[Intel-gfx] [PATCH v2 1/2] drm/i915: fix possible refcount leak when resetting forcewake

[Imre Deak]

On Fri, 2014-06-06 at 19:46 +0200, Daniel Vetter wrote:
> On Fri, Jun 06, 2014 at 12:08:43PM +0100, Chris Wilson wrote:
> > On Fri, Jun 06, 2014 at 02:04:37PM +0300, Imre Deak wrote:
> > > If the timer putting the last forcewake refcount was pending and we
> > > canceled it, we'll leak the corresponding forcewake and RPM references.
> > > 
> > > v2:
> > > - do the ptr casting at the caller instead of adding a separate helper
> > >   for this (Chris)
> > > 
> > > Signed-off-by: Imre Deak <imre.deak at intel.com>
> > Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
> 
> Both patches merged to dinq (Chris clarified on irc that his r-b is for
> both).
>
> Since this only blows up in a super-contrived testcase I don't
> think this is material for -fixes.

Note that the issue fixed by 1/2 could also happen normally, though the
window for race is small. One scenario would be runtime resume
->deferred rps_enable followed directly by system suspend or gpu reset.

--Imre