Re: FAILED: patch "[PATCH] mptcp: pm: only decrement add_addr_accepted for MPJ req" failed to apply to 5.10-stable tree

[Matthieu Baerts <matttbe@kernel.org>]

Hi Greg,

On 26/08/2024 14:06, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 5.10-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.

Thank you for the notification!

(...)

> ------------------ original commit in Linus's tree ------------------
> 
> From 1c1f721375989579e46741f59523e39ec9b2a9bd Mon Sep 17 00:00:00 2001
> From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>
> Date: Mon, 19 Aug 2024 21:45:27 +0200
> Subject: [PATCH] mptcp: pm: only decrement add_addr_accepted for MPJ req
> 
> Adding the following warning ...
> 
>   WARN_ON_ONCE(msk->pm.add_addr_accepted == 0)
> 
> ... before decrementing the add_addr_accepted counter helped to find a
> bug when running the "remove single subflow" subtest from the
> mptcp_join.sh selftest.
> 
> Removing a 'subflow' endpoint will first trigger a RM_ADDR, then the
> subflow closure. Before this patch, and upon the reception of the
> RM_ADDR, the other peer will then try to decrement this
> add_addr_accepted. That's not correct because the attached subflows have
> not been created upon the reception of an ADD_ADDR.
> 
> A way to solve that is to decrement the counter only if the attached
> subflow was an MP_JOIN to a remote id that was not 0, and initiated by
> the host receiving the RM_ADDR.
> 
> Fixes: d0876b2284cf ("mptcp: add the incoming RM_ADDR support")

The code is too different in v5.10, and I don't think it is worth it to
have this small fix in v5.10.

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.