Please apply the following patch to stable 4.4. Seems we can hit this on CDV without an evil userspace. Fixes a warning and a race.

commit d3e376f52d095103ca51dbda4d6ff8aaf488f98f Author: Daniel Vetter daniel.vetter@ffwll.ch Date: Mon Nov 23 10:32:49 2015 +0100

drm/gma500: Use correct unref in the gem bo create function

This is called without dev->struct_mutex held, we need to use the _unlocked variant.

Never caught in the wild since you'd need an evil userspace which races a gem_close ioctl call with the in-progress open.

Cc: Patrik Jakobsson patrik.r.jakobsson@gmail.com Acked-by: Patrik Jakobsson patrik.r.jakobsson@gmail.com Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch Link: http://patchwork.freedesktop.org/patch/msgid/1448271183-20523-17-git-send-em...

Cc: stable@vger.kernel.org # v4.4 Tested-by: David John Summers