Re: [PATCH 5.10] mptcp: pm: kernel: flush: do not reset ADD_ADDR limit

Hi Maximilian,

On 10/09/2025 11:28, Heyne, Maximilian wrote:

From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>

commit 68fc0f4b0d25692940cdc85c68e366cae63e1757 upstream.

A flush of the MPTCP endpoints should not affect the MPTCP limits. In
other words, 'ip mptcp endpoint flush' should not change 'ip mptcp
limits'.

But it was the case: the MPTCP_PM_ATTR_RCV_ADD_ADDRS (add_addr_accepted)
limit was reset by accident. Removing the reset of this counter during a
flush fixes this issue.

Fixes: 01cacb00b35c ("mptcp: add netlink-based PM")
Cc: stable@vger.kernel.org
Reported-by: Thomas Dreibholz <redacted>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/579
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20250815-net-mptcp-misc-fixes-6-17-rc2-v1-2-521fe9957892@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[adjusted patch by removing WRITE_ONCE to take into account the missing
 commit 72603d207d59 ("mptcp: use WRITE_ONCE for the pernet *_max")]
Signed-off-by: Maximilian Heyne <redacted>
---
For some reason only the corresponding selftest patch was backported and
it's now failing on 5.10 kernels. I tested that with this patch the
selftest is succeeding again.

Thank you for this backport. It looks good to me!

Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>


I was waiting for the FAILED notification for this patch before adapting
it for v5.10, but it looks like I never got it, see:

https://lore.kernel.org/017c0cd3-7391-4d53-9e3e-ebdea5fa26da@kernel.org (local)

No problem, that was not critical, and we now have a fix :)

Cheers,
Matt
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