On Jun 19, 2025, at 1:48 AM, Christian Brauner [off-list ref] wrote:

On Wed, Jun 18, 2025 at 02:43:34PM -1000, Tejun Heo wrote:

quoted

Hello,

On Wed, Jun 18, 2025 at 04:37:35PM -0700, Song Liu wrote:

quoted

Introduce a new kfunc bpf_kernfs_read_xattr, which can read xattr from
kernfs nodes (cgroupfs, for example). The primary users are LSMs, for
example, from systemd. sched_ext could also use xattrs on cgroupfs nodes.
However, this is not allowed yet, because bpf_kernfs_read_xattr is only
allowed from LSM hooks. The plan is to address sched_ext later (or in a
later revision of this set).

I don't think kernfs is the name we should be exposing to BPF users. This is
an implementation detail which may change in the future. I'd rather make it
a generic interface or a cgroup specific one. The name "kernfs" doesn't

cgroup specific, please. That's what I suggested to Daan.

I guess there was some misunderstanding. I will make this cgroup specific 
in v2. 

Thanks,
Song