Bug 441591

Summary: Switching user sometimes results in frozen UI
Product: [Plasma] plasmashell Reporter: safield14
Component: Session ManagementAssignee: Plasma Bugs List <plasma-bugs-null>
Status: RESOLVED WORKSFORME    
Severity: normal CC: joseph, nate, plasma-bugs-null
Priority: NOR Keywords: efficiency-and-performance
Version First Reported In: 5.18.5   
Target Milestone: 1.0   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:

Description safield14 2021-08-26 23:55:28 UTC 
Sometimes when I have two user sessions running, and I try to switch from one to the other, I get a frozen login screen.

I have two running user sessions A and B, and I am currently logged into to B. I then go to "switch user" and choose existing session A, it then sends me to a login screen for A. Once there, the login screen is frozen and I can not log in to A. I can press ctrl+alt+F2/F1 to log back in to session B, but always the login screen will be frozen for session A.

This bug is not reliably reproducible, and happens like 1 in 6 times roughly.

Operating System: Kubuntu 20.04
KDE Plasma Version: 5.18.5
KDE Frameworks Version: 5.68.0
Qt Version: 5.12.8
Kernel Version: 5.11.0-27-generic
OS Type: 64-bit
Processors: 4 × Intel® Core™ i5-4690K CPU @ 3.50GHz
Memory: 15.5 GiB of RAM
Comment 1 Nate Graham 2021-08-28 00:00:39 UTC 
Sadly I'm not sure this is going to be actionable since this code has been extensively modified since Plasma 5.18. :/
Comment 2 safield14 2021-11-29 18:40:44 UTC 
Turns out the UI is not frozen. It sits a black screen for a period of time, and then begins working. The period that the login screen is hung (black), is proportional to how long I was logged in as the other user. If I log in as user A session, then switch to user B session for 5 hours, when I switch back to session A, it will be hung on a black screen for maybe 30 seconds. If I switch back after 3 days, it takes about 8 minutes for the black screen to unfreeze.
Comment 3 Nate Graham 2023-05-17 17:07:57 UTC 
Is this reproducible with Plasma 5.27.5 or later? Also I suspect SDDM could be a cause of this.
Comment 4 Bug Janitor Service 2023-06-01 03:45:25 UTC 
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!
Comment 5 Bug Janitor Service 2023-06-16 03:45:24 UTC 
This bug has been in NEEDSINFO status with no change for at least
30 days. The bug is now closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

Thank you for helping us make KDE software even better for everyone!