EF 6.1.3 Crashing IIS Express with FatalExecutionEngineError in ASP.Net Core MVC

[adam8797]

I (and a few other users) have been experiencing a problem when using EF 6.1.3 and IIS Express. For some reason, sites will crash very inconsistently. Some times, it works, other times it does not.

For the sake of not being redundant, I'll link to a StackOverflow question I put up on the subject, where I go into more detail. Other users are commenting that they have the exact same problem.

https://stackoverflow.com/questions/42772599

I posted this exact issue to the EntityFramework6 Repository and they recommended that I come here looking for ideas.

[odinnix]

Yep, seeing this as well. Super annoying. It seems to be related to IIS Express - is there a git for that?

[danmoseley]

@DamianEdwards where do IIS Express issues go?

[DamianEdwards]

Best place is likely at https://github.com/aspnet/AspNetCoreModule
IIS Express itself isn't open source so doesn't have its own repo, but this will raise it with the right people and is related.

[shirhatti]

@danmosemsft Why do you suspect this is an IIS Express issue? We use the ASP.NET Core Module to host dotnet.exe out of process from the IIS Express process. While we can certainly look into it, there's nothing about a FatalExecutionEngineError in a child process to indicate IIS Express is at fault.

[odinnix]

@shirhatti I actually think this is a Visual Studio debugger issue.

We have been able to work around the issue in two ways:

• dotnet run from the CLI
• Start IIS Express without the debugger attached, and then attach the debugger.

Any thoughts on a better place to post this?

[gkhanna79]

@gregg-miskelly Which is the debugger repo where this issue can be moved to?

[gregg-miskelly]

@gkhanna79 This issue should likely stay here as I don't really remember a 'FatalExecutionEngineError' while debugging issue ever actually being a problem with the debugger.

[gregg-miskelly]

@noahfalk does the CLR have a nob that @dcarl1 can use to get a dump of the problem?

[gkhanna79]

@adam8797 @shirhatti Do you have a repro or a crash dump for the FatalExecutionEngineError?

[adam8797]

@gkhanna79 I can't share the repo as its private to my company, but I can answer questions about it if you have any.

If you've got instructions on how to produce a dump file, I can do so tomorrow.

[gkhanna79]

It will be great if you can try to create a reduced repro. That said, can you use https://blogs.msdn.microsoft.com/cobold/2010/03/01/collecting-crash-dumps/ to see if you can generate the crash dumps? Do note that the crash dump could contain name of your app, filenames and paths, etc, if you are concerned about PII.

[adam8797]

Sounds fine to me. I'll see what I can throw together.

[odinnix]

Likewise. I'm doing some work this evening and will switch back to VS running to see if I can get a crash dump.

[gregg-miskelly]

Unfortunately, none of the techniques in that post will work as your issue only repros while the app is already being debugged by another debugger. Noah may have some suggestions...

[noahfalk]

ProcDump and Windbg can both handle the job, we just need to use them slightly differently than that page describes. Instructions for ProcDump:

1. Download the tool from https://technet.microsoft.com/en-us/sysinternals/dd996900.aspx
2. Unzip/unblock the exe and lets say you put it in C:\temp
3. Trigger the FatalExecutionEngineException popup and then without doing anything further in the VS UI switch to a console window
4. Run: C:\temp\procdump[64].exe -ma [process id]
   If your app that crashed is a 64 bit app then you want to run procdump64, otherwise use procdump. If you aren't sure what bitness the app is an easy way I check from VS is open the debugger modules window and look in the address column. If the addresses are reported with 8 hex digits => 32 bit, 16 hex digits => 64 bit

It should look like this:

c:\Users\Noah\Desktop>procdump.exe -ma 8792

ProcDump v8.2 - Sysinternals process dump utility
Copyright (C) 2009-2016 Mark Russinovich and Andrew Richards
Sysinternals - www.sysinternals.com

[05:47:11] Dump 1 initiated: c:\Users\Noah\Desktop\App1.exe_170421_054711.dmp
[05:47:11] Dump 1 writing: Estimated dump file size is 165 MB.
[05:47:11] Dump 1 complete: 165 MB written in 0.3 seconds
[05:47:11] Dump count reached.

Then just send us that dump and we can take a peak under the hood.