Bug 39888 - [Android M] Disposing a large amount of sockets while a connect operation is in progress leads to an ART error on Android Marshmallow
Summary: [Android M] Disposing a large amount of sockets while a connect operation is ...
Alias: None
Product: Android
Classification: Xamarin
Component: Mono runtime / AOT Compiler ()
Version: unspecified
Hardware: PC Windows
: --- normal
Target Milestone: ---
Assignee: Jonathan Pryor
Depends on:
Reported: 2016-03-24 14:45 UTC by lukas
Modified: 2017-06-29 08:27 UTC (History)
3 users (show)

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

Simple project containing the bug (12.00 KB, application/x-zip-compressed)
2016-03-24 14:45 UTC, lukas

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Description lukas 2016-03-24 14:45:20 UTC
Created attachment 15517 [details]
Simple project containing the bug

I made an app which needs to scan networks for specific hosts. More precisely I want to create a list of all hosts with whom the connection was successfully established on a specific port.
e.g. find all reachable hosts from to on port 80

The standard timeout for a connect operation is roughly 2 minutes and definitely too high for my purpose. Therefore I had to find a way to set a timeout. The only intended way to do this is by using the static CancelConnectAsync method of the Socket class. See https://msdn.microsoft.com/library/system.net.sockets.socket.cancelconnectasync(v=vs.110).aspx
Xamarin Android however does not support this method. My workaround for this is to forcefully stop the ongoing connect by closing the socket. So far it worked really well. On Android Marshmallow however the app crashes after doing so by no later than 255 times.

I attached a simple test case and created a video of it here:

The log can be found here:

This is probably the most important line.
03-24 10:17:54.031: A/art(1604): art/runtime/fault_handler.cc:117] Check failed: !initialized_