Re: [PATCH 3.2 056/185] mm: ensure get_unmapped_area() returns higher address than mmap_min_addr

Akira Takeuchi
2014-01-06T10:19:37Z

On Fri, 03 Jan 2014 04:26:43 +0000
Ben Hutchings <ben@decadent.org.uk> wrote:

> On Sun, 2013-12-29 at 03:08 +0100, Ben Hutchings wrote:
> > 3.2.54-rc1 review patch. If anyone has any objections, please let me know.
> >
> > ------------------
> >
> > From: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>
> >
> > commit 2afc745f3e3079ab16c826be4860da2529054dd2 upstream.
> [...]
> > [bwh: Backported to 3.2:
> > As we do not have vm_unmapped_area(), make arch_get_unmapped_area_topdown()
> > calculate the lower limit for the new area's end address and then compare
> > addresses with this instead of with len. In the process, fix an off-by-one
> > error which could result in returning 0 if mm->mmap_base == len.]
>
> I'm dropping this as I have no good way to test the backport (it's not
> used on x86) and I didn't get any confirmation that it's right.

I'm sorry for delayed reply.

Your backport seems right.
Additionally, I've confirmed the problem is resolved by your backport patch.

Best regards,
Akira Takeuchi