Re: [PATCH] cpufreq: Fix NULL reference crash while accessing policy->governor_data

From: Juri Lelli
Date: Wed Jan 27 2016 - 05:21:56 EST


On 26/01/16 23:49, Rafael J. Wysocki wrote:
> On Tuesday, January 26, 2016 06:01:19 PM Juri Lelli wrote:
> > On 26/01/16 09:57, Juri Lelli wrote:
> > > Hi Viresh,
> > >
> > > On 25/01/16 22:33, Viresh Kumar wrote:
> > > > There is a little race discovered by Juri, where we are able to:
> > > > - create and read a sysfs file before policy->governor_data is being set
> > > > to a non NULL value.
> > > > OR
> > > > - set policy->governor_data to NULL, and reading a file before being
> > > > destroyed.
> > > >
>
> [cut]
>
> >
> > So, this goes away with your patch (that I forward ported) and a small
> > additional fix on top of that.
>
> Which patch exactly is that?
>

As Viresh said, this is:

cpufreq: Access governor's sysfs attributes without 'policy->rwsem'
http://www.linux-arm.org/git?p=linux-jl.git;a=commit;h=d3eb02ed23732de2c8671377316a190c38b8fe93

Apologies for the confusion; I was already talking with Viresh on IRC
about it.

Best,

- Juri