[Intel-gfx] [PATCH] drm: Release driver tracking before making the object available again

[Joonas Lahtinen]

+ Sean

On Mon, 2017-08-21 at 18:16 +0200, Daniel Vetter wrote:
> On Sat, Aug 19, 2017 at 01:05:58PM +0100, Chris Wilson wrote:
> > This is the same bug as we fixed in commit f6cd7daecff5 ("drm: Release
> > driver references to handle before making it available again"), but now
> > the exposure is via the PRIME lookup tables. If we remove the
> > object/handle from the PRIME lut, then a new request for the same
> > object/fd will generate a new handle, thus for a short window that
> > object is known to userspace by two different handles. Fix this by
> > releasing the driver tracking before PRIME.
> > 
> > Fixes: 0ff926c7d4f0 ("drm/prime: add exported buffers to current fprivs
> > imported buffer list (v2)")
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: David Airlie <airlied at linux.ie>
> > Cc: Daniel Vetter <daniel.vetter at intel.com>
> > Cc: Rob Clark <robdclark at gmail.com>
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Cc: Thierry Reding <treding at nvidia.com>
> > Cc: stable at vger.kernel.org
> 
> Do we have an evil igt for this? I guess since the old one didn't have
> one, this new race is also hard to reproduce ...
> 
> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>

Pushed this to drm-misc-fixes (and drm-misc-next for I am a monkey with
a keyboard), thanks for the patch and review.

Sean, you can blame it on me when/if there is trouble caused by the
patch being in both branches. Hopefully next merge will cause less
headache.

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