On Wed, Apr 13, 2011 at 19:41, Andrew Morton <[email protected]> wrote:
> On Wed, 13 Apr 2011 19:16:40 +0200 Geert Uytterhoeven <[email protected]>
> wrote:
>
>> On Wed, Apr 13, 2011 at 19:04, Andrew Morton <[email protected]>
>> wrote:
>> > On Wed, 13 Apr 2011 09:59:50 +0200 Geert Uytterhoeven
>> > <[email protected]> wrote:
>> >
>> >> CC stable for v2.6.38
>> >>
>> >> ..
>> >>
>> >> > 5520e89 ("brk: fix min_brk lower bound computation for COMPAT_BRK")
>> >> > tried
>> >> > to get the whole logic of brk randomization for legacy (libc5-based)
>> >> > applications finally right.
>> >> >
>> >> > It turns out that the way to detect whether brk has actually been
>> >> > randomized in the end or not introduced by that patch still doesn't work
>> >> > for those binaries, as reported by Geert.
>> >> >
>> >> > I don't like it, but currently see no better option than a bit flag in
>> >> > task_struct to catch the CONFIG_COMPAT_BRK && randomize_va_space == 2
>> >> > case.
>> >> >
>> >
>> > There's nothing in this changelog which tells us that the problem is
>> > serious enough to need fixing in -stable. If there had been, I'd have
>> > added cc:stable to the changelog myself.
>> >
>> > So. Why do we think this needs fixing in 2.6.38+?
>>
>> Because it's a regression on running (albeit very old) userspace binaries.
>>
>
> What is a regression? Please provide a description of the kernel behavior
/sbin/init from my old m68k ramdisk exists prematurely.
> both before and after this patch.
Before the patch:
| brk(0x80005c8e) = 0x80006000
After the patch:
| brk(0x80005c8e) = 0x80005c8e
Old libc5 considers brk() to have failed if the return value is not identical to
the requested value.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
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
_______________________________________________
stable mailing list
[email protected]
http://linux.kernel.org/mailman/listinfo/stable
