Re: [PATCH bpf-next 1/3] bpf: Export btf_get_module_btf() and btf_relocate_id()

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] API Asymmetry and Resource Leak due to unexported btf_put()
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commit 51050bef777abcb3d2969804b1e3693feb10a170
Author: Mykyta Yatsenko <yatsenko@meta.com>

bpf: Export btf_get_module_btf() and btf_relocate_id()

This commit makes btf_get_module_btf() and btf_relocate_id() available outside
kernel/bpf/btf.c by exporting them. This allows the tracing core to look up
module BTF and translate split BTF ids.

> diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
> index 77af44d8a3ad3..aa88d18247bda 100644
> --- a/kernel/bpf/btf.c
> +++ b/kernel/bpf/btf.c
[ ... ]
> @@ -8500,7 +8501,7 @@ struct module *btf_try_get_module(const struct btf *btf)
>  /* Returns struct btf corresponding to the struct module.
>   * This function can return NULL or ERR_PTR.
>   */
> -static struct btf *btf_get_module_btf(const struct module *module)
> +struct btf *btf_get_module_btf(const struct module *module)
>  {
[ ... ]
> @@ -8529,6 +8530,7 @@ static struct btf *btf_get_module_btf(const struct module *module)
>  
>  	return btf;
>  }
> +EXPORT_SYMBOL_GPL(btf_get_module_btf);

Because btf_get_module_btf() increments the reference count on the returned
struct btf object using btf_get(), callers are required to release this
reference by calling btf_put().

Since btf_put() is not exported, won't loadable modules using this new API
fail to link or be forced to leak the struct btf reference?

Alternatively, if these functions are only meant for the tracing core, which
is always built-in, are these EXPORT_SYMBOL_GPL declarations necessary?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260515-generic_tracepoint-v1-0-aa619fa94132@meta.com?part=1