[PATCH] drm/fence: fix memory overwrite when setting out_fence fd

[Gustavo Padovan]

2017-01-13 Chad Versace <chadversary at chromium.org>:

> On Fri 13 Jan 2017, Gustavo Padovan wrote:
> > From: Gustavo Padovan <gustavo.padovan at collabora.com>
> > 
> > Currently if the userspace declares a int variable to store the out_fence
> > fd and pass it to OUT_FENCE_PTR the kernel will overwrite the 32 bits
> > above the int variable on 64 bits systems.
> > 
> > Fix this by making the internal storage of out_fence in the kernel a s32
> > pointer.
> > 
> > Reported-by: Chad Versace <chadversary at chromium.org>
> > Signed-off-by: Gustavo Padovan <gustavo.padovan at collabora.com>
> > Cc: Daniel Vetter <daniel at ffwll.ch>
> > Cc: Rafael Antognolli <rafael.antognolli at intel.com>
> > Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > Cc: stable at vger.kernel.org
> 
> Reviewed-and-Tested-by: Chad Versace <chadversary at chromium.org>
> 
> I applied this to my kernel branch, updated kmscube, and the spinning cube still looks good.
> For reference, here are the tags I tested with:
> 
>     mesa: http://git.kiwitree.net/cgit/~chadv/mesa/tag/?h=chadv/review/i965-exec-fence-v03
>     libdrm: http://git.kiwitree.net/cgit/~chadv/libdrm/tag/?h=chadv/review/intel-exec-fence-v01
>     linux: http://git.kiwitree.net/cgit/~chadv/linux/tag/?h=chadv/test/i915-exec-fence-v04
>     kmscube: http://git.kiwitree.net/cgit/~chadv/kmscube/tag/?h=chadv/test/fences-v03

I pushed this patch to drm-misc-fixes. Thank you all.

Gustavo