Re: [PATCH net] selftests: net: add missing required classifier

[Paolo Abeni <pabeni@redhat.com>]

On Thu, 2024-01-25 at 15:10 +0100, Eric Dumazet wrote:
> On Thu, Jan 25, 2024 at 12:38 PM Paolo Abeni <pabeni@redhat.com> wrote:
> > 
> > On Thu, 2024-01-25 at 09:48 +0100, Eric Dumazet wrote:
> > > On Thu, Jan 25, 2024 at 9:23 AM Paolo Abeni <pabeni@redhat.com> wrote:
> > > > 
> > > > the udpgro_fraglist self-test uses the BPF classifiers, but the
> > > > current net self-test configuration does not include it, causing
> > > > CI failures:
> > > > 
> > > >  # selftests: net: udpgro_frglist.sh
> > > >  # ipv6
> > > >  # tcp - over veth touching data
> > > >  # -l 4 -6 -D 2001:db8::1 -t rx -4 -t
> > > >  # Error: TC classifier not found.
> > > >  # We have an error talking to the kernel
> > > >  # Error: TC classifier not found.
> > > >  # We have an error talking to the kernel
> > > > 
> > > > Add the missing knob.
> > > > 
> > > > Fixes: edae34a3ed92 ("selftests net: add UDP GRO fraglist + bpf self-tests")
> > > > Signed-off-by: Paolo Abeni <pabeni@redhat.com>
> > > 
> > > FYI, while looking at the gro test, I found that using strace was
> > > making it failing as well.
> > 
> > It looks like the gro.sh (large) tests send the to-be-aggregate
> > segments individually and relay on the gro flush timeout being large
> > enough to fit all the relevant write operations. I suspect/hope
> > something alike:
> > 
> > ---
> > diff --git a/tools/testing/selftests/net/setup_veth.sh b/tools/testing/selftests/net/setup_veth.sh
> > index a9a1759e035c..1f78a87f6f37 100644
> > --- a/tools/testing/selftests/net/setup_veth.sh
> > +++ b/tools/testing/selftests/net/setup_veth.sh
> > @@ -11,7 +11,7 @@ setup_veth_ns() {
> >         local -r ns_mac="$4"
> > 
> >         [[ -e /var/run/netns/"${ns_name}" ]] || ip netns add "${ns_name}"
> > -       echo 100000 > "/sys/class/net/${ns_dev}/gro_flush_timeout"
> > +       echo 1000000 > "/sys/class/net/${ns_dev}/gro_flush_timeout"
> >         ip link set dev "${ns_dev}" netns "${ns_name}" mtu 65535
> >         ip -netns "${ns_name}" link set dev "${ns_dev}" up
> > ---
> > should solve the sporadic issues.
> 
> I think you are right.
> 
> I tried multiple values, and found 600,000 was not enough in some cases.
> 
> With 1,000,000, I was able to run the test (with the strace overhead)
> 100 times without a single failure.

Thank you for testing!

Do you prefer I'll send the formal patch or do you prefer otherwise? 

Cheers,

Paolo