Created attachment 827582 [details]
Stack trace of crashed kscreenlocker_greet

Screen locker does not work for NIS accounts.

If I either manually lock the screen with the KDE controls or simply wait a few
minutes until the screen locks itself, it crashes instead. The screen is black
with a message telling that the screen locker is no longer working and how to
resolve the problem from another console by unlocking it from the command line.

I am reproducing the problem with the command

/usr/lib64/libexec/kscreenlocker_greet --testing

for easier debugging.

This results in

[...]
Segmentation fault (core dumped)

It's not related to the NVIDIA driver I am using, because it's exactly the same
without, using NOUVEAU instead.

Also it does not seem to be a KDE only problem, as I also can reproduce it on
other desktops (Gnome, LXDE, XFCE and more).

Seems to be related to NIS. It only crashes when logged in with a NIS account.
Local accounts don't have this problem.

systemd-coredump nicely collects the core dump (can provide this if required)
and it also reports the stack trace into SYSLOG (see attachment).

Happy to supply more information useful for diagnosis.