diff --git a/scst/src/dev_handlers/scst_vdisk.c b/scst/src/dev_handlers/scst_vdisk.c
index 2ec0d1177..9ec6e4af6 100644
--- a/scst/src/dev_handlers/scst_vdisk.c
+++ b/scst/src/dev_handlers/scst_vdisk.c
@@ -3322,6 +3322,8 @@ static enum compl_status_e fileio_exec_async(struct vdisk_cmd_params *p)
 		length = scst_get_buf_next(cmd, &address);
 	}
 
+	WARN_ON_ONCE(kvec - p->async.kvec != scst_get_buf_count(cmd));
+
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 20, 0)
 	iov_iter_kvec(&iter, dir, p->async.kvec, kvec - p->async.kvec, total);
 #else