On Sat, Nov 27, 2021 at 02:59:19PM +0000, Wei Yang wrote:

css_alloc() needs the parent css, while cgroup_css() gets current
cgropu's css. So we are getting the wrong css during
cgroup_init_subsys().

Fortunately, cgrp_dfl_root.cgrp's css is not set yet, so the value we
pass to css_alloc() doesn't harm to the system.

Let's pass NULL directly during init, since we know there is no parent
yet.

Signed-off-by: Wei Yang <redacted>

Applied to cgroup/for-5.17 w/ minor description adjustment.

Thanks.

-- 
tejun