scripts: Fix the inclusion order in modpost
authorVincenzo Frascino <vincenzo.frascino@arm.com>
Fri, 20 Mar 2020 14:53:41 +0000 (14:53 +0000)
committerThomas Gleixner <tglx@linutronix.de>
Sat, 21 Mar 2020 14:24:00 +0000 (15:24 +0100)
In the process of creating the source file of a module modpost injects a
set of includes that are not required if the compilation unit is
statically built into the kernel.

The order of inclusion of the headers can cause redefinition problems
(e.g.):

   In file included from include/linux/elf.h:5:0,
                    from include/linux/module.h:18,
                    from crypto/arc4.mod.c:2:
    #define ELF_OSABI  ELFOSABI_LINUX

   In file included from include/linux/elfnote.h:62:0,
                    from include/linux/build-salt.h:4,
                    from crypto/arc4.mod.c:1:
   include/uapi/linux/elf.h:363:0: note: this is the location of
   the previous definition
    #define ELF_OSABI ELFOSABI_NONE

The issue was exposed during the development of the series [1].

[1] https://lore.kernel.org/lkml/20200306133242.26279-1-vincenzo.frascino@arm.com/

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Link: https://lkml.kernel.org/r/20200320145351.32292-17-vincenzo.frascino@arm.com
scripts/mod/modpost.c

index 7edfdb2f4497ac471b116733c48165699a015f0c..0f354b1ee2aa5b5fd854f6a15f7027581f0950f8 100644 (file)
@@ -2251,8 +2251,12 @@ static int check_modname_len(struct module *mod)
  **/
 static void add_header(struct buffer *b, struct module *mod)
 {
-       buf_printf(b, "#include <linux/build-salt.h>\n");
        buf_printf(b, "#include <linux/module.h>\n");
+       /*
+        * Include build-salt.h after module.h in order to
+        * inherit the definitions.
+        */
+       buf_printf(b, "#include <linux/build-salt.h>\n");
        buf_printf(b, "#include <linux/vermagic.h>\n");
        buf_printf(b, "#include <linux/compiler.h>\n");
        buf_printf(b, "\n");