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