bug#65178: Shepherd hangs (was: Getting Guix to shutdown my laptop properly with Sway and no DE)

[Hilton Chain via Bug reports for GNU Guix <bug-guix@gnu.org>]

On Sun, 03 Sep 2023 04:49:35 +0800,
Ludovic Courtès wrote:
>
> Hi!
>
> Hilton Chain <hako@ultrarare.space> scribes:
>
> > On Sun, 13 Aug 2023 23:25:59 +0800,
> > Hilton Chain wrote:
> >>
> >> Today I encountered the home reconfiguration issue.  The behavior is
> >> similar to <https://issues.guix.gnu.org/54919>.
> >
> > And today Shepherd hung after starting a service [1], the service
> > itself started successfully (process started, logs available):
>
> I’m assuming this is shepherd 0.10.2, right?


Yes!


>
> > $ sudo herd enable cloudflare-tunnel && sudo herd start cloudflare-tunnel
> > Enabled service cloudflare-tunnel.
> >
> > [1]: <https://codeberg.org/hako/Rosenthal/src/commit/c7dc95c2932d7362673c28cdc2f52e6bb8357c18/rosenthal/services/child-error.scm#L151>
>
> Is any of the services you’re using doing “non-standard things” such as
> using constructors/destructors other than those provided by shepherd
> (‘make-forkexec-constructor’ et al.)?


No, I'm unaware of such things.


> Is it reproducible, and do you think you could come up with a reduce
> test case (for example by removing services from the config until you
> reach the minimum)?


I still don't know which condition triggers it, so I can't make a test
case.

It's unreproducible.  And I don't think it's really related to the
config, since Shepherd won't hang when rebooting to a system
generation which made it hanging at reconfiguration before.

It might be related to bug#65419 ([Shepherd] Non-reponding service
control fiber) you have reported, since there's similar behavior that
`herd status nscd' still works when Shepherd hangs.