On Thu, Jan 14, 2021 at 10:08:19PM +0800, chenzhou [off-list ref] wrote:

In this case, at the beginning of function check_cgroupfs_options(), the mask
ctx->subsys_mask will be 0. And if we mount without 'none' and 'name=' options,
then in check_cgroupfs_options(), the flag ctx->all_ss will be set, that is, select all the subsystems.

But even then, the line
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/kernel/cgroup/cgroup-v1.c?h=v5.11-rc3#n1012
would select only 'enabled' controllers, wouldn't it?

It's possible I missed something but if this means that cgroup_no_v1=
doesn't hold to its expectations, I'd suggest adding proper Fixes: tag
to the patch.

Thanks,
Michal