Bug 497903

Summary:	plasmashell locks up with 100% CPU after adding widgets to panel with Audio Volume widget or Battery and Brightness widget on it
Product:	[Plasma] plasmashell	Reporter:	Richard Day <r.day80>
Component:	Panel	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED DUPLICATE
Severity:	crash	CC:	isma.af, john.kizer, nate, niccolo.venerandi
Priority:	NOR
Version First Reported In:	6.2.4
Target Milestone:	1.0
Platform:	Manjaro
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	Tarball of .config directory

Description Richard Day 2024-12-26 12:48:13 UTC

SUMMARY

After adding an instance of the Audio Volume widget or the Battery and Brightness to a panel, adding further widgets to that panel cause plasmashell to lock up and run at 100% CPU until killed. Other widgets may cause the same issue. 

STEPS TO REPRODUCE
1. Create a new empty panel (location does not matter, set Width/Height to 'Fit Content', Visibility to 'Dodge Windows')
2. Add an Audio Volume or Battery and Brightness widget to the panel 
3. (note system is still functional)
4. Add any other widget (e.g. Digital Clock) to the same panel
5. Plasma UI locks-up, can still Alt-Tab to applications but panel editing is frozen
6. Running 'killall -9 plasmashell' recovers system but latest edits are lost

OBSERVED RESULT
1. Plasmashell locks up, no further editing of panel configuration is allowed
2. Alt-tab can still be used to switch applications (which still function)
3. Ctrl-Alt-F3 can be used to switch to a text-only console which can be used to kill plasmashell to recover the system

EXPECTED RESULT
The second widget should be added to the panel and editing is allowed to continue.

SOFTWARE/OS VERSIONS
Operating System: Manjaro Linux 
KDE Plasma Version: 6.2.4
KDE Frameworks Version: 6.8.0
Qt Version: 6.8.1
Kernel Version: 6.12.4-1-MANJARO (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i7-8665U CPU @ 1.90GHz
Memory: 15.4 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics 620

ADDITIONAL INFORMATION

Comment 1 John Kizer 2025-01-02 20:18:15 UTC

Hi - thanks for the well-detailed bug report! I followed those steps but didn't end up with plasmashell freezing. Just to double-check, does this issue continue to happen with the latest KDE Frameworks (6.9.0) installed as well?

Comment 2 Richard Day 2025-01-02 21:08:48 UTC

Created attachment 177059 [details]
Tarball of .config directory

Attached is a tarball of the .config directory of a new user (named 'richardtest') with a panel configuration that, once an additional widget is added to the panel at the top of the screen, should trigger the bug.

Comment 3 Richard Day 2025-01-02 21:13:24 UTC

Hi, I'd be happy to try it with KDE Frameworks version 6.9.0 if you can provide some guidance on how to install it on Manjaro, I have an up to date Manjaro system but it only includes version 6.8.0.

In the meantime, I created a new user and followed the instructions to trigger the bug - just to ensure it wasn't anything to do with my existing user profile. And it did indeed trigger the bug again.

So I've attached a tarball of the .config directory of that user with the panel configuration that might help you re-create the bug.

Comment 4 John Kizer 2025-01-03 17:13:36 UTC

I'm not a Manjaro user myself, so I'm not sure of all the ins and outs, but my understanding is that their "unstable" repositories are effectively equivalent to the source Arch repositories. It might be possible to selectively use those, but I can't speak to how safe that is, so I wouldn't want to encourage something that risks causing major issues on your primary machine :-)

Just noting on this comment for future investigation, that I wonder if this is somehow related to https://bugs.kde.org/show_bug.cgi?id=491946 , only because it seems like "determining the width of panel components" is possibly relevant to both?

Comment 5 Nate Graham 2025-01-04 05:01:48 UTC

Very likely caused by the same issue that caused Bug 489086, which is fixed in Plasma 6.3.

*** This bug has been marked as a duplicate of bug 489086 ***