On Wed, May 25, 2022 at 05:03:40PM -0700, Martin KaFai Lau wrote:

quoted

But the problem with going link-only is that I'd have to teach bpftool
to use links for BPF_LSM_CGROUP and it brings a bunch of problems:
* I'd have to pin those links somewhere to make them stick around
* Those pin paths essentially become an API now because "detach" now
  depends on them?
* (right now it automatically works with the legacy apis without any
changes)

It is already the current API for all links (tracing, cgroup...).  It goes
away (detach) with the process unless it is pinned.  but yeah, it will
be a new exception in the "bpftool cgroup" subcommand only for
BPF_LSM_CGROUP.

If it is an issue with your use case, may be going back to v6 that extends
the query bpf_attr with attach_btf_id and support both attach API ?

[ hit sent too early... ]
or extending the bpf_prog_info as you also mentioned in the earlier reply.
It seems all have their ups and downs.