diff --git a/libc/kernel/common/linux/bitmap.h b/libc/kernel/common/linux/bitmap.h
index 246d158..c43959a 100644
--- a/libc/kernel/common/linux/bitmap.h
+++ b/libc/kernel/common/linux/bitmap.h
@@ -7,18 +7,23 @@
  ***   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_BITMAP_H
 #define __LINUX_BITMAP_H
-
 #ifndef __ASSEMBLY__
-
 #include <linux/types.h>
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #include <linux/bitops.h>
 #include <linux/string.h>
-
 #define BITMAP_LAST_WORD_MASK(nbits)  (   ((nbits) % BITS_PER_LONG) ?   (1UL<<((nbits) % BITS_PER_LONG))-1 : ~0UL  )
-
 #endif
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #endif