[PATCH net 1/4] mptcp: sockopt: set timestamp flags on subflow socket, not msk

From: Matthieu Baerts (NGI0)

Date: Mon Apr 27 2026 - 15:55:44 EST


From: Gang Yan <yangang@xxxxxxxxxx>

Both mptcp_setsockopt_sol_socket_tstamp() and
mptcp_setsockopt_sol_socket_timestamping() iterate over subflows,
acquire the subflow socket lock, but then erroneously pass the MPTCP
msk socket to sock_set_timestamp() / sock_set_timestamping() instead
of the subflow ssk. As a result, the timestamp flags are set on the
wrong socket and have no effect on the actual subflows.

Pass ssk instead of sk to both helpers.

Fixes: 9061f24bf82e ("mptcp: sockopt: propagate timestamp request to subflows")
Cc: stable@xxxxxxxxxxxxxxx
Assisted-by: GLM:5.1
Signed-off-by: Gang Yan <yangang@xxxxxxxxxx>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
---
net/mptcp/sockopt.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index de90a2897d2d..79db15903e7a 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -161,7 +161,7 @@ static int mptcp_setsockopt_sol_socket_tstamp(struct mptcp_sock *msk, int optnam
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
bool slow = lock_sock_fast(ssk);

- sock_set_timestamp(sk, optname, !!val);
+ sock_set_timestamp(ssk, optname, !!val);
unlock_sock_fast(ssk, slow);
}

@@ -237,7 +237,7 @@ static int mptcp_setsockopt_sol_socket_timestamping(struct mptcp_sock *msk,
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
bool slow = lock_sock_fast(ssk);

- sock_set_timestamping(sk, optname, timestamping);
+ sock_set_timestamping(ssk, optname, timestamping);
unlock_sock_fast(ssk, slow);
}


--
2.53.0