diff --git a/src/clock.c b/src/clock.c
index 045555933d..191525411a 100644
--- a/src/clock.c
+++ b/src/clock.c
@@ -13,7 +13,8 @@
  * 2010-07-13     Bernard      fix rt_tick_from_millisecond issue found by kuronca
  * 2011-06-26     Bernard      add rt_tick_set function.
  * 2018-11-22     Jesven       add per cpu tick
- * 2020-12-29     Meco Man     add function rt_tick_get_millisecond()
+ * 2020-12-29     Meco Man     implement rt_tick_get_millisecond()
+ * 2021-06-01     Meco Man     add critical section projection for rt_tick_increase()
  */
 
 #include <rthw.h>
diff --git a/src/idle.c b/src/idle.c
index 59868352d8..e73a78be9c 100644
--- a/src/idle.c
+++ b/src/idle.c
@@ -202,12 +202,14 @@ static void rt_thread_idle_entry(void *parameter)
     {
 #ifdef RT_USING_IDLE_HOOK
         rt_size_t i;
+        void (*idle_hook)(void);
 
         for (i = 0; i < RT_IDLE_HOOK_LIST_SIZE; i++)
         {
-            if (idle_hook_list[i] != RT_NULL)
+            idle_hook = idle_hook_list[i];
+            if (idle_hook != RT_NULL)
             {
-                idle_hook_list[i]();
+                idle_hook();
             }
         }
 #endif