bug#31925: 'guix substitutes' sometimes hangs on glibc 2.27

[ludo@gnu.org (Ludovic Courtès)]

Hello Andy,

Andy Wingo <wingo@igalia.com> skribis:

> On Thu 05 Jul 2018 14:27, ludo@gnu.org (Ludovic Courtès) writes:
>
>> Hello,
>>
>> Andy Wingo <wingo@igalia.com> skribis:
>>
>>> The signal thread is a possibility though in that case you'd get a
>>> warning; the signal-handling thread appears in scm_all_threads.  Do you
>>> see a warning?  If you do, that is a problem :)
>>
>> I don’t see a warning.
>>
>> But as a Guile user, I shouldn’t see a warning just because there’s a
>> signal thread anyway; it’s not a thread I spawned myself.
>
> I understand but it's how it works.  If we want to change this, probably
> we need a similar interface as we have with finalization.

Right, understood.

>> scheme@(guile-user)> (all-threads)
>> $1 = (#<thread 140488743438080 (1b06c40)> #<thread 140488815434624 (1b06e00)>)
>> scheme@(guile-user)> (when (zero? (primitive-fork)) (primitive-_exit 0))
>> ;; no warning
>
> Are you certain that this is the signal-handling thread and not the
> finalizer thread?  I suspect it is the finalizer thread, and that it
> gets properly shut down before the fork.

Oh, you must be right.

> Regarding seeing the warning: do you do make some other binding for the
> default warning port in Guix?

No.

Thanks,
Ludo’.