Re: [RFC PATCH bpf-next v2 03/11] bpf: Unify dynptr handling in the verifier

[Eduard Zingerman <eddyz87@gmail.com>]

On Fri, 2026-03-06 at 22:44 -0800, Amery Hung wrote:
> Simplify dynptr checking for helper and kfunc by unifying it. Remember
> initialized dynptr in process_dynptr_func() so that we can easily
> retrieve the information for verification later.
> 
> Signed-off-by: Amery Hung <ameryhung@gmail.com>
> ---

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

[...]

> @@ -8825,6 +8821,20 @@ static int process_dynptr_func(struct bpf_verifier_env *env, int regno, int insn
>  		}
>  
>  		err = mark_dynptr_read(env, reg);
> +
> +		if (initialized_dynptr) {
> +			struct bpf_func_state *state = func(env, reg);
> +			int spi;
> +
> +			if (reg->type != CONST_PTR_TO_DYNPTR) {
> +				spi = dynptr_get_spi(env, reg);
> +				reg = &state->stack[spi].spilled_ptr;
> +			}
> +
> +			initialized_dynptr->id = reg->id;
> +			initialized_dynptr->type = reg->dynptr.type;
> +			initialized_dynptr->ref_obj_id = reg->ref_obj_id;
> +		}

Nit: Maybe fill `initialized_dynptr` unconditionally (regardless of
     MEM_UNINIT check above I mean)?
     Remembering under which conditions it is filled might be a bit
     cumbersome when working with this function in the future.

[...]