On Mon, May 04, 2020 at 02:38:18PM +0300, Vasily Averin wrote:
> >>From 933db73351d359f74b14f4af095808260aff11f9 Mon Sep 17 00:00:00 2001
> From: Vasily Averin <vvs@xxxxxxxxxxxxx>
> Date: Wed, 29 Apr 2020 12:01:24 +0300
> Subject: drm/qxl: qxl_release use after free
>
> From: Vasily Averin <vvs@xxxxxxxxxxxxx>
>
> commit 933db73351d359f74b14f4af095808260aff11f9 upstream.
> qxl_release should not be accesses after qxl_push_*_ring_release() calls:
> userspace driver can process submitted command quickly, move qxl_release
> into release_ring, generate interrupt and trigger garbage collector.
>
> It can lead to crashes in qxl driver or trigger memory corruption
> in some kmalloc-192 slab object
>
> Gerd Hoffmann proposes to swap the qxl_release_fence_buffer_objects() +
> qxl_push_{cursor,command}_ring_release() calls to close that race window.
>
> cc: stable@xxxxxxxxxxxxxxx
> Fixes: f64122c1f6ad ("drm: add new QXL driver. (v1.4)")
> Signed-off-by: Vasily Averin <vvs@xxxxxxxxxxxxx>
> Link: http://patchwork.freedesktop.org/patch/msgid/fa17b338-66ae-f299-68fe-8d32419d9071@xxxxxxxxxxxxx
> Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
>
> backported to v4.14-stable
Now replaced, thanks.
greg k-h
