Re: [PATCH mptcp-net v2 2/6] selftests: mptcp: join: rm: set backup flag

[Matthieu Baerts <matttbe@kernel.org>]

Hi Geliang,

Thank you for the review.

4 Nov 2025 07:06:34 Geliang Tang <geliang@kernel.org>:

> Hi Matt,
>
> Thanks for this fix. It works indeed.
>
> On Sun, 2025-11-02 at 12:30 +0100, Matthieu Baerts (NGI0) wrote:
>> Some of these 'remove' tests rarely fail because a subflow has been
>
> In my testing, only the "flush addresses" test case fails
> intermittently. I'm wondering which other test cases have failed in
> your environment?

I took the unstable ones from the Netdev and MPTCP CIs:

https://netdev.bots.linux.dev/contest.html?pass=0&executor=vmksft-mptcp-dbg&ld-cases=1

https://ci-results.mptcp.dev/flakes.html

> I'm thinking we shouldn't add the "backup" flag to every test in
> remove_tests, but only to the specific ones that are actually failing.
>
> Similarly for patches 3 and 4, we don't need to add "test_linkfail=128"
> to every test. We should only apply it to the specific ones that are
> actually failing.

If my analysis is correct, it means the simple fixes I did (backup and
longer file size) can be applied to multiple tests. Then probably better
to avoid these other tests to fail for the same reasons even if it is very
rare, and very hard to reproduce, no? Each false positive takes a lot of
resources (mainly time) to debug.

Cheers,
Matt