STEPS TO REPRODUCE
1. lock the screen (Meta+L)
2. switch to tty (Ctrl+Alt+F2), login and type "loginctl unlock-sessions"
3. switch back to graphics
Session must be unlocked
Screenlocker still there
Operating System: Arch Linux
KDE Plasma Version: 5.21.0
KDE Frameworks Version: 5.79.0
Qt Version: 5.15.2
Kernel Version: 5.10.8-112-tkg-upds
OS Type: 64-bit
Graphics Platform: X11
Processors: 12 × Intel® Core™ i7-8700 CPU @ 3.20GHz
Memory: 15.6 GiB of RAM
Graphics Processor: GeForce GTX 1080/PCIe/SSE2
As workaround, I tried to rollback the plasma-workspace package from 5.21.0-1 to 5.20.5-2 and it worked.
Are you using the optional systemd startup feature?
(In reply to Nate Graham from comment #1)
> Are you using the optional systemd startup feature?
Thanks, I thought so. I can confirm this. Raising priority since this effectively locks you out of your session entirely when you hit Bug 433054.
well there's our problem
A possibly relevant merge request was started @ https://invent.kde.org/plasma/kscreenlocker/-/merge_requests/35
Git commit a59f0d75f36fcfccf6ef3a256afbab5143353f7b by David Edmundson.
Committed on 08/05/2021 at 22:59.
Pushed by davidedmundson into branch 'master'.
Port from GetSessionByPid
GetSessionByPid is broken especially when the calling process is in a
different cgroup to the session object.
Rather than using the magic "/auto" object path, calling GetSession with
the argument "auto" seems to work on even distros with old bases and is
the smallest code change.
M +2 -2 logind.cpp