Re: [PATCH 2.6] clean-up: fixes "comparison between signed

From: Petr Vandrovec
Date: Mon Dec 06 2004 - 20:04:11 EST


On Tue, Dec 07, 2004 at 12:09:05AM +0100, Jesper Juhl wrote:
> On Mon, 6 Dec 2004, Petr Vandrovec wrote:
> > Correct is (if any fix is needed at all) typecast regs->esp to unsigned
> > long,
>
> That would have been my suggestion as well.
>
> >eventually with check that address is less than (unsigned long)-32,
> > as area at VA 0 is not going to grow "down" to 0xFFFFFxxx, even if you
> > nicely ask.
>
> you mean something like this - right?

Yes. Though I believe that we already take vma == NULL path when address is that big.
Petr Vandrovec

> Signed-off-by: Jesper Juhl <juhl-lkml@xxxxxx>
>
> diff -up linux-2.6.10-rc3-bk2-orig/arch/i386/mm/fault.c linux-2.6.10-rc3-bk2/arch/i386/mm/fault.c
> --- linux-2.6.10-rc3-bk2-orig/arch/i386/mm/fault.c 2004-12-06 22:24:16.000000000 +0100
> +++ linux-2.6.10-rc3-bk2/arch/i386/mm/fault.c 2004-12-07 00:04:33.000000000 +0100
> @@ -305,7 +305,7 @@ fastcall void do_page_fault(struct pt_re
> * pusha) doing post-decrement on the stack and that
> * doesn't show up until later..
> */
> - if (address + 32 < regs->esp)
> + if (address + 32 < (unsigned long)regs->esp || address >= (~0UL - 32))
> goto bad_area;
> }
> if (expand_stack(vma, address))
>
>
>
-
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