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

[Geliang Tang <geliang@kernel.org>]

Hi Matt,

On Tue, 2025-11-04 at 07:57 +0100, Matthieu Baerts wrote:
> 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.

I'll leave it to you to decide. However, I still believe it's better to
apply these fixes to the tests one by one, in case we see failures in
the future.

I'll respond with my Reviewed-by tag in the cover letter.

Thanks,
-Geliang

> 
> Cheers,
> Matt
>