diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 3977332c44c0..bdfeecea814f 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -1538,6 +1538,10 @@ int mptcp_set_rcvlowat(struct sock *sk, int val)
 	struct mptcp_subflow_context *subflow;
 	int space, cap;
 
+	/* bpf can land here with a wrong sk type */
+	if (sk->sk_protocol == IPPROTO_TCP)
+		return -EINVAL;
+
 	if (sk->sk_userlocks & SOCK_RCVBUF_LOCK)
 		cap = sk->sk_rcvbuf >> 1;
 	else