Re: Preemption Broken: centrino_target busted under SMP on 2.6.20.4

From: Dave Jones
Date: Tue Apr 10 2007 - 00:30:33 EST


On Mon, Apr 09, 2007 at 08:51:36PM -0700, Andrew Morton wrote:
> On Mon, 9 Apr 2007 23:08:23 -0400 Dave Jones <davej@xxxxxxxxxx> wrote:
>
> > > This whole file is going away in .22, and we have a viable alternative in
> > > .21 (acpi-cpufreq), so I'm not overly worried about fixing this up
> > > given it only shows up in debug kernels, especially at this stage in -rc.
> > >
> > > (Yeah, it's a cop-out, but unless someone with more interest in this problem
> > > steps up, I've bigger fishes to fry).
> >
> > One last try...
> > (I didn't think too long about this, so this might be equally busted,
> > but if so, see comment above).
>
> Yes, I expect that should squish the warnings. It looks all racy wrt cpu hotplug
> and against async set_cpus_allowed(), but if those are our worst problems, we're
> good.

It probably needs a couple more preempt_enable()'s sprinkled throughout the function
to take care of the break's. I also missed a goto case.
Meh, this cure is as bad as the disease.

Dave

--
http://www.codemonkey.org.uk
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