> On Thu, Dec 07, 2023 at 11:07:38AM +0100, Jiri Olsa wrote:
> > + if (tgt_prog) {
> > + /* Bookkeeping for managing the prog attachment chain. If it's a
> > + * tracing program, bump the level, otherwise carry it on.
> > + */
> > + if (prog->type == BPF_PROG_TYPE_TRACING)
> > + prog->aux->attach_depth = tgt_prog->aux->attach_depth + 1;
> > + else
> > + prog->aux->attach_depth = tgt_prog->aux->attach_depth;
> > + }
>
> I'm not sure why we need to keep the attach_depth for all program types,
> I might be missing something but could we perhaps just use flag related
> just to tracing programs like in patch below
Originally I was trying to make the change somewhat generic, so that the
same approach could be used e.g. for extensions if needed (say, instead
of preventing extending fentry/fexit). But since we reduce the scope
anyway, I agree we can simply use a boolean flag. It still has to be set
for the target prog if it's fentry/fexit and already attached somewhere,
but otherwise would be similar to your proposal. Let me prepare the new
version.
