Re: [PATCH bpf-next v6 1/2] bpf: Support pointer param types via SCALAR_VALUE for trampolines

Eduard Zingerman
2026-03-24T20:21:34Z

On Sat, 2026-03-14 at 19:21 +1100, Slava Imameev wrote:
> Add BPF verifier support for single- and multi-level pointer
> parameters and return values in BPF trampolines by treating these
> parameters as SCALAR_VALUE.
>
> This extends the existing support for int and void pointers that are
> already treated as SCALAR_VALUE.
>
> This provides consistent logic for single and multi-level pointers:
> if a type is treated as SCALAR for a single-level pointer, the same
> applies to multi-level pointers. The exception is pointer-to-struct,
> which is currently PTR_TO_BTF_ID for single-level but treated as
> scalar for multi-level pointers since the verifier lacks context
> to infer the size of target memory regions.
>
> Safety is ensured by existing BTF verification, which rejects invalid
> pointer types at the BTF verification stage.
>
> Signed-off-by: Slava Imameev <slava.imameev@crowdstrike.com>
> ---

Acked-by: Eduard Zingerman <eddyz87@gmail.com> …