diff --git a/libc/kernel/common/linux/timer.h b/libc/kernel/common/linux/timer.h
index 071a759..a113997 100644
--- a/libc/kernel/common/linux/timer.h
+++ b/libc/kernel/common/linux/timer.h
@@ -7,35 +7,37 @@
  ***   structures, and macros generated from the original header, and thus,
  ***   contains no copyrightable information.
  ***
+ ***   To edit the content of this header, modify the corresponding
+ ***   source file (e.g. under external/kernel-headers/original/) then
+ ***   run bionic/libc/kernel/tools/update_all.py
+ ***
+ ***   Any manual change here will be lost the next time this script will
+ ***   be run. You've been warned!
+ ***
  ****************************************************************************
  ****************************************************************************/
 #ifndef _LINUX_TIMER_H
 #define _LINUX_TIMER_H
-
 #include <linux/list.h>
 #include <linux/spinlock.h>
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #include <linux/stddef.h>
-
 struct tvec_t_base_s;
-
 struct timer_list {
  struct list_head entry;
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
  unsigned long expires;
-
  void (*function)(unsigned long);
  unsigned long data;
-
  struct tvec_t_base_s *base;
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 };
-
 #define TIMER_INITIALIZER(_function, _expires, _data) {   .function = (_function),   .expires = (_expires),   .data = (_data),   .base = &boot_tvec_bases,   }
-
 #define DEFINE_TIMER(_name, _function, _expires, _data)   struct timer_list _name =   TIMER_INITIALIZER(_function, _expires, _data)
-
 #define try_to_del_timer_sync(t) del_timer(t)
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define del_timer_sync(t) del_timer(t)
 #define del_singleshot_timer_sync(t) del_timer_sync(t)
-
 struct hrtimer;
-
 #endif
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */