Date: Tue, 30 May 2006 12:54:47 -0700
From: Andrew Morton <akpm@osdl.org>
To: Andi Kleen <ak@suse.de>
Cc: mingo@elte.hu, linux-kernel@vger.kernel.org
Subject: Re: [patch, -rc5-mm1] lock validator: disable NMI watchdog if
 CONFIG_LOCKDEP, i386
Message-Id: <20060530125447.b646d2dd.akpm@osdl.org>
In-Reply-To: <p73mzcz1g0h.fsf@verdi.suse.de>
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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.
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