diff --git a/os/rt/include/chschd.h b/os/rt/include/chschd.h
index 6af0cdedb..f442286c9 100644
--- a/os/rt/include/chschd.h
+++ b/os/rt/include/chschd.h
@@ -490,12 +490,6 @@ struct ch_system {
    */
   kernel_stats_t        kernel_stats;
 #endif
-#if CH_CFG_NO_IDLE_THREAD == FALSE
-  /**
-   * @brief   Idle thread working area.
-   */
-  THD_WORKING_AREA(idle_thread_wa, PORT_IDLE_THREAD_STACK_SIZE);
-#endif
 };
 
 /*===========================================================================*/
diff --git a/os/rt/src/chsys.c b/os/rt/src/chsys.c
index d9ca6d81a..850b9b5a9 100644
--- a/os/rt/src/chsys.c
+++ b/os/rt/src/chsys.c
@@ -39,6 +39,13 @@
 /* Module exported variables.                                                */
 /*===========================================================================*/
 
+#if (CH_CFG_NO_IDLE_THREAD == FALSE) || defined(__DOXYGEN__)
+/**
+ * @brief   Idle thread working area.
+ */
+THD_WORKING_AREA(ch_idle_thread_wa, PORT_IDLE_THREAD_STACK_SIZE);
+#endif
+
 /*===========================================================================*/
 /* Module local types.                                                       */
 /*===========================================================================*/
@@ -152,8 +159,8 @@ void chSysInit(void) {
   {
     static const thread_descriptor_t idle_descriptor = {
       "idle",
-      THD_WORKING_AREA_BASE(ch.idle_thread_wa),
-      THD_WORKING_AREA_END(ch.idle_thread_wa),
+      THD_WORKING_AREA_BASE(ch_idle_thread_wa),
+      THD_WORKING_AREA_END(ch_idle_thread_wa),
       IDLEPRIO,
       _idle_thread,
       NULL