Re: [patch, -rc5-mm1] lock validator: disable NMI watchdog if CONFIG_LOCKDEP, i386

Andrew Morton
2006-05-30T19:50:51Z

On 30 May 2006 21:14:54 +0200
Andi Kleen <ak@suse.de> wrote:

> Ingo Molnar <mingo@elte.hu> writes:
> >
> > The NMI watchdog uses spinlocks (notifier chains, etc.),
> > so it's not lockdep-safe at the moment.
>
> That's totally unsafe even without lockdep and should be fixed
> instead. I guess someone bungled the notifier chain conversion.
> The NMI notifiers need to be lockless.
>

Confused. NMI uses notify_die(), which doesn't take locks?

We'll probably accidentally take locks when actually reporting an NMI
watchdog timeout, but that doesn't seem terribly important.