Re: [BUG] cpu hotplug vs scheduler

Avi Kivity
2008-05-13T15:33:19Z

Avi Kivity wrote:
> I'm testing host cpu hotplug with kvm. Basically running 7 guests on
> a 4 core machine, offlining and onlining host cpus at random.
> Eventually I hit this:
>

[snip oops]

> This seems to be the assignment to cfs_rq after pick_next_entity().
>
> I'm running kvm.git, which is currently 2.6.26-rc2 plus a few kvm
> patches. It could be kvm's fault, but it doesn't appear so from the
> traces.
>

I get the same oops running with the kvm modules unloaded. None of
kvm.git's changes are in core code, so this is definitely a mainline
problem.

It took about 40 minutes to reproduce; 1200 cpus onlined and 1200 cpus
offlined.