diff --git a/ostd/src/util/vaddr_alloc.rs b/ostd/src/util/vaddr_alloc.rs
index 7a8353f0..f4f53c12 100644
--- a/ostd/src/util/vaddr_alloc.rs
+++ b/ostd/src/util/vaddr_alloc.rs
@@ -9,7 +9,7 @@ use crate::{
     Error,
 };
 
-pub struct KVirtAreaFreeNode {
+struct KVirtAreaFreeNode {
     block: Range<Vaddr>,
 }