Re: [PATCH bpf-next v9 01/23] bpf/verifier: allow all functions to read user provided context

[Benjamin Tissoires]

On Fri, Sep 2, 2022 at 5:50 AM Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx> wrote:
>
> On Thu, 1 Sept 2022 at 18:48, Benjamin Tissoires
> <benjamin.tissoires@xxxxxxxxxx> wrote:
> >
> > [...]
> > If the above is correct, then yes, it would make sense to me to have 2
> > distinct functions: one to check for the args types only (does the
> > function definition in the problem matches BTF), and one to check for
> > its use.
> > Behind the scenes, btf_check_subprog_arg_match() calls
> > btf_check_func_arg_match() which is the one function with entangled
> > arguments type checking and actually assessing that the values
> > provided are correct.
> >
> > I can try to split that  btf_check_func_arg_match() into 2 distinct
> > functions, though I am not sure I'll get it right.
>
> FYI, I've already split them into separate functions in my tree
> because it had become super ugly at this point with all the new
> support and I refactored it to add the linked list helpers support
> using kfuncs (which requires some special handling for the args), so I
> think you can just leave it with a "processing_call" check in for your
> series for now.
>

great, thanks a lot.
Actually, writing the patch today with the "processing_call" was
really easy now that I have turned the problem in my head a lot
yesterday.

I am about to send v10 with the reviews addressed.

Cheers,
Benjamin