dumpcap: weird failure with six IPv6 hosts in the filter

[Isaac Boukris]

On Mon, Jun 17, 2024 at 6:30 PM Stephen Hemminger
<stephen at networkplumber.org> wrote:
>
> On Mon, 17 Jun 2024 10:11:47 +0300
> Isaac Boukris <iboukris at gmail.com> wrote:
>
> > Hi Stephen,
> >
> > For instance, the following filter fais as follows (if I omit one host
> > it works):
> > -f "host 1::1 or host 1::1 or host 1::1 or host 1::1 or host 1::1 or host 1::1"
> >
> > EAL: Error - exiting with code: 1
> >   Cause: Packet dump enable on 0:0000:13:00.0 failed Connection timed out
> >
> > On the server side I see:
> > Jun 16 15:17:08: EAL: failed to send to
> > (/tmp/dpdk/rte/mp_socket_262131_4a103955de0b7a) due to No such file or
> > directory
> > Jun 16 15:17:08: pdump_server(): failed to send to client:No such file
> > or directory
> > Jun 16 15:17:08: EAL: Fail to handle message: mp_pdump
> >
> > Then subsequent requests fail with (even with no filter):
> > pdump_register_rx_callbacks(): rx callback for port=0 queue=0, already exists
> >
> > I debugged the dpdk-mp-msg thread with gdb, as far as I can tell it
> > hangs an awful lot of time on rte_bpf_load() (~15 secs in my env), so
> > the client times out and by the time the server tries to respond the
> > client socket doesn't exist anymore.
> >
> > Thoughts?
>
> I tried testing this with current 24.07-rc code base and do not see any problem
> (don't have real hardware needed to fix vdev to get tap to work).
>
> # ./build/app/dpdk-dumpcap -f "host 1::1 or host 1::1 or host 1::1 or host 1::1 or host 1::1 or host 1::1"
> File: /tmp/dpdk-dumpcap_0_net_tap0_20240617082758.pcapng
> Capturing on 'net_tap0'
> Packets captured: 0 ^C
> Packets received/dropped on interface 'net_tap0': 0/0 (0.0)

Thanks for giving it a try, I had thought it would easily reproduce as
it does for me (perhaps worth trying adding a host or two).

I'll try a more recent dpdk version (currently running 23.11.0) and
try to narrow it further otherwise.