Re: qemu-user-static aarch64 lockup/race? (was Re: Python failure in poudriere on arm64 (via qemu-user-static cross compiling))

On Sun, Jan 28, 2024 at 4:45 PM Nathan Reilly-list <lists@nreilly.com>
wrote:

>
>
> On 29 Jan 2024, at 8:43 am, Guido Falsi <mad@madpilot.net> wrote:
> On 28/01/24 22:34, Guido Falsi wrote:
>
> On 28/01/24 22:23, Warner Losh wrote:
>
> On Sun, Jan 28, 2024, 12:38 PM Guido Falsi <mad@madpilot.net <mailto:
> mad@madpilot.net>> wrote:
>
>     On 28/01/24 15:15, Guido Falsi wrote:
>     [snip]
>      > Creating repository in /tmp/packages:   0%
>      >
>
>     BTW, forgot to mention last time this worked without issue was around
>     20th December.
>
>
> I think this is a bsd-user issue. There is a race somewhere in that code
> that causes the hangs. I'd love a reproducible test case that is somewhat
> smaller than python... there are bigger races with the newer stuff and I've
> not had the time to chase it there either. 😞
>
> First of all thanks for your feedback. It encourages me having someone
> else with better knowledge about this confirm that a race condition is
> actually a possible cause!
> Strange this has not been happening up to mid December.
> My main and fully reproducible use case is actually mostly with pkg.
> at the end of the run poudriere runs `pkg repo` to create the meta files
> and sign the repo. It forks itself (ncpus + 2 I guess, even forcing it to 1
> worker I see three processes), and then locks up, with all the processes
> stopping using CPU (ps output is in my message)
> I guess this can be reproduced with any poudriere repo with at least more
> than ncpus packages in it. can also be reproduced using `poudriere pkgclean
> -u <etc>`
> If that does not work I'm not sure how to reproduce it in other ways, but
> I can try  writing some code mocking what pkg seems to be doing, not an
> expert at such things, though.
>
>
> In case it helps further norrow doen things, It looks like the lockup is
> happening somewhere around here:
>
>
> https://github.com/freebsd/pkg/blob/56fa3f87d9d9644348b89680dfd8af47a860ee82/libpkg/pkg_repo_create.c#L778
>
> and/or in the pkg_create_repo_worker() function here:
>
>
> https://github.com/freebsd/pkg/blob/56fa3f87d9d9644348b89680dfd8af47a860ee82/libpkg/pkg_repo_create.c#L341
>
>
> (I'm trying to spare you the time needed to find the actual code being
> executed, I guess you would have identified this in a few minutes yourself,
> but I'm trying to make myself useful)
>
>
>
> There appears to be a GitHub issue for poudriere with this, but seems to
> be looking in another direction.
>
> https://github.com/freebsd/poudriere/issues/1009
>

There's a FreeBSD bug saying this is happening w/o qemu in the loop.
https://bugs.freebsd.org/276690 at least I think that's similar.

Warner