On Thu, Jun 29, 2023 at 08:11:33AM -0400, Waiman Long [off-list ref] wrote:

So I think you should just use
cgroup_subsys_on_dfl(cpuset_cgrp_subsys) as the v2 check if your focus
is just to prevent problem when enabling cpuset controller.

I thought the bare cgroup_subsys_on_dfl(cpuset_cgrp_subsys) is not used
in cpuset.c but I was wrong -- yes, I'll change this.

This change will likely conflict with the latest cpuset change on tracking #
of dl tasks in a cpuset. You will have to, at least, move the dl task check
before the security_task_setscheduler() check.

Another fact about cpuset controller enabling is that both cpus_allowed and
mems_allowed are empty at that point. You may also add these checks as a
preconditions for disabling the security_task_setscheduler check.

Ah, I will rebase on fresh mainline (or do you mean another reference?).

Thanks for the hints,
Michal