diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 1acd4e37a0ea..370afcac2623 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2708,8 +2708,8 @@ void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout)
 	if (!fail_tout && !inet_csk(sk)->icsk_mtup.probe_timestamp)
 		return;
 
-	close_timeout = inet_csk(sk)->icsk_mtup.probe_timestamp - tcp_jiffies32 + jiffies +
-			TCP_TIMEWAIT_LEN;
+	close_timeout = (unsigned long)inet_csk(sk)->icsk_mtup.probe_timestamp -
+			tcp_jiffies32 + jiffies + TCP_TIMEWAIT_LEN;
 
 	/* the close timeout takes precedence on the fail one, and here at least one of
 	 * them is active