diff --git a/os4-ref/src/task/task.rs b/os4-ref/src/task/task.rs
index 892d2bf..69030e1 100644
--- a/os4-ref/src/task/task.rs
+++ b/os4-ref/src/task/task.rs
@@ -58,6 +58,7 @@ impl TaskControlBlock {
 #[derive(Copy, Clone, PartialEq)]
 /// task status: UnInit, Ready, Running, Exited
 pub enum TaskStatus {
+    UnInit,
     Ready,
     Running,
     Exited,