bug#55444: elogind startup race between shepherd and dbus-daemon

[Maxim Cournoyer]

Hi,

Ludovic Courtès <ludo@gnu.org> writes:

> Hello!
>
> Currently (40a729a0e6f1d660b942241416c1e2c567616d4d), shepherd and
> dbus-daemon compete to start elogind: shepherd tries to start it
> eagerly, and dbus-daemon starts it on-demand upon bus activation.
>
> Sometimes dbus-daemon wins, and thus shepherd tries a few times to start
> it anyway, leading to the infamous:
>
>   elogind is already running as PID 123

Do we have a system test that sometimes reproduce it, or at least the
above message?  I have some branch where I introduce some D-Bus
synchronization primitives I had started to fix
https://issues.guix.gnu.org/issue/52051, which ended up being fixed
differently (bumping the timeout value); perhaps it could be of use
here.

Thanks,

Maxim