About 2 days ago, i switched to Kubuntu. Everything was fine until I began to have an issue where a random CPU core would max at 100% while practically doing nothing. All the other cores would remain at 0% - 5% while one would be stuck at 100%. I wouldn’t be able to do anything, but managed to use htop to diagnose that iwlwifi would be the culprit. Not knowing how to resolve it, I migrated to KDE Fedora to see if it was just an Ubuntu issue, but today only after a couple hours of usage, the same issue started.
kernel:watchdog: BUG: soft lockup - CPU#1 stuck for 86s! [irq/163-iwlwifi:1278]
I have no idea how to resolve this, and any tips would be appreciated. I do use mullvad, so possibly an issue with my VPN? it does happen without the VPN enabled though.
did you open a console and check which process uses up all CPU? (top is your friend here).
The kernel ring buffer error points to the WiFi card. But eventually a helper program is culprit (reason I mention top).
There was a thread here with the WiFi card mentioning a manual upgrade of the wifi-card firmware. I’d try it.
What @Loell_Framework is suggesting is for us to determine if this is infact, a bug with the recommended kernel or something else.
The fact that you indicated you are using mullvad does mean there is the potential for this to be a contributor.
I’d start with Loell’s suggestion. If it is not happening on the live USB, the next step will be to boot back into your own install, temporarily disable/remove mullvad, test again.
If the issue is also not present there as well, then we now know there isn’t an update issue creating a regression and the issue is most likely something with mullvad.