diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index a709df659ae0eb..1d05d9841b5cc3 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -490,4 +490,14 @@ static inline void mptcp_do_fallback(struct sock *sk)
 
 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)
 
+static inline bool subflow_simultaneous_connect(struct sock *sk)
+{
+	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+	struct sock *parent = subflow->conn;
+
+	return sk->sk_state == TCP_ESTABLISHED &&
+	       !mptcp_sk(parent)->pm.server_side &&
+	       !subflow->conn_finished;
+}
+
 #endif /* __MPTCP_PROTOCOL_H */
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index cb8a42ff4646e7..548f9e347ff51d 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -1128,6 +1128,16 @@ static void subflow_state_change(struct sock *sk)
 
 	__subflow_state_change(sk);
 
+	if (subflow_simultaneous_connect(sk)) {
+		mptcp_do_fallback(sk);
+		pr_fallback(mptcp_sk(parent));
+		subflow->conn_finished = 1;
+		if (inet_sk_state_load(parent) == TCP_SYN_SENT) {
+			inet_sk_state_store(parent, TCP_ESTABLISHED);
+			parent->sk_state_change(parent);
+		}
+	}
+
 	/* as recvmsg() does not acquire the subflow socket for ssk selection
 	 * a fin packet carrying a DSS can be unnoticed if we don't trigger
 	 * the data available machinery here.