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Created attachment 24406 [details]
Output from Mono SIGSEGV
Here's the version info from Mono:
Mono JIT compiler version 188.8.131.52 (2017-06/6425f06 Fri Jul 28 13:28:44 EDT 2017)
Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
GC: sgen (concurrent by default)
1. Download the Microsoft.NET.Compilers package, version 2.3.1 from NuGet. (https://www.nuget.org/packages/Microsoft.Net.Compilers/2.3.1)
2. AOT compile Microsoft.CodeAnalysis.CSharp.dll (mono --aot ~/.nuget/packages/microsoft.net.compilers/2.3.1/tools/Microsoft.CodeAnalysis.CSharp.dll)
3. Attempt to gather a profile of csc compiling any C# file (even HelloWorld).
Mono SIGSEGVs with the output attached.
This is quite odd as we run same setup for Mono itself
I don't think we run the log profiler for any parts of the build.
Which command are you running to gather the profile?
I have tried the following commands without reproducing the crash:
> wget -O microsoft.net.compilers.2.3.1.nupkg https://www.nuget.org/api/v2/package/Microsoft.Net.Compilers/2.3.1
> unzip microsoft.net.compilers.2.3.1.nupkg
> mono --aot tools/Microsoft.CodeAnalysis.CSharp.dll
> mono --profile=log tools/csc.exe helloworld.cs
The mono version is:
> Mono JIT compiler version 184.108.40.206 (2017-06/6425f06 Fri Jul 28 13:28:44 EDT 2017)
> Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors. www.mono-> project.com
> TLS: normal
> SIGSEGV: altstack
> Notification: kqueue
> Architecture: amd64
> Disabled: none
> Misc: softdebug
> LLVM: yes(3.6.0svn-mono-master/8b1520c)
> GC: sgen (concurrent by default)
I don't think it reproduces with 5.4. I was able to reproduce it with master on Linux. Will be taking a look.
The problem is that we end up trying to access fields on the current domain, but since the profiler's writer thread is a tools thread, mono_domain_get () returns NULL.
We could try fixing this by setting a domain for tools threads.
Moving this to GitHub issues: https://github.com/mono/mono/issues/6188