Subject: bug#37423: Changing the login service from GDM to SLiM and then back to GDM causes a really bad loop

From: Timothy Sample <[email-masked]>
Date: Tue, 17 Sep 2019 00:45:58 -0400

Hi Jan,

Jan <[email-masked]> writes:

> Hi.
>
> Changing the login service from GDM to SLiM and then back to GDM makes
> GDM to loop like this:
> "New session c1 of user gdm."
> "Removed session c1."
> "New session c2 of user gdm."
> "Removed session c2."
> ...
>
> And it continues like this to relatively high numbers like c167. Didn't
> check how far it could go, but that's not important anyway.
> Reverting to the previous definition of the system by using 
> "guix system switch-generation" or using grub menu entries doesn't help,
> changing /etc/config.scm back to the default gdm configuration and
> running 
> "guix system reconfigure" doesn't help either.

Could this be the same issue as <https://bugs.gnu.org/36508>?  In short,
Guix doesn’t guarantee that the “gdm” user will have the same UID if it
gets deleted and recreated (which happens when you remove the GDM
service and add it again).  You can fix this by ensuring the owner of
the files under “/var/lib/gdm” is the current “gdm” user.

-- Tim