[Intel-gfx] [PATCH] drm/i915: Fix null pointer dereference in ring cleanup code

[Daniel Vetter]

On Fri, Oct 31, 2014 at 04:07:35PM +0000, Chris Wilson wrote:
> On Fri, Oct 31, 2014 at 02:52:40PM +0000, Damien Lespiau wrote:
> > On Fri, Oct 31, 2014 at 12:00:26PM +0000, John.C.Harrison at Intel.com wrote:
> > > From: John Harrison <John.C.Harrison at Intel.com>
> > > 
> > > If a ring failed to initialise for any reason then the error path would try to
> > > clean up all rings including those that had not yet been allocated. The ring
> > > clean up code did a check that the ring was valid before starting its work.
> > > Unfortunately, that was after it had already dereferenced the ring to obtain a
> > > dev_private pointer.
> > > 
> > > Signed-off-by: John Harrison <John.C.Harrison at Intel.com>
> > 
> > This looks good to me.
> 
> Really? These functions(!!!) are only called under controlled conditions...
> I would have been happy to see this follow my suggestion I made to fix
> this bug months ago.

Hm, do you mean to shuffle the ring_initialized checks into callers? Or
something else?

John's patch didn't look offensive really, so merged it for now.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch