Re: [PATCH 6.6.y] bpf: Check the helper function is valid in get_helper_proto

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] bpf: multi-line comment style violation in bpf_tail_call_proto
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commit f05c559892f9e9f36efa93c44d19d9d526404f49
Author: Jiri Olsa <olsajiri@gmail.com>

bpf: Check the helper function is valid in get_helper_proto

This commit adds a check in check_helper_call() to ensure the helper function
pointer is not NULL, preventing a verifier bug when config options are disabled.
It also sets the unused tail_call helper function to BPF_PTR_POISON.

Link: https://lore.kernel.org/bpf/20250814200655.945632-1-jolsa@kernel.org

> diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
> index 9fa984ee076bc..bec8876f12375 100644
> --- a/kernel/bpf/core.c
> +++ b/kernel/bpf/core.c
> @@ -2959,7 +2959,10 @@ EXPORT_SYMBOL_GPL(bpf_event_output);
>  
>  /* Always built-in helper functions. */
>  const struct bpf_func_proto bpf_tail_call_proto = {
> -	.func		= NULL,
> +	/* func is unused for tail_call, we set it to pass the
> +	 * get_func_proto check
> +	 */

[Severity: Low]
This isn't a bug, but does this multi-line comment follow the BPF subsystem's
formatting rules? It seems the opening /* should be on its own line, with the
comment text starting on the next line.

> +	.func		= BPF_PTR_POISON,
>  	.gpl_only	= false,
>  	.ret_type	= RET_VOID,
>  	.arg1_type	= ARG_PTR_TO_CTX,

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Sashiko AI review · https://sashiko.dev/#/patchset/20261016022203.17034-1-artem@trailofbits.com?part=1