This might be related to Fan working non-stop
Yesterday, twice, the fan went nuts, top showed virtually no activity, load was about .09. Then just before quitting, top showed CPU0 at virtually 100% in red, kernel, but other user space was near zero and the process tree showed no activity. I shut down all of my desktop activity and just before shutting down, this was what top looked like. Load average of 0.68 with processes sorted by CPU.
Are there ps flags to see kernel activity? How else might I research this?
This morning I repeated the same application test that failed and did not see the same issue - as a test. I did not log out and back on to see if something was related to the Gnome desktop environment. Nor, did I run iotop, but the disk light showed no activity.