Re: linux-next: PowerPC WARN_ON_ONCE() after merge of the finaltree (tip related)

[Peter Zijlstra]

On Thu, 2010-04-15 at 19:15 +0200, Frederic Weisbecker wrote:
> > that looks rather ugly. Why not do a raw:
> > 
> >       this_cpu_inc(lockdep_stats.redundant_hardirqs_on);
> > 
> > which basically open-codes debug_atomic_inc(), but without the warning?
> 
> 
> Because that would open a race against interrupts that might
> touch lockdep_stats.redundant_hardirqs_on too.


How so, its a pure per-cpu variable right? so either the increment
happens before the interrupts hits, or after, in either case there
should not be a race with interrupts.
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