5.4 doesn't have commit backported which introduces RCU for cgroup root_list, but has a commit fixing a UAF (and thus a CVE) which depends on it.
Thus, we need to backport the original commits. See thread: https://lore.kernel.org/all/xr93ikus2nd1.fsf@gthelen-cloudtop.c.googlers.com...
This patch series backports the requisite commits to 5.4.y, which are picked up from the above mentioned thread.
Thanks, Siddh
Waiman Long (1): cgroup: Move rcu_head up near the top of cgroup_root
Yafang Shao (1): cgroup: Make operations on the cgroup root_list RCU safe
include/linux/cgroup-defs.h | 7 ++++--- kernel/cgroup/cgroup-internal.h | 3 ++- kernel/cgroup/cgroup.c | 23 ++++++++++++++++------- 3 files changed, 22 insertions(+), 11 deletions(-)