Comment # 5 on bug 1184058 from Felix Miata

(In reply to Christophe Giboudeaux from comment #3)
> > Mar 27 03:15:28 hpg33 display-manager[924]: Starting service kdm

> > Distro: openSUSE Tumbleweed 20210321

> That doesn't match.

Just guessing at the meaning of your three words:
# inxi -S
System:    Host: hpg33 Kernel: 5.12.13-1-default x86_64 bits: 64  Distro:
openSUSE Tumbleweed 20210706
# rpm -qa | egrep 'kdm|workspace'
kdebase3-kdm-3.5.10.1-365.42.x86_64
plasma5-workspace-libs-5.22.2.1-1.1.x86_64
plasma5-workspace-5.22.2.1-1.1.x86_64

The problem doesn't depend on the greeter.  The problem does reproduce with no
running DM, with Plasma started via startx instead, with these excerpts from
the exit:

KCrash: Attempting to start /usr/lib64/libexec/drkonqi
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it
was found.
This application failed to start because no Qt platform plugin could be
initialized. Reinstalling the application may fix this problem.
Available platform plugins are .....
Unable to start Dr. Konqi
Re-raising signal for core dump handling.

/var/lib/systemd/coredump/ and /var/crash/ are empty.

(In reply to Christophe Giboudeaux from comment #4)
> > Mar 27 03:17:52 hpg33 kdm[1007]: :0[1007]: pam_unix(xdm:session): session opened for user root(uid=0) by (uid=0)

> Are you trying to log in as root?

That (multiboot; hpg33) box is used for QA and support only. It has no (use
for) users between 499 (messagebus) and 65533 (nobody).