Messages in this thread | | | From | Yosry Ahmed <> | Date | Mon, 29 Aug 2022 10:30:45 -0700 | Subject | Re: [PATCH 4/4] cgroup/bpf: Honor cgroup NS in cgroup_iter for ancestors |
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On Mon, Aug 29, 2022 at 6:00 AM Michal Koutný <mkoutny@suse.com> wrote: > > On Fri, Aug 26, 2022 at 10:41:37AM -0700, Yosry Ahmed <yosryahmed@google.com> wrote: > > I understand that currently cgroup_iter is the only user of this, but > > for future use cases, is it safe to assume that cgrp will always be > > inside ns? Would it be safer to do something like: > > I preferred the simpler root_cgrp comparison to avoid pointer > arithmetics in cgroup_is_descendant. But I also made the assumption of > cgrp in ns. > > Thanks, I'll likely adjust cgroup_path_ns to make it more robust for > an external cgrp. >
Great, thanks!
> > 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.
> > Thanks, > Michal
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