Re: [PATCH 1/3] module: deal with alignment issues in built-in module versions

Geert Uytterhoeven
2011-02-21T13:26:00Z

On Mon, Feb 21, 2011 at 08:49, Dmitry Torokhov <dtor@vmware.com> wrote:
> On Mon, Feb 21, 2011 at 08:38:46AM +0100, Geert Uytterhoeven wrote:
>> On Mon, Feb 21, 2011 at 05:00, Rusty Russell <rusty@rustcorp.com.au> wrote:
>> >> Except that .long is 32-bit on ppc64 :-( You need .llong for 64-bit.
>> >
>> > OK, all options suck.  Do we want the workaround or not?
>>
>> We can discuss about that until someone gets bitten by that.
>>
>> But please fix the "aligned(sizeof(void *))"-in-one-place-only issue.
>>
>
> How about this one then?

Works.

> From f0e0e10b58b22047e36e21a022abf5e86b5819c2 Mon Sep 17 00:00:00 2001
> From: Dmitry Torokhov <dtor@vmware.com>
> Date: Fri, 4 Feb 2011 13:30:10 -0800
> Subject: [PATCH] module: explicitly align module_version_attribute structure
>
> We force particular alignment when we generate attribute structures
> when generation MODULE_VERSION() data and we need to make sure that
> this alignment is followed when we iterate over these structures,
> otherwise we may crash on platforms whose natural alignment is not
> sizeof(void *), such as m68k.
>
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Signed-off-by: Dmitry Torokhov <dtor@vmware.com>

Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>

> ---
>  include/linux/module.h |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/include/linux/module.h b/include/linux/module.h
> index e7c6385..de5cd21 100644
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -62,7 +62,7 @@ struct module_version_attribute {
>        struct module_attribute mattr;
>        const char *module_name;
>        const char *version;
> -};
> +} __attribute__ ((__aligned__(sizeof(void *))));
>
>  struct module_kobject
>  {
> --
> 1.7.3.2

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds