kscreenlocker_greet after a suspend/lock causes a blank unusable screen

[GokulChittaranjan]

UPDATE: I notice this problem even when I leave the system that results in a screen lock - in such a case, the screen remains frozen. So the screen prior to locking can be screen -- inadvertently by an unintended person.

Steps to reproduce the bug (And a workaround to keep working with it):

- Suspend the system (typically the system remains suspended for > 30mins)
- Resume by pressing any key
- A blank screen with a mouse pointer appears

To get back the unlock screen, manually switch to a terminal (e.g. Ctrl + Alt + F3) and then do
- $ ps -Af | grep lock
- $ kill -9 ${PID_OF_kscreenlocker_greet)

Switch back to Ctrl + Alt + F1...

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: plasma-workspace 4:5.19.5-0ubuntu2
ProcVersionSignature: Ubuntu 5.8.0-25.26-generic 5.8.14
Uname: Linux 5.8.0-25-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu50
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: KDE
Date: Fri Oct 30 21:14:36 2020
RebootRequiredPkgs:
 linux-image-5.8.0-26-generic
 linux-base
SourcePackage: plasma-workspace
UpgradeStatus: Upgraded to groovy on 2020-10-27 (3 days ago)
modified.conffile..etc.default.apport: [modified]
mtime.conffile..etc.default.apport: 2020-05-15T11:19:01.372513

[Scarlett Gately Moore (scarlettmoore)]

Upstream bug https://bugs.kde.org/show_bug.cgi?id=479659