Bug 508662 - Switching user causes hard system freeze requiring forced reboot
Summary: Switching user causes hard system freeze requiring forced reboot
Status: RESOLVED WORKSFORME
Alias: None
Product: plasmashell
Classification: Plasma
Component: Lock/logout widget (other bugs)
Version First Reported In: 6.4.4
Platform: Other Linux
: NOR major
Target Milestone: 1.0
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2025-08-23 21:55 UTC by Sylens
Modified: 2025-10-16 03:47 UTC (History)
5 users (show)

See Also:
Latest Commit:
Version Fixed/Implemented In:
Sentry Crash Report:


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Description Sylens 2025-08-23 21:55:53 UTC
SUMMARY
When I try to switch user, my screen becomes black, and only the mouse cursor is visible, but doesnt move, system is unresponsive, not even going to tty via ctrl + alt + f1,2,3,4 etc works. Only hard reset works, by pressing the power button, which is destructive for the disks and my datas!

STEPS TO REPRODUCE
1. Press on start menu
2. select switch user
3. observe the freeze / crash

OBSERVED RESULT
system frozen

EXPECTED RESULT
it shouldn't freeze the system...

SOFTWARE/OS VERSIONS
Operating System: Fedora Linux 42
KDE Plasma Version: 6.4.4
KDE Frameworks Version: 6.17.0
Qt Version: 6.9.1
Kernel Version: 6.15.10-200.fc42.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 4 × Intel® Core™ i5-6500 CPU @ 3.20GHz
Memory: 16 GiB of RAM (15.6 GiB usable)
Graphics Processor: NVIDIA GeForce GTX 1050 Ti
Manufacturer: MSI
Product Name: MS-7972
System Version: 2.0
Comment 1 TraceyC 2025-08-25 19:44:51 UTC
Thanks for the bug report. Since the screen goes black, it sounds like either plasmashell or kwin may have been what crashed.

As the message at the top of the summary says, if something crashed, we need a backtrace of it so we can figure out what's going on. Can you please attach a backtrace of the crash using the coredumpctl command-line program, as detailed in https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports#Retrieving_a_backtrace_using_coredumpctl ?
Comment 2 Sylens 2025-08-25 20:24:35 UTC
(In reply to TraceyC from comment #1)
> Thanks for the bug report. Since the screen goes black, it sounds like
> either plasmashell or kwin may have been what crashed.
> 
> As the message at the top of the summary says, if something crashed, we need
> a backtrace of it so we can figure out what's going on. Can you please
> attach a backtrace of the crash using the coredumpctl command-line program,
> as detailed in
> https://community.kde.org/Guidelines_and_HOWTOs/Debugging/
> How_to_create_useful_crash_reports#Retrieving_a_backtrace_using_coredumpctl ?

yeah the problem is, that I just made it crash again, and I don't get any coredump - at all :/ not sure how is a bug fixable without a coredump, but this is so odd, that not even a trace is left by this, that its beyond me.
Comment 3 TraceyC 2025-08-26 18:12:12 UTC
(In reply to Sylens from comment #2)
> yeah the problem is, that I just made it crash again, and I don't get any
> coredump - at all :/ not sure how is a bug fixable without a coredump, but
> this is so odd, that not even a trace is left by this, that its beyond me.

Thanks for trying. Things may not be crashing, but freezing.

Can you check kwin's logs when the hard freeze occurs? 

  journalctl --boot --user-unit plasma-kwin_wayland > ~/log.txt

Also, is there any chance that you could retrieve kwin's backtrace when the
hard freeze occurs? You would need to ssh from another computer and attach a debugger to kwin process, e.g.

  sudo gdb -p $(pidof kwin_wayland)

then type

  bt

and paste the output here. Thanks.
Comment 4 Bug Janitor Service 2025-09-10 03:48:25 UTC
🐛🧹 ⚠️ This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information, then set the bug status to REPORTED. If there is no change for at least 30 days, it will be automatically closed as RESOLVED WORKSFORME.

For more information about our bug triaging procedures, please read https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging.

Thank you for helping us make KDE software even better for everyone!
Comment 5 Sylens 2025-09-10 08:41:07 UTC
(In reply to TraceyC from comment #3)
> (In reply to Sylens from comment #2)
> > yeah the problem is, that I just made it crash again, and I don't get any
> > coredump - at all :/ not sure how is a bug fixable without a coredump, but
> > this is so odd, that not even a trace is left by this, that its beyond me.
> 
> Thanks for trying. Things may not be crashing, but freezing.
> 
> Can you check kwin's logs when the hard freeze occurs? 
> 
>   journalctl --boot --user-unit plasma-kwin_wayland > ~/log.txt
> 
> Also, is there any chance that you could retrieve kwin's backtrace when the
> hard freeze occurs? You would need to ssh from another computer and attach a
> debugger to kwin process, e.g.
> 
>   sudo gdb -p $(pidof kwin_wayland)
> 
> then type
> 
>   bt
> 
> and paste the output here. Thanks.

unfortunately none of those commands worked, it couldn't find any backtraces
Comment 6 TraceyC 2025-09-16 21:47:19 UTC
Please run this

journalctl --boot --user-unit plasma-kwin_wayland > ~/log.txt

And then attach ~/log.txt to this report. Thanks.
Comment 7 Bug Janitor Service 2025-10-01 03:46:34 UTC
🐛🧹 ⚠️ This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information, then set the bug status to REPORTED. If there is no change for at least 30 days, it will be automatically closed as RESOLVED WORKSFORME.

For more information about our bug triaging procedures, please read https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging.

Thank you for helping us make KDE software even better for everyone!
Comment 8 Bug Janitor Service 2025-10-16 03:47:15 UTC
🐛🧹 This bug has been in NEEDSINFO status with no change for at least 30 days. Closing as RESOLVED WORKSFORME.