Re: [PATCHv2 bpf-next 15/23] libbpf: Add support to create tracing multi link

[Jiri Olsa <olsajiri@gmail.com>]

On Wed, Mar 04, 2026 at 11:02:25PM +0000, bot+bpf-ci@kernel.org wrote:
> > The provided <pattern> is used as 'pattern' argument in
> > bpf_program__attach_kprobe_multi_opts function.
> 
> The function referenced here should be
> bpf_program__attach_tracing_multi, not
> bpf_program__attach_kprobe_multi_opts. This was noted in v1
> review.

I'm refering to bpf_program__attach_kprobe_multi_opts intentionaly

> 
> > - bpf_program__attach_kprobe_multi_opts must either have
> >   pattern with module spec or BTF ids from the module
> 
> Same here, should be bpf_program__attach_tracing_multi.

yep, that's typo, thnx

> 
> > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > --- a/tools/lib/bpf/libbpf.c
> > +++ b/tools/lib/bpf/libbpf.c
> 
> [ ... ]
> 
> > +struct bpf_link *
> > +bpf_program__attach_tracing_multi(const struct bpf_program *prog, const char *pattern,
> > +				  const struct bpf_tracing_multi_opts *opts)
> > +{
> > +	LIBBPF_OPTS(bpf_link_create_opts, lopts);
> > +	__u32 *ids, *free_ids = NULL;
> > +	__u64 *cookies;
> > +	int prog_fd, link_fd, err, cnt;
> > +	struct bpf_link *link;
> > +
> > +	cnt = OPTS_GET(opts, cnt, 0);
> > +	ids = OPTS_GET(opts, ids, NULL);
> > +	cookies = OPTS_GET(opts, cookies, NULL);
> 
> Should this function validate opts with OPTS_VALID() before
> calling OPTS_GET()? The comparable
> bpf_program__attach_kprobe_multi_opts() does:
> 
>     if (!OPTS_VALID(opts, bpf_kprobe_multi_opts))
>         return libbpf_err_ptr(-EINVAL);
> 
> Without OPTS_VALID(), a caller passing opts with sz=0 would have
> ids, cookies and cnt silently ignored rather than getting -EINVAL
> back.

yep, should be there, will fix, thnx

jirka