Comment # 4 on bug 1091818 from Freek de Kruijf

(In reply to Wolfgang Bauer from comment #3)
> (In reply to Freek de Kruijf from comment #2)
> > I tried this and indeed I can start a Plasma session, but I consider this
> > still to be a bug. Closing the Wayland session should end all processes
> > which are part of that session.
> 
> And what processes were still running?

After loging in into a Plasma Wayland session, and logging out immediately,
choosing a normal Plasma session and trying to log in, the login screen
reappeared. So I went to tty1 logged in into my account and gave the command
"ps ux", which showed the following output:

USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
freek     2576  0.0  0.2  72992  8272 ?        Ss   09:52   0:00
/usr/lib/systemd/systemd --user
freek     2577  0.0  0.0 118736  3540 ?        S    09:52   0:00 (sd-pam)
freek     2837  0.1  0.5 268759112 22128 ?     SNl  09:52   0:00
/usr/bin/baloo_file
freek     2923  0.0  0.0 241520  3440 ?        Ss   09:52   0:00 gpg-agent
--homedir /home/freek/.gnupg --use-standard-socket --daem
on
freek     2982  0.0  0.0 113028  3576 ?        SLl  09:52   0:00 scdaemon
--multi-server
freek     6100  0.7  0.1  17952  7652 tty1     Ss   09:54   0:00 -bash
freek     9029 50.0  0.0  29812  1588 tty1     R+   09:54   0:00 ps ux

I noticed /usr/bin/baloo_file and did a "lsof -p 2837" which showed some log
files of which .local/share/sddm/xorg-session.log contains:

gpg-agent: a gpg-agent is already running - not starting a new one

After that I killed process 2923 and tried to log in again into the normal
Plasma session, which succeeded. So it seems gpg-agent is the culprit.