This is a note to let you know that I've just added the patch titled

    mptcp: continue marking the first subflow as UNCONNECTED

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mptcp-continue-marking-the-first-subflow-as-unconnected.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From matttbe@kernel.org  Mon Mar  4 09:10:32 2024
From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>
Date: Wed, 28 Feb 2024 18:21:21 +0100
Subject: mptcp: continue marking the first subflow as UNCONNECTED
To: stable@vger.kernel.org, gregkh@linuxfoundation.org, sashal@kernel.org
Cc: MPTCP Upstream <mptcp@lists.linux.dev>, "Matthieu Baerts (NGI0)" <matttbe@kernel.org>
Message-ID: <20240228172121.243458-2-matttbe@kernel.org>

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

After the 'Fixes' commit mentioned below, which is a partial backport,
the MPTCP worker was no longer marking the first subflow as "UNCONNECTED"
when the socket was transitioning to TCP_CLOSE state.

As a result, in v6.1, it was no longer possible to reconnect to the just
disconnected socket. Continue to do that like before, only for the first
subflow.

A few refactoring have been done around the 'msk->subflow' in later
versions, and it looks like this is not needed to do that there, but
still needed in v6.1. Without that, the 'disconnect' tests from the
mptcp_connect.sh selftest fail: they repeat the transfer 3 times by
reconnecting to the server each time.

Fixes: 7857e35ef10e ("mptcp: get rid of msk->subflow")
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/mptcp/protocol.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index cdabb00648bd2..125825db642cc 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2440,6 +2440,8 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 	need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk);
 	if (!dispose_it) {
 		__mptcp_subflow_disconnect(ssk, subflow, flags);
+		if (msk->subflow && ssk == msk->subflow->sk)
+			msk->subflow->state = SS_UNCONNECTED;
 		release_sock(ssk);
 
 		goto out;
-- 
2.43.0



Patches currently in stable-queue which might be from matttbe@kernel.org are

queue-5.4/mptcp-continue-marking-the-first-subflow-as-unconnected.patch

On Mon, Mar 04, 2024 at 09:11:22AM +0100, gregkh@linuxfoundation.org wrote:
> 
> This is a note to let you know that I've just added the patch titled
> 
>     mptcp: continue marking the first subflow as UNCONNECTED
> 
> to the 5.4-stable tree which can be found at:
>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

Oops, nope, my fault, this doesn't go to 5.4.y, sorry for the noise.

greg k-h