diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 20505cafa29904f176b735f98cdc94eeaac50181..0643e5bc9f41310b78f5b8cc36cc7abb6175e4f3 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -514,7 +514,7 @@ static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out)
 		goto out;
 	}
 
-	fd = os_open_file(ubd_dev->file, global_openflags, 0);
+	fd = os_open_file(ubd_dev->file, of_read(OPENFLAGS()), 0);
 	if (fd < 0)
 		return fd;