Re: [PATCH bpf-next v5 5/8] libbpf: Version bpf_program__set_autoattach() ABI change

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] libbpf: API/ABI pollution with internal symbol versioning aliases
--

commit d36af029b0efcdd76647414b7d862ed1b5af5ff2
Author: Andrey Grodzovsky <andrey.grodzovsky@crowdstrike.com>

libbpf: Version bpf_program__set_autoattach() ABI change

This commit splits bpf_program__set_autoattach() via ELF symbol versioning to
change its return type from void to int. It introduces
bpf_program__set_autoattach_deprecated for the original behavior and
bpf_program__set_autoattach_v1_8_0 for the new behavior.

> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> index faea42f758479..d172c137cc376 100644
> --- a/tools/lib/bpf/libbpf.h
> +++ b/tools/lib/bpf/libbpf.h
[ ... ]
> @@ -393,6 +393,12 @@ LIBBPF_API bool bpf_program__autoload(const struct bpf_program *prog);
>  LIBBPF_API int bpf_program__set_autoload(struct bpf_program *prog, bool autoload);
>  LIBBPF_API bool bpf_program__autoattach(const struct bpf_program *prog);
>  LIBBPF_API int bpf_program__set_autoattach(struct bpf_program *prog, bool autoattach);
> +/* this "specialization" should go away once the deprecation window for
> + * bpf_program__set_autoattach_deprecated() closes
> + */
> +LIBBPF_API int bpf_program__set_autoattach_v1_8_0(struct bpf_program *prog, bool autoattach);
> +LIBBPF_DEPRECATED_SINCE(1, 8, "use int-returning bpf_program__set_autoattach() instead")
> +LIBBPF_API void bpf_program__set_autoattach_deprecated(struct bpf_program *prog, bool autoattach);

[Severity: High]
Does exposing these internal versioning aliases in the public header pollute
the public API?

Since bpf_program__set_autoattach_v1_8_0 is not in the export map, won't any
direct calls to it by users cause linker errors?

> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
> index 8def5474885a8..999e791d98870 100644
> --- a/tools/lib/bpf/libbpf.map
> +++ b/tools/lib/bpf/libbpf.map
[ ... ]
> @@ -465,6 +465,8 @@ LIBBPF_1.8.0 {
>  		bpf_program__clone;
>  		bpf_program__load;
>  		bpf_program__load_strategy;
> +		bpf_program__set_autoattach;
> +		bpf_program__set_autoattach_deprecated;

[Severity: High]
Is it intended to export bpf_program__set_autoattach_deprecated in the
LIBBPF_1.8.0 ABI node?

This seems to make it a newly added, globally-visible ABI symbol instead of
an internal symver target, which permanently pollutes the libbpf.so stable
ABI.

>  		bpf_program__set_load_strategy;
>  		btf__find_by_name_kind_own;
>  		btf__new_empty_opts;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260923232939.1886328-1-andrey.grodzovsky@crowdstrike.com?part=5