Re: [PATCH bpf-next v4 5/7] 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:
- [Medium] libbpf: internal versioned aliases improperly exposed in public ABI
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commit f4a1074a0b47562f2c3d7f448c920fa57fb2ed38
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. 
It introduces a deprecated variant bound to LIBBPF_1.0.0 and a new variant 
returning int bound to LIBBPF_1.8.0 to handle manual load strategy rejections.

> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> --- 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: Medium]
Does exposing these internal versioned aliases in the public header 
defeat the purpose of transparent ELF versioning?

Building any application against this updated header might expose these 
internal symbols, and dynamic linking could permanently bind them to the 
polluted ABI. 

Additionally, because the deprecation macro is attached to the internal alias 
rather than the standard name, will users ever see the deprecation warning 
naturally when they call bpf_program__set_autoattach()?

[ ... ]

> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
> --- 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: Medium]
Is it intended to export the internal compat implementation as a public 
symbol in the new LIBBPF_1.8.0 namespace?

This appears to permanently leak the internal compatibility symbol into the
public ABI.

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Sashiko AI review · https://sashiko.dev/#/patchset/20260921223937.3203093-1-andrey.grodzovsky@crowdstrike.com?part=5