Comment 23 for bug 1770044

Confirmed on KDE Neon 5.15.1. Might be due to a network printer which was recognized automatically but now no longer exists. The fixes mentioned above (uninstalling the print-manager) appears to work.

[ 5748.844786] plasmashell[10378]: segfault at 0 ip 00007f9c5c597a50 sp 00007ffd24d6a2f0 error 4 in libkcupslib.so[7f9c5c557000+56000]

Also my logs indicate that this might be related to an AppArmor issue with the /usr/sbin/cupsd profile. There are multiple denied entries in the logs whichof I have appended one. Afterwards there is the segfault in libkcupslib.

syslog:Feb 26 18:55:13 matteo-whatever kernel: [ 5090.165402] audit: type=1400 audit(1551203713.010:42): apparmor="DENIED" operation="file_lock" profile="/usr/sbin/cupsd" name="/run/utmp" pid=1420 comm="cupsd" requested_mask="k" denied_mask="k" fsuid=0 ouid=0
syslog:Feb 26 18:58:11 matteo-whatever kernel: [ 5268.663312] plasmashell[4392]: segfault at 0 ip 00007f1ee3c3ea50 sp 00007ffdafee0690 error 4 in libkcupslib.so[7f1ee3bfe000+56000]

After reinstalling the logs have changed and the "denied" entries have been changed into "allowed":
syslog:Feb 26 19:06:11 matteo-whatever kernel: [ 5748.809771] audit: type=1400 audit(1551204371.662:52): apparmor="ALLOWED" operation="capable" profile="/usr/sbin/cupsd" pid=1420 comm="cupsd" capability=12 capname="net_admin"

My system:
Operating System: KDE neon 5.15
KDE Plasma Version: 5.15.1
KDE Frameworks Version: 5.55.0
Qt Version: 5.12.0
Kernel Version: 4.15.12-041512-generic
OS Type: 64-bit
Processors: 8 × Intel® Core™ i7-6700HQ CPU @ 2.60GHz
Memory: 15.5 GiB of RAM