[PATCH] powerpc/mm: remove hack in mmap randomize layout

Dan McGee dpmcgee at gmail.com
Tue Oct 18 09:43:11 EST 2011


On Mon, Oct 17, 2011 at 4:51 PM, David Miller <davem at davemloft.net> wrote:
> From: Dan McGee <dpmcgee at gmail.com>
> Date: Mon, 17 Oct 2011 15:17:36 -0500
>
>> Since commit 8a0a9bd4db63bc45e301, this comment in mmap_rnd() does not
>> hold true as the value returned by get_random_int() will in fact be
>> different every single call. Remove the comment and simplify the code
>> back to its original desired form.
>>
>> This reverts commit a5adc91a4b44b5d1 which is no longer necessary.
>>
>> Signed-off-by: Dan McGee <dpmcgee at gmail.com>
>
> Can you please fix up all the other architectures which use the same
> logic, because they have simply copied over what powerpc does?
>
> At a minimum, Sparc has two such locations.
Aha, I wasn't aware this was also being done elsewhere as there was no
comment to tip me off. I found the one in
arch/sparc/kernel/sys_sparc_64.c (mmap_rnd) and have fixed that
locally and will resend, but I'm not seeing get_random_int() in use
anywhere else in that architecture so I'm not quite sure where your
second mentioned location is- or did you just mean the two calls 2
lines apart in mmap_rnd()?

I also did a quick glance over every other usage and didn't seen any
other architectures doing anything funky, even in a slightly different
way.

-Dan


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