it's the one which is actually used
Comment 7 Dave 2016-10-12 19:34:20 UTC
Created attachment 18008 [details]

I looked at the references for the project and went to the properties of System.dll, where I found the path to this file.

Assembly version:
Package: .NET Framework 4.6.1
Path: /usr/lib/mono/4.5/System.dll
Comment 8 Dave 2016-11-12 21:27:16 UTC

Were you able to determine if the System.dll file is the correct one?

Comment 9 Marek Safar 2016-11-25 10:05:52 UTC
That assembly looks ok. Could you try Mono 4.8 we made few changes there which should address this sort of issues as well.
Comment 10 Dave 2016-11-25 23:43:48 UTC
Sure, I can give that a go. Thanks very much for investigating!
Comment 11 Dave 2016-12-26 23:09:48 UTC
Seems to work great now, thanks!