diff --git a/kernel/core/include/tos_version.h b/kernel/core/include/tos_version.h
index 4520fd5d..2b7d353a 100644
--- a/kernel/core/include/tos_version.h
+++ b/kernel/core/include/tos_version.h
@@ -25,8 +25,8 @@
 
 #define TOS_VERSION_MAJOR   0x02
 #define TOS_VERSION_MINOR   0x04
-#define TOS_VERSION_PATCH   0x04
-#define TOS_VERSION "2.4.4"
+#define TOS_VERSION_PATCH   0x05
+#define TOS_VERSION "2.4.5"
 
 #endif /* _TOS_VERSION_H_ */
 
diff --git a/kernel/core/tos_sched.c b/kernel/core/tos_sched.c
index 9bb24a7d..b6ea129f 100644
--- a/kernel/core/tos_sched.c
+++ b/kernel/core/tos_sched.c
@@ -140,6 +140,11 @@ __KNL__ void readyqueue_remove(k_task_t *task)
     k_prio_t task_prio;
     k_list_t *task_list;
 
+    // protect the idle task.
+    if (knl_is_idle(task)) {
+        return;
+    }
+
     task_prio = task->prio;
     task_list = &k_rdyq.task_list_head[task_prio];