Re: [PATCH] kernfs: Move faulting copy_user operations outside of the mutex

[Joonas Lahtinen]

On to, 2016-03-31 at 12:49 -0400, Tejun Heo wrote:
> On Thu, Mar 31, 2016 at 11:45:06AM +0100, Chris Wilson wrote:
> > 
> > A fault in a user provided buffer may lead anywhere, and lockdep warns
> > that we have a potential deadlock between the mm->mmap_sem and the
> > kernfs file mutex:
> ...
> > 
> > Reported-by: Ville SyrjÃlà <ville.syrjala@xxxxxxxxxxxxxxx>
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94350
> > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> > Reviewed-by: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
> > Cc: Ville SyrjÃlà <ville.syrjala@xxxxxxxxxxxxxxx>
> > Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
> > Cc: Tejun Heo <tj@xxxxxxxxxx>
> > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > Cc: NeilBrown <neilb@xxxxxxx>
> > Cc: linux-kernel@xxxxxxxxxxxxxxx
> Acked-by: Tejun Heo <tj@xxxxxxxxxx>
> 

Thanks.

I have applied this locally to our repo to be included into our CI
builds.

We will drop the local patch once this waterfalls from upstream to our
drm-intel-nightly repo.

Regards, Joonas
-- 
Joonas Lahtinen
Open Source Technology Center
Intel Corporation