Hi Greg, Sasha,

On 03/11/2025 02:29, gregkh@linuxfoundation.org wrote:

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

mptcp: move the whole rx path under msk socket lock protection

to the 6.12-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: mptcp-move-the-whole-rx-path-under-msk-socket-lock-protection.patch and it can be found in the queue-6.12 subdirectory.

Thank you for the backport!

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

Please drop this patch from the 6.12-stable tree: it causes troubles in the MPTCP selftests: MPTCP to TCP connections timeout when MSG_PEEK is used. Likely a dependence is missing, and it might be better to keep only the last patch, and resolve conflicts. I will check that ASAP.

In the meantime, can you then drop this patch and the ones that are linked to it please?

queue-6.12/mptcp-cleanup-mem-accounting.patch queue-6.12/mptcp-fix-msg_peek-stream-corruption.patch queue-6.12/mptcp-move-the-whole-rx-path-under-msk-socket-lock-protection.patch queue-6.12/mptcp-leverage-skb-deferral-free.patch

From stable+bounces-192095-greg=kroah.com@vger.kernel.org Mon Nov 3 08:27:43 2025 From: Sasha Levin sashal@kernel.org Date: Sun, 2 Nov 2025 18:27:32 -0500 Subject: mptcp: move the whole rx path under msk socket lock protection To: stable@vger.kernel.org Cc: Paolo Abeni pabeni@redhat.com, Mat Martineau martineau@kernel.org, "Matthieu Baerts (NGI0)" matttbe@kernel.org, Jakub Kicinski kuba@kernel.org, Sasha Levin sashal@kernel.org Message-ID: 20251102232735.3652847-1-sashal@kernel.org

From: Paolo Abeni pabeni@redhat.com

[ Upstream commit bc68b0efa1bf923cef1294a631d8e7416c7e06e4 ]

After commit c2e6048fa1cf ("mptcp: fix race in release_cb") we can move the whole MPTCP rx path under the socket lock leveraging the release_cb.

We can drop a bunch of spin_lock pairs in the receive functions, use a single receive queue and invoke __mptcp_move_skbs only when subflows ask for it.

This will allow more cleanup in the next patch.

Some changes are worth specific mention:

The msk rcvbuf update now always happens under both the msk and the subflow socket lock: we can drop a bunch of ONCE annotation and consolidate the checks.

When the skbs move is delayed at msk release callback time, even the msk rcvbuf update is delayed; additionally take care of such action in __mptcp_move_skbs().

Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org Link: https://patch.msgid.link/20250218-net-next-mptcp-rx-path-refactor-v1-3-4a47d... Signed-off-by: Jakub Kicinski kuba@kernel.org Stable-dep-of: 8e04ce45a8db ("mptcp: fix MSG_PEEK stream corruption") Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

(...)

Cheers, Matt