I compile a local kernel from the src.rpm, optimized for my hardware.
Twice now since I started running 5.6 I've seen a null dereference
error. I looked in bugzilla and didn't see this, though there were
lots of null dereference bugzillas. The error has only occurred at the
end of a dnf update, after the scriptlets are run. So, it could be an
error in dnf, I suppose.
The strange thing is, it seems to be bfq causing the problem. And it
only hangs one core; after a while, another core sends an nmi to the
guilty core, and my system then becomes responsive for a brief time.
I can switch from the virtual consoles to X, and even move around in X,
but eventually the system hangs, and I have to reset it. I expect that
the mess isn't being cleaned up, and eventually the guilty core is
rescheduled for a task, and bam!
Is this a known issue? Is it worth opening a bugzilla?