29 Apr
2020
29 Apr
'20
11:40 a.m.
On Wed, Apr 29, 2020 at 12:01:24PM +0300, Vasily Averin wrote:
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@vger.kernel.org Fixes: f64122c1f6ad ("drm: add new QXL driver. (v1.4)") Signed-off-by: Vasily Averin vvs@virtuozzo.com
Pushed to drm-misc-fixes.
thanks, Gerd