Re: [PATCH net-next] selftests: net: Add a missing config option

On 7/29/26 10:44 PM, Alice Mikityanska wrote:

On Mon, 27 Jul 2026 at 12:09, Matthieu Baerts [off-list ref] wrote:

quoted

On 23/07/2026 16:02, Alice Mikityanska wrote:

quoted

From: Alice Mikityanska <redacted>

Commit 5cb53743e1ff ("selftests: net: Add a test for BIG TCP in UDP
tunnels") used iptables match comment, which was missed from the CI
kernel config. Add the missing config option.

It helps, the CI can now run this test!

Reviewed-by: Matthieu Baerts <matttbe@kernel.org>


But I think another follow-up patch is required, because this test is
flaky when using a debug kernel config:


https://netdev.bots.linux.dev/flakes.html?min-flip=0&tn-needle=big-tcp-tunnels-sh

Maybe because wait_local_port_listen() is required after having called
netserver?

The issue is hard to reproduce on my machine, but I could reproduce it
in ~12 hours of non-stop testing in a loop. It reproduces even with
wait_local_port_listen, so it must be something else. The log above
(and my repro attempts) shows that it fails in a non-first test, but
netserver starts only once, before the first test. If the failure was
due to netserver not being ready, it would fail in the first test.
I'll keep investigating.

I *think* this kind of flakes are sort of expected for 'performance'
related tests when running on debug kernel: the environment can be
painful slow, and few failed iterations I saw has csum offload disabled
- even lower expected tput.

AFAICS the target packet number is independent from KSFT_MACHINE_SLOW
and the actual offload setting. Possibly you can tune the target value a
bit WRT the mentioned variables or skip entirely pkts number validation
in the slowest permutation (note that the self-test will still have some
value due to code coverage with sanitizers enabled).

/p