[PATCH 7.2.y] mptcp: fix msk->timer_ival reset

["Matthieu Baerts (NGI0)" <matttbe@kernel.org>]

In this kernel version, icsk->icsk_rto_min is not initialised, because
this version doesn't contain commit ea4eb2adb0d3 ("mptcp: honour
configured min/max RTO in retransmit paths").

Reset it to TCP_RTO_MIN, which is how msk->timer_ival is also reset in
__mptcp_init_sock() in this version.

Fixes: 69a7b2a91267 ("mptcp: prevent race between disconnect() and rtx")
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/protocol.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 49c46498af96..5a97ed9487b8 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -3475,7 +3475,7 @@ static int mptcp_disconnect(struct sock *sk, int flags)
 	/* The later subflow close can not kick again the tout timer,
 	 * as the msk is already in closed status.
 	 */
-	msk->timer_ival = icsk->icsk_rto_min;
+	msk->timer_ival = TCP_RTO_MIN;
 	sk_stop_timer_sync(sk, &sk->mptcp_retransmit_timer);
 	icsk->icsk_mtup.probe_timestamp = 0;
 	sk_stop_timer_sync(sk, &icsk->mptcp_tout_timer);
-- 
2.55.0