Yesterday I installed Tumbleweed with KDE Plasma and added Gnome during installation, as I wanted to try if I could get both (I know, probably a bad idea).
This resulted in the lock screen constantly crashing. As I could not find a solution anywhere, I had to find a solution myself which I want to share.
The closest match was this forum entry from 2024.
When locking e.g. with meta+L, the screen showed a message instructing me to unlock with loginctl unlock-session 3 or similar.
This worked, but was very inconvenient.
Upon examining with journalctr --since "2 min ago" I discovered that kscreenlocker_greet was struggling. It complained that fprintd was missing
(something about /usr/lib64/security/pam_fprintd.so: cannot open shared object
and PAM adding faulty module: /usr/lib64/security/pam_fprintd.so.
I don’t remember the exact error message, but they looked similar to the ones in the forum post referenced above.)
I could solve this with zypper install fprintd-pam.
The second error journalctr showed was
kscreenlocker_greet[84400]: pam_pkcs11(kde-smartcard:auth): no suitable token available
After some research into PAM configurations, I decided to remove the option to authorize using a smartcard (which I don’t have) by removing the corresponding config files.
So after a backup I did
cd /usr/lib/pam.d
rm common-auth-smartcard gdm-smartcard kde-smartcard
and hoped for the best. It resolved the issue for me.
Now I can lock and unlock my screen with my password without crashes.
My solution (removing some security related files with sudo) feels intrusive and wrong, so I am very happy about suggestions on how this could be resolved in a better way.
Also, I would appreciate a second opinion whether this compromises my lock screen in a way I missed.
I hope this helps somebody with a similar issue. Thanks for reading.