On Fri, Nov 17, 2023 at 5:34 PM Eduard Zingerman <eddyz87@xxxxxxxxx> wrote:
>
> diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
> index 7def320aceef..71b7c7c39cea 100644
> --- a/include/linux/bpf_verifier.h
> +++ b/include/linux/bpf_verifier.h
> @@ -301,6 +301,15 @@ struct bpf_func_state {
> struct tnum callback_ret_range;
> bool in_async_callback_fn;
> bool in_exception_callback_fn;
> + /* For callback calling functions that limit number of possible
> + * callback executions (e.g. bpf_loop) keeps track of current
> + * simulated iteration number. When non-zero either:
> + * - current frame has a child frame, in such case it's callsite points
> + * to callback calling function;
> + * - current frame is a topmost frame, in such case callback has just
> + * returned and env->insn_idx points to callback calling function.
> + */
> + u32 callback_depth;
The first part of the comment makes sense, but the second...
What are you trying to explain with the second part ?
How does the knowledge of insn_idx help here ? or helps to
understand the rest of the patch?
