diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 2762148c169df206fae40da2230435f515b7d282..6c8114f77cfa54dbf9e13a0e09aca98f05de8021 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -274,7 +274,7 @@ static struct class uio_class = {
 	.dev_groups = uio_groups,
 };
 
-bool uio_class_registered;
+static bool uio_class_registered;
 
 /*
  * device functions