Re: [PATCH bpf-next v7 2/6] bpf: Attribute async callback instructions to verification roots

[Eduard Zingerman <eddyz87@gmail.com>]

On Sat, 2026-08-08 at 08:25 +0200, Kumar Kartikeya Dwivedi wrote:

...

> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index 855f245e7468..9b76851dcf54 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -18762,6 +18762,7 @@ static int do_check_subprogs(struct bpf_verifier_env *env)
>  	struct bpf_prog_aux *aux = env->prog->aux;
>  	struct bpf_func_info_aux *sub_aux;
>  	int i, ret, new_cnt;
> +	u32 insn_processed;
>  
>  	if (!aux->func_info)
>  		return 0;
> @@ -18780,9 +18781,11 @@ static int do_check_subprogs(struct bpf_verifier_env *env)
>  		if (!sub_aux->called || sub_aux->verified)
>  			continue;
>  
> +		insn_processed = env->insn_processed;
>  		env->insn_idx = env->subprog_info[i].start;
>  		WARN_ON_ONCE(env->insn_idx == 0);
>  		ret = do_check_common(env, i);
> +		env->subprog_info[i].insns_total = env->insn_processed - insn_processed;
>  		if (ret) {
>  			return ret;
>  		} else if (env->log.level & BPF_LOG_LEVEL) {
> @@ -18809,10 +18812,12 @@ static int do_check_subprogs(struct bpf_verifier_env *env)
>  
>  static int do_check_main(struct bpf_verifier_env *env)
>  {
> +	u32 insn_processed = env->insn_processed;
>  	int ret;
>  
>  	env->insn_idx = 0;
>  	ret = do_check_common(env, 0);
> +	env->subprog_info[0].insns_total = env->insn_processed - insn_processed;

Let's move this accounting inside do_check_common().
Also, having a comment like:

/*
 * The override is needed to account for async subprograms,
 * which are verified with their own set of stack frames and
 * thus are not accounted as callees by account_current_path().
 * Accumulate their total counts as total counts of the main
 * or global subprog hosting the async call.
 */

would be helpful.

>  	if (!ret)
>  		env->prog->aux->stack_depth = env->subprog_info[0].stack_depth;
>  	return ret;