diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 1a32562..bf5bb7d 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -1814,9 +1814,22 @@
 			break;
 		}
 
+		l2cap_pi(sk)->mode = opts.mode;
+		switch (l2cap_pi(sk)->mode) {
+		case L2CAP_MODE_BASIC:
+			break;
+		case L2CAP_MODE_ERTM:
+		case L2CAP_MODE_STREAMING:
+			if (enable_ertm)
+				break;
+			/* fall through */
+		default:
+			err = -EINVAL;
+			break;
+		}
+
 		l2cap_pi(sk)->imtu = opts.imtu;
 		l2cap_pi(sk)->omtu = opts.omtu;
-		l2cap_pi(sk)->mode = opts.mode;
 		l2cap_pi(sk)->fcs  = opts.fcs;
 		l2cap_pi(sk)->max_tx = opts.max_tx;
 		l2cap_pi(sk)->tx_win = (__u8)opts.txwin_size;