Re: [PATCHv5 bpf-next 18/28] libbpf: Add bpf_link_create support for tracing_multi link

[sashiko-bot@kernel.org]

Sashiko AI review found 1 potential issue(s):
- [Low] The patch relies on UAPI identifiers (`BPF_TRACE_FENTRY_MULTI`, `BPF_TRACE_FEXIT_MULTI`, `BPF_TRACE_FSESSION_MULTI` and `attr.link_create.tracing_multi`) that are missing from the kernel's UAPI headers.
--

commit c0f93aeff516311471202b8e10f7e659acca62b7
Author: Jiri Olsa <jolsa@kernel.org>

libbpf: Add bpf_link_create support for tracing_multi link

This commit adds bpf_link_create support for the tracing_multi link,
introducing a new tracing_multi record in struct bpf_link_create_opts.

> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
> index 5846de3642090..ad4c94b6758d3 100644
> --- a/tools/lib/bpf/bpf.c
> +++ b/tools/lib/bpf/bpf.c
> @@ -790,6 +790,15 @@ int bpf_link_create(int prog_fd, int target_fd,
>  		if (!OPTS_ZEROED(opts, uprobe_multi))
>  			return libbpf_err(-EINVAL);
>  		break;
> +	case BPF_TRACE_FENTRY_MULTI:
> +	case BPF_TRACE_FEXIT_MULTI:
> +	case BPF_TRACE_FSESSION_MULTI:
> +		attr.link_create.tracing_multi.ids = ptr_to_u64(OPTS_GET(opts, tracing_multi.ids, 0));

Are BPF_TRACE_FENTRY_MULTI, BPF_TRACE_FEXIT_MULTI, BPF_TRACE_FSESSION_MULTI,
and attr.link_create.tracing_multi defined in the kernel's UAPI headers?

It looks like these enum variants and the tracing_multi structure within the
link_create union of union bpf_attr are missing from include/uapi/linux/bpf.h
and tools/include/uapi/linux/bpf.h. Attempting to use these undeclared
identifiers breaks compilation. Is there a missing patch in this series that
updates the UAPI headers?

> +		attr.link_create.tracing_multi.cookies = ptr_to_u64(OPTS_GET(opts, tracing_multi.cookies, 0));
> +		attr.link_create.tracing_multi.cnt = OPTS_GET(opts, tracing_multi.cnt, 0);
> +		if (!OPTS_ZEROED(opts, tracing_multi))
> +			return libbpf_err(-EINVAL);
> +		break;
>  	case BPF_TRACE_RAW_TP:

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260417192502.194548-19-jolsa@kernel.org?part=1