Re: [PATCH v4 bpf-next 1/2] bpf: properly verify tail call behavior

Alexei Starovoitov
2025-11-13T16:09:40Z

On Thu, Nov 13, 2025 at 3:46 AM Teichmann, Martin
<martin.teichmann@xfel.eu> wrote:
>
> Hi Eduard, Hi List,
>
> sorry for the late response.
>
> > This is a clever hack and I like it, but let's not do that.
> > It is going to be a footgun if e.g. someone would use
> > bpf_insn_successors() to build intra-procedural CFG.
>
> I appreciate the effort you've put into your solution. However, I feel that we might be leaning towards a YAGNI (You Ain't Gonna Need It) situation here. Sure, if somebody wants to do something like your CFG, my "hack" might pose problems. But what if not? In that case, your proposed solution just leads to additional complexity and unused code.

Disagree. Please do what Eduard suggested.

> In line with the tradition of the Linux kernel of keeping patches small, I can extract my three lines and the corresponding test, allowing us to proceed with my patch as a bug fix. You can then apply your adjustments for the stack liveness issue in your preferred manner.

that's not how it works. Please address the feedback.

pw-bot: cr