Re: [PATCH 4/4] cgroup/bpf: Honor cgroup NS in cgroup_iter for ancestors

[Hao Luo]

On Mon, Aug 29, 2022 at 10:49 AM Tejun Heo <tj@xxxxxxxxxx> wrote:
>
> On Mon, Aug 29, 2022 at 10:30:45AM -0700, Yosry Ahmed wrote:
> > > I'd like to clarify, if a process A in a broad cgroup ns sets up a BPF
> > > cgroup iterator, exposes it via bpffs and than a process B in a narrowed
> > > cgroup ns (which excludes the origin cgroup) wants to traverse the
> > > iterator, should it fail straight ahead (regardless of iter order)?
> > > The alternative would be to allow self-dereference but prohibit any
> > > iterator moves (regardless of order).
> > >
> >
> > imo it should fail straight ahead, but maybe others (Tejun? Hao?) have
> > other opinions here.
>
> Yeah, I'd prefer it to fail right away as that's simple and gives us the
> most choices for the future.
>

Thanks Michal for fixing the cgroup iter use case! I agree that
failing straight ahead is better. I don't envision a use case that
wants the alternative.

> Thanks.
>
> --
> tejun