Re: [PATCH v11 bpf-next 01/12] bpf, x86: add new map type: instructions array

[Anton Protopopov <a.s.protopopov@gmail.com>]

On 25/11/05 06:03PM, Alexei Starovoitov wrote:
> On Wed, Nov 5, 2025 at 12:58 AM Anton Protopopov
> <a.s.protopopov@gmail.com> wrote:
> > @@ -21695,6 +21736,8 @@ static int jit_subprogs(struct bpf_verifier_env *env)
> >                 func[i]->aux->jited_linfo = prog->aux->jited_linfo;
> >                 func[i]->aux->linfo_idx = env->subprog_info[i].linfo_idx;
> >                 func[i]->aux->arena = prog->aux->arena;
> > +               func[i]->aux->used_maps = env->used_maps;
> > +               func[i]->aux->used_map_cnt = env->used_map_cnt;
> 
> ...
> 
> > It might be called before the used_maps are copied into aux...
> 
> wat?

It is called from fixup_call_arg() which happens before
the env->prog->aux->used_maps is populated as a copy of
env->used_maps.

In any case, I will take a closer look and follow up on
this after Kubecon (which is the next week).

> on top of the set:
> diff --git a/kernel/bpf/bpf_insn_array.c b/kernel/bpf/bpf_insn_array.c
> index 61ce52882632..97fcde6d7f07 100644
> --- a/kernel/bpf/bpf_insn_array.c
> +++ b/kernel/bpf/bpf_insn_array.c
> @@ -278,8 +278,8 @@ void bpf_prog_update_insn_ptrs(struct bpf_prog
> *prog, u32 *offsets, void *image)
>         if (!offsets || !image)
>                 return;
> 
> -       for (i = 0; i < prog->aux->used_map_cnt; i++) {
> -               map = prog->aux->used_maps[i];
> +       for (i = 0; i < prog->aux->main_prog_aux->used_map_cnt; i++) {
> +               map = prog->aux->main_prog_aux->used_maps[i];
>                 if (!is_insn_array(map))
>                         continue;
> 
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index 1268fa075d4c..53b9a6cee156 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -22096,8 +22096,6 @@ static int jit_subprogs(struct bpf_verifier_env *env)
>                 func[i]->aux->jited_linfo = prog->aux->jited_linfo;
>                 func[i]->aux->linfo_idx = env->subprog_info[i].linfo_idx;
>                 func[i]->aux->arena = prog->aux->arena;
> -               func[i]->aux->used_maps = env->used_maps;
> -               func[i]->aux->used_map_cnt = env->used_map_cnt;
>                 num_exentries = 0;
>                 insn = func[i]->insnsi;
>                 for (j = 0; j < func[i]->len; j++, insn++) {
> 
> 
> all tests still pass.
> 
> If I'm not missing anything, please send a follow up.
> 
> The plan is to split prog_aux into main and subprog,
> and subprog will be a fraction of main.
> Right now we copy more and more fields for no good reason.
> Let's avoid this.