diff --git a/net/ceph/messenger_v1.c b/net/ceph/messenger_v1.c
index c9e002d96319..b3ff3274344e 100644
--- a/net/ceph/messenger_v1.c
+++ b/net/ceph/messenger_v1.c
@@ -887,6 +887,12 @@ static int process_connect(struct ceph_connection *con)
 			return -1;
 		}
 
+		if (le32_to_cpu(con->v1.in_reply.connect_seq) !=
+		    con->v1.connect_seq + 1) {
+			con->error_msg = "protocol error, bad connect_seq";
+			return -1;
+		}
+
 		WARN_ON(con->state != CEPH_CON_S_V1_CONNECT_MSG);
 		con->state = CEPH_CON_S_OPEN;
 		con->v1.auth_retry = 0;    /* we authenticated; clear flag */
@@ -898,8 +904,6 @@ static int process_connect(struct ceph_connection *con)
 		     con->v1.peer_global_seq,
 		     le32_to_cpu(con->v1.in_reply.connect_seq),
 		     con->v1.connect_seq);
-		WARN_ON(con->v1.connect_seq !=
-			le32_to_cpu(con->v1.in_reply.connect_seq));
 
 		if (con->v1.in_reply.flags & CEPH_MSG_CONNECT_LOSSY)
 			ceph_con_flag_set(con, CEPH_CON_F_LOSSYTX);