diff --git a/iscsi-scst/kernel/iscsi.c b/iscsi-scst/kernel/iscsi.c
index 4dc07f0b4..58ba36dfd 100644
--- a/iscsi-scst/kernel/iscsi.c
+++ b/iscsi-scst/kernel/iscsi.c
@@ -2035,6 +2035,8 @@ static int scsi_cmnd_start(struct iscsi_cmnd *req)
 	atomic_inc(&session->active_cmds);
 	req->dec_active_cmds = 1;
 
+	sBUG_ON(session->scst_sess == NULL);
+
 	scst_cmd = scst_rx_cmd(session->scst_sess,
 		(uint8_t *)&req_hdr->lun, sizeof(req_hdr->lun),
 		req_hdr->scb, sizeof(req_hdr->scb), SCST_NON_ATOMIC);
diff --git a/iscsi-scst/kernel/isert-scst/iser_rdma.c b/iscsi-scst/kernel/isert-scst/iser_rdma.c
index ab8b2aa16..c856f15d5 100644
--- a/iscsi-scst/kernel/isert-scst/iser_rdma.c
+++ b/iscsi-scst/kernel/isert-scst/iser_rdma.c
@@ -1271,7 +1271,7 @@ static void isert_kref_free(struct kref *kref)
 
 	TRACE_ENTRY();
 
-	pr_info("isert_conn_free conn:%p\n", isert_conn);
+	pr_info("%s conn:%p\n", __func__, isert_conn);
 
 	isert_free_conn_resources(isert_conn);
 
@@ -1306,6 +1306,7 @@ static void isert_kref_free(struct kref *kref)
 
 void isert_conn_free(struct isert_connection *isert_conn)
 {
+	sBUG_ON(atomic_read(&isert_conn->kref.refcount) == 0);
 	kref_put(&isert_conn->kref, isert_kref_free);
 }