diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index f02bfcc282e5a8330241fa834ac50081327e05eb..ecd16541896b509dd0dc3f104bb9f4b1373ca805 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -1066,11 +1066,19 @@ isert_rx_opcode(struct isert_conn *isert_conn, struct iser_rx_desc *rx_desc,
 {
 	struct iscsi_hdr *hdr = &rx_desc->iscsi_header;
 	struct iscsi_conn *conn = isert_conn->conn;
+	struct iscsi_session *sess = conn->sess;
 	struct iscsi_cmd *cmd;
 	struct isert_cmd *isert_cmd;
 	int ret = -EINVAL;
 	u8 opcode = (hdr->opcode & ISCSI_OPCODE_MASK);
 
+	if (sess->sess_ops->SessionType &&
+	   (!(opcode & ISCSI_OP_TEXT) || !(opcode & ISCSI_OP_LOGOUT))) {
+		pr_err("Got illegal opcode: 0x%02x in SessionType=Discovery,"
+		       " ignoring\n", opcode);
+		return 0;
+	}
+
 	switch (opcode) {
 	case ISCSI_OP_SCSI_CMD:
 		cmd = iscsit_allocate_cmd(conn, GFP_KERNEL);