Re: dumpcap: weird failure with six IPv6 hosts in the filter

[Isaac Boukris <iboukris@gmail.com>]

Hi Konstantin,

On Wed, Jun 19, 2024 at 2:06 AM Konstantin Ananyev
<konstantin.v.ananyev@yandex.ru> wrote:
>
> 17.06.2024 22:40, Stephen Hemminger пишет:
> > On Mon, 17 Jun 2024 23:43:19 +0300
> > Isaac Boukris <iboukris@gmail.com> wrote:
> >
> >> On Mon, Jun 17, 2024 at 10:37 PM Isaac Boukris <iboukris@gmail.com> wrote:
> >>>
> >>>> Just a quick update that I still see the issue in my env with the
> >>>> master branch (24.07.0-rc0), I'm now testing by adding the filter to
> >>>> 'sample_filters' in test_bpf.c and running:
> >>>> time sudo build/app/dpdk-test bpf_convert_autotest
> >>>>
> >>>> With 5 hosts it takes less than 2 secs, with 6 it takes about 25 secs,
> >>>> i'll try to strace it maybe.
> >>>
> >>> strace was useless, no syscalls for ~18 secs, not sure how to debug it
> >>> further, valgrind / callgrind don't work on dpdk..
> >>>
> >>> It doesn't seem to be about the size though, I was able to produce
> >>> larger bpf code with ipv4 addresses and it worked fine too.
> >>
> >> Debugged a bit further with gdb, it looks like it is stuck in a while
> >> loop in lib/bpf/bpf_validate.c:evaluate(), there is a comment saying
> >> "make sure we evaluate each node only once" but it seem to go back and
> >> forth on the same idx's afaict.
> >
> > No idea, only original author understands the verifier.
> > Having our own unique verifier may not be a good idea.
> > There some other userspace BPF projects, seems like a good place for
> > convergence.
> >
> >
> > https://lpc.events/event/17/contributions/1639/attachments/1280/2585/userspace-ebpf-bpftime-lpc.pdf
>
> hi Isaac,
> please create a bug report in DPDK bugzilla.
> Ideally with a clear and simple way to reproduce
> the bug you are facing in the description.
> I'll try to have a look when I'll have some free time.
> Thanks
> Konstantin

Done:

https://bugs.dpdk.org/show_bug.cgi?id=1465

Thanks a lot!