Re: [PATCH bpf-next 3/7] bpf: enforce precision for r0 on callback return

Eduard Zingerman
2023-11-09T18:03:58Z

On Thu, 2023-11-09 at 10:01 -0800, Andrii Nakryiko wrote:
[...]
> > Just like Ed I was also initially confused by this.
> > As you said check_return_code() has the same problem.
> > I think the issue this patch and similar in check_return_code()
> > should be fixing is the case where one state went through
> > ret code checking, but another state with potentially out-of-range
> > r0 got state pruned since r0 wasn't marked precise.
>
> Right.
>
> > Not sure how hard it would be to come up with a selftest for such a scenario.
>
> Yep, I'll think of something. Lots of tests to come up with :)

Hm, range argument is convincing, thank you.