SUMMARY kquickcharts uses 100% cpu from plasmashell, making it unresponsive STEPS TO REPRODUCE 1. Start KDE from xinit via startplasma-x11 OBSERVED RESULT This happened after my daily upgrade routine, where kquickcharts was upgraded to 5.82.0 (along with most KDE packages). Task manager is unresponsive: can't open application launcher, the clock is stuck, started applications have no entries. The wifi connected notification is also stuck and it cannot be closed. The task manager cannot be interacted with at all (left/right clicks have no effect on it). Running htop shows that plasmashell uses 100% of a single CPU core. Running perf top shows that the CPU is busy with something from libQuickCharts.so. At first I thoght that this is related to the system monitor sensor widget I use, but after removing it from the task manager the issue is still present. Downgrading kquickcharts to version 5.81.0-1 fixes the issue, hence my guess that this is a kquickcharts problem. EXPECTED RESULT plasmashell should work fine. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Arch Linux latest (as of 2021-05-09) KDE Plasma Version: 5.21.5 KDE Frameworks Version: 5.82.0 Qt Version: 5.12.2 (+kde+r192-1) ADDITIONAL INFORMATION This is an x11 plasma session running on an i7-8665U iGPU.
I have 3 similar machines: - they all run Arch Linux + KDE - software versions should be the same, I update them several times a week - mostly the same KDE related settings Weird thing is that this issue seems to affect only one of them: A Dell Latitude laptop with the mentioned i7-8665U CPU/GPU, no dedicated graphics. I have to keep kquickcharts downgraded to 5.81.0-1 on this machine to avoid the issue. The rest are not affected: - desktop PC with a dedicated nvidia gpu (proprietary driver, has no iGPU) - older Macbook air (i7-4650U CPU/GPU, no dedicated graphics) These work fine with kquickcharts 5.82.0-1, I'm writing this comment from the desktop PC. Any tips on how I could gather more information (if required)? I can reproduce the problem relatively easily (I just update kquickcharts and restart plasma on the affected laptop, then roll it back to the older version to fix it).
The issue no longer occours after upgrading to plasma-workspace 5.22.0.
Oh good. :)