Patch https://lists.freedesktop.org/archives/dri-devel/2018-September/188256.html breaks ARC++.

Some analysis from marcheu and tfiga:


Stéphane writes
--
As Emil pointed out in the thread, it will at least break our sandbox
and probably also the ARC++ selinux stuff. Chrome finds the drm
devices itself through /sys/class/drm so that should be fine. I also
wonder if it will break on antique kernels, but nothing that would
affect us.



Tomasz writes:
--
Yeah, that would indeed break ARC++, because /sys/dev/char/226:*
entries have default sysfs selinux labels (u:object_r:sysfs:s0).

We already have code that sets the labels for render node entries
under /sys/class/drm [1], so it wouldn't be that difficult to do the
same for match entries in /sys/dev/char/, though.

[1] https://cs.corp.google.com/chromeos_public/src/platform2/arc/setup/arc_setup.cc?rcl=ce087c3b1fa4c31e18202e9a17c18bd3712de8d3&l=1386