Re: Patch "mptcp: move the whole rx path under msk socket lock protection" has been added to the 6.12-stable tree

[Matthieu Baerts <matttbe@kernel.org>]

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;a=summary
> 
> 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-v1-3-4a47d90d7998@kernel.org
> 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
-- 
Sponsored by the NGI0 Core fund.