The function cgroupstats_build extracts cgroup from the kernfs_node's priv pointer which is a RCU pointer. So, there is no need to grab cgroup_mutex. Just get the reference on the cgroup before using and remove the cgroup_mutex altogether. Signed-off-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: Tejun Heo <tj@kernel.org>