Commits
Tejun Heo committed 6e6eab0efdf
cgroup: fix cgroup_write_event_control()
81eeaf0411 ("cgroup: make cftype->[un]register_event() deal with
cgroup_subsys_state inst ead of cgroup") updated the cftype event
methods to take @css (cgroup_subsys_state) instead of @cgroup;
however, it incorrectly used @css passed to
cgroup_write_event_control(), which the dummy_css for the cgroup as
the file is a cgroup core file. This leads to oops on event
registration.
Fix it by using the css matching the event target file. Note that
cgroup_write_event_control() now disallows cgroup core files from
being event sources. This is for simplicity and doesn't matter as
cgroup_event will be moved and made specific to memcg.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>