[PATCH net 4/4] mptcp: sockopt: increase seq in mptcp_setsockopt_all_sf

Matthieu Baerts (NGI0)
2026-05-01T19:36:22Z

mptcp_setsockopt_all_sf() was missing a call to sockopt_seq_inc(). This
is required not to cause missing synchronization for newer subflows
created later on.

This helper is called each time a socket option is set on subflows, and
future ones will need to inherit this option after their creation.

Fixes: 51c5fd09e1b4 ("mptcp: add TCP_MAXSEG sockopt support")
Cc: stable@vger.kernel.org
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
net/mptcp/sockopt.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 0efe40be2fde..1cf608e7357b 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -812,6 +812,10 @@ static int mptcp_setsockopt_all_sf(struct mptcp_sock *msk, int level,
if (ret)
break;
}
+
+ if (!ret)
+ sockopt_seq_inc(msk);
+
return ret;
}

--
2.53.0