Re: [PATCH AUTOSEL 6.13 13/17] mptcp: safety check before fallback

From: Sasha Levin
Date: Fri Mar 14 2025 - 21:39:35 EST


On Mon, Mar 03, 2025 at 06:05:12PM +0100, Matthieu Baerts wrote:
Hi Sasha,

On 03/03/2025 17:29, Sasha Levin wrote:
From: "Matthieu Baerts (NGI0)" <matttbe@xxxxxxxxxx>

[ Upstream commit db75a16813aabae3b78c06b1b99f5e314c1f55d3 ]

Recently, some fallback have been initiated, while the connection was
not supposed to fallback.

Add a safety check with a warning to detect when an wrong attempt to
fallback is being done. This should help detecting any future issues
quicker.

Acked-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
Link: https://patch.msgid.link/20250224-net-mptcp-misc-fixes-v1-3-f550f636b435@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

Thank you for backporting this patch, but is it OK to delay it a bit on
v6.13 and older please?

This patch depends on its parent commit, commit 8668860b0ad3 ("mptcp:
reset when MPTCP opts are dropped after join"), on kernels >=v5.19, to
avoid a WARN().

Waited a bit, looks ok to pull in now :)

--
Thanks,
Sasha