Re: [PATCH v2 bpf 3/3] selftests/bpf: add edge case backtracking logic test

Andrii Nakryiko
2023-11-10T06:39:23Z

On Thu, Nov 9, 2023 at 8:14 PM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Thu, Nov 9, 2023 at 8:05 PM Andrii Nakryiko
> <andrii.nakryiko@gmail.com> wrote:
> >
> > >
> > > When I was analysing and crafting the test I for some reason assumed I
> > > need to have a jump inside the state that won't trigger state
> > > checkpoint. But I think that's not necessary, just doing conditional
> > > jump and jumping back an instruction or two should do. With that yes,
> > > TEST_STATE_FREQ should be a better way to do this.
> >
> > Ah, ok, TEST_STATE_FREQ won't work. It triggers state checkpointing
> > both at conditional jump instruction and on its target, because target
> > is prune point.
> >
> > So I think this test has to be the way it is.
>
> I see.
> I was about to apply it, but then noticed:
> numamove_bpf-numamove_bpf.o |migrate_misplaced_page |success ->
> failure (!!)|-100.00 %
>
> veristat is not known for sporadic failures.
> Is this a real issue?

No idea what this is, I don't have it in my local object files, will
need to regenerate them and check.