Re: [RFC bpf-next 4/4] selftests/bpf: Add attach bench test

[Andrii Nakryiko]

On Wed, Apr 13, 2022 at 9:44 AM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
> On Tue, 12 Apr 2022 09:49:23 +0900
> Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:
>
> > > I'm really curious how did you manage to attach to everything in
> > > available_filter_functions because when I'm trying to do that I fail.
> > > available_filter_functions has a bunch of functions that should not be
> > > attachable (e.g., notrace functions). Look just at __bpf_tramp_exit:
> > >
> > >   void notrace __bpf_tramp_exit(struct bpf_tramp_image *tr);
>
> Did you only use the "notrace" on the prototype? I see the semicolon at
> the end of your comment. It only affects the actual function itself,
> not the prototype.

notrace is both on declaration and on definition, see kernel/bpf/trampoline.c:

void notrace __bpf_tramp_exit(struct bpf_tramp_image *tr)
{
        percpu_ref_put(&tr->pcref);
}


>
> -- Steve