It was found that when a cgroup2 filesystem was mounted, control files other than the base cgroup.* ones were not shown in the root directory. They were shown only after some controllers were activated in the root's cgroup.subtree_control file.
This was caused by a lack of the kernfs_activate() call which was fixed by this patch. Signed-off-by: Waiman Long <[email protected]> --- kernel/cgroup/cgroup.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 89a23c6..fb1893b 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -2024,8 +2024,10 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, dentry = cgroup_do_mount(&cgroup2_fs_type, flags, &cgrp_dfl_root, CGROUP2_SUPER_MAGIC, ns); - if (!IS_ERR(dentry)) + if (!IS_ERR(dentry)) { apply_cgroup_root_flags(root_flags); + kernfs_activate(cgrp_dfl_root.cgrp.kn); + } } else { dentry = cgroup1_mount(&cgroup_fs_type, flags, data, CGROUP_SUPER_MAGIC, ns); -- 1.8.3.1
