Bug 422277 - 100% cpu usage and desktop crash if you plaice a certain combination of plasmoid widgets
Summary: 100% cpu usage and desktop crash if you plaice a certain combination of plasm...
Status: RESOLVED FIXED
Alias: None
Product: kdeplasma-addons
Classification: Plasma
Component: systemloadviewer (show other bugs)
Version: 5.18.5
Platform: Manjaro Linux
: NOR grave
Target Milestone: ---
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-05-31 01:32 UTC by Bruno Guedes
Modified: 2025-03-18 17:03 UTC (History)
4 users (show)

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


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Description Bruno Guedes 2020-05-31 01:32:13 UTC
SUMMARY
This bug happens if you use the grouping plasmoid widget to group the 'system load viwer' plasmoid widget with the 'calculator' plasmoid widget and you restart the computer.

STEPS TO REPRODUCE
1. add the grouping plasmoid widget to the desktop
2. put the system load viwer plasmoid widget inside of it
3. then put the calculator plasmoid widget inside of it as well
4. click the system load viewer tab so that it is the plasmoid widget that is shown when the pc restarts.
5. restart the pc.

OBSERVED RESULT
The entire desktop freezes. You will not be able to invoke the desktop menu by right clicking and all other plasmoids that you might have on your desktop will freeze as well.
This includes the plasma panel and the plasmoids in it.

You will still be able to open konsole using the keyboard shortcut(ctrl + alt + t) and, sometimes, krunner works(not always and when it do, it is glitchy).

When I checked ksysguard 1 of my cpu threads was at 100% and its would not go down with time.

I could revert the freezing by removing the system load viwer plasmoid widget from the grouping widget. Even though it was not a simple task since it would freeze quite quickly and, once it freezes, you cannot remove the widget anymore.


EXPECTED RESULT


SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: manjaro linux
(available in About System)

KDE Plasma Version: 5.18.5 and the git package in the manjaro repos (could reproduce in both)

KDE Frameworks Version: 5.70.0 nd the git package in the manjaro repos (could reproduce in both)

Qt Version: 5.14.2

ADDITIONAL INFORMATION

Sorry if the report is not very clear. English is not my first language and I am writing this late at night(tired). If you need more info I can try to make a video from my cellphone reproducing the bug.
Comment 1 Nate Graham 2020-10-16 02:18:49 UTC
Is this still relevant for the new System Monitor applet?
Comment 2 Bruno Guedes 2020-10-18 15:22:47 UTC
Yes, I am still able to reproduce this bug in kde neon unstable with the new System Monitor applet.

I just recorded a video showing how to reproduce it, I just have to make a little edit to sucure some of my info (like number of digits in my password).

I will try to upload it in some hours.
Comment 3 Bruno Guedes 2020-10-18 19:24:03 UTC
video link: https://drive.google.com/file/d/1FSLMenhm7PmrZv739a2e7PO4cvodDdFr/view?usp=sharing

time stamps:

00:00 |---- 00:50
    showing the computer functioning normally 
00:50 |---- 01:30
    adding the widgets
01:30 |---- 01:50
    configuring the system monitor widgets
01:50 |---- 02:17
    showing that the computer is still functioning normally 
02:17 |---- 02:34
    rebooting
02:34 |---- 03:20
    showing that the computer is frozen
03:20 |---- 04:13
    running "plasmashell --replace"
04:13 |---- 04:40
    rebooting again
04:40 |---- 05:12
    showing that even after rebooting the computer is still frozen
05:12 |---- 05:36
    trying to open krunner and giving up
05:36 |---- 06:02
    rebooting (and krunner decides to appear)
06:02 |---- 06:15
    removing the power cable (for some reason if I remove it the computer takes longer to freeze. So I am able to remove the widget before it freezes.)
06:15 |---- 06:20
    trying to remove the widget and failing (wasn't fast enough)
06:20 |---- 07:18
    this time it froze so hard I had to hard reset
07:18 |---- 07:32
    trying to remove the widget and failing againg
07:32 |---- 08:01
    finally beeing able to remove the widget and everything is back to normal
Comment 4 Bug Janitor Service 2020-11-02 04:33:33 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 Bruno Guedes 2020-11-02 14:40:00 UTC
changing status to reported
Comment 6 Simplissimus 2021-04-17 21:53:24 UTC
Hi.

This is my first report, so I'm not quite sure if I should post my comment as a comment in this bug report or open a new one; but as it has to do with the add-on mentioned, I think so. Sorry if I'm not right.

Well, I too confirm that grouping plasmoid is malfunctioning, in my case, with desktop notes. If you put the grouping plasmoid on the desktop and put into it a desktop note widget, nothing happens, but if you put a second one, then when you restart the desktop or just Plasmashell, the entire desktop freezes and the usage of one of the processor cores goes up to 100%, only the mouse and the keyboard respond.
Restarting Plasma doesn't help because Plasma freezes almost immediately after login so you can do nothing on the desktop. The only solution is to kill Plasmashell from a terminal and delete the entries related to grouping plasmoid in the plasma-org.kde.plasma.desktop-appletsrc file.

Translated with www.DeepL.com/Translator (free version)

Plasma 5.21.4
KDE Frameworks 5.81.0
Qt 5.15.2
Comment 7 TraceyC 2025-03-17 19:42:41 UTC
Thanks for reporting this. I'm sorry we hadn't been able to address the bug yet. Is this still an issue with Plasma 6.3.3 or later? The System Load Viewer widget is no longer shipped with Plasma.

If you still see an issue, it's likely with the Grouping widget, that is about to have a fix for an unrelated issue merged. If you do still see a bug with it, please set this report back to REPORTED. Thanks.
Comment 8 Bruno Guedes 2025-03-17 23:20:00 UTC
(In reply to TraceyC from comment #7)

> If you still see an issue, it's likely with the Grouping widget, that is
> about to have a fix for an unrelated issue merged. If you do still see a bug
> with it, please set this report back to REPORTED. Thanks.

Hi, I am not able to reproduce accurately the issue anymore because I changed my notebook.
It was an old 4 core Intel-I5 machine and now I have a (still old) 8-core AMD Ryzen 5. So I cannot say if this bug might still affect older systems.
I also changed distros from Manjaro to Endeavor.
 
But what I can say is that I am not able to reproduce this bug in my current notebook.
I tried with some combinations of system monitoring widgets and sticky note widgets.
None of the combinations gave me any freeze that I could attribute to the grouping plasmoid widget.
That is note to say that there was note a small freeze when starting the desktop, but this is normal even without the grouping plasmoid widget. 

So, for now, I think this issue is FIXED. Even though I can't say when it was fixed.

Operating System: EndeavourOS 
KDE Plasma Version: 6.3.3
KDE Frameworks Version: 6.12.0
Qt Version: 6.8.2
Kernel Version: 6.12.19-1-lts (64-bit)
Graphics Platform: Wayland
Processors: 8 × AMD Ryzen 5 3500U with Radeon Vega Mobile Gfx
Memory: 17,4 GiB of RAM
Graphics Processor: AMD Radeon Vega 8 Graphics
Manufacturer: LENOVO
Comment 9 TraceyC 2025-03-18 17:03:31 UTC
Thanks for the update. I'm glad to hear things are working for you now!