Re: [PATCH bpf-next v5 2/5] bpf: tcp: Mark bpf_load_hdr_opt() arg2 as read-write

[Martin KaFai Lau]

On 12/12/24 3:22 PM, Daniel Xu wrote:
> MEM_WRITE attribute is defined as: "Non-presence of MEM_WRITE means that
> MEM is only being read". bpf_load_hdr_opt() both reads and writes from
> its arg2 - void *search_res.
>
> This matters a lot for the next commit where we more precisely track
> stack accesses. Without this annotation, the verifier will make false
> assumptions about the contents of memory written to by helpers and
> possibly prune valid branches.

Acked-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx>