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Date: Tue, 29 Sep 2020 14:36:44 -0400
From: Rich Felker <dalias@libc.org>
To: Jesse Hathaway <jesse@mbuki-mvuki.org>
Cc: musl@lists.openwall.com
Message-ID: <20200929183644.GE17637@brightrain.aerifal.cx>
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Subject: Re: [musl] Re: Pending patches for MT-fork stuff

On Tue, Sep 29, 2020 at 01:04:06PM -0500, Jesse Hathaway wrote:
> I was experiencing a hang when calling setreuid from a thread on musl
> 1.2.1 as well as on master with these patches applied. I have attached
> a Go program which hangs when run as the root user outputting only:
> 
>     main.go:31: Calling setreuid
> 
> Whereas with glibc the setreuid call completes successfully, with the
> following output:
> 
>     test.go:31: Calling setreuid
>     test.go:40: Running command
>     test.go:45: root
>     test.go:46: Command complete
> 
> I am happy to help troubleshoot the issue, yours kindly, Jesse

Can you provide an strace (with -f) showing the hang? It's probably
not related to this since fork does not seem to be involved. Depending
on how you're using Go, it may just be Go bypassing libc then trying
to use libc functions, which at least used to be a big problem; I
don't know if it's fixed nowadays or not.

Rich