Re: od_set_powersave_bias: NULL pointer dereference

From: Jacob Shin
Date: Wed Jun 26 2013 - 10:36:12 EST


On Wed, Jun 26, 2013 at 08:02:29PM +0530, Viresh Kumar wrote:
> On 26 June 2013 19:58, Jacob Shin <jacob.shin@xxxxxxx> wrote:
> > On Wed, Jun 26, 2013 at 12:18:27PM +0530, Viresh Kumar wrote:
>
> >> I am not sure if this is enough. What if we had ondemand as the
> >> governor initially, then we changed it to something else. Now also
> >> cur_policy contains a address and isn't zero.
> >
> > Right, so we check below ..
> >
> >>
> >> > cpumask_or(&done, &done, policy->cpus);
> >> > +
> >> > + if (policy->governor != &cpufreq_gov_ondemand)
> >> > + continue;
> >
> > This should catch that case no ?
>
> Policy might be freed and reallocated by then. And so doing
> policy->governor is dangerous.

Hm . any hints on how to check for if ondemand is running on this CPU
or not ? I'm not sure what the best way to handle this is ..

Thanks,

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