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

[Konstantin Ananyev <konstantin.v.ananyev@yandex.ru>]

28.06.2024 17:52, Isaac Boukris пишет:
> Hi Konstantin
> 
> On Fri, Jun 28, 2024 at 7:42 PM Konstantin Ananyev
> <konstantin.v.ananyev@yandex.ru> wrote:
>>
>>
>> Hi Isaac,
>>
>>>
>>> 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
>>
>>
>> In case you didn't get update from the bugzilla,
>> here is a patch to try, when you'll get a chance:
>> http://patchwork.dpdk.org/project/dpdk/list/?series=32321
> 
> I tested it yesterday and it solves the bug for me, the whole test
> takes less than a second now and dumpcap works just fine! I've posted
> the feedback on the bug :)

Ah ok, sorry I missed it somehow.
Thanks a lot for prompt update.
Konstantin