Re: [PATCHv2 1/2] x86/mm: Do not allow non-MAP_FIXED mapping across DEFAULT_MAP_WINDOW border

[Kirill A. Shutemov]

On Tue, Nov 14, 2017 at 05:01:50PM +0100, Thomas Gleixner wrote:
> @@ -198,11 +199,14 @@ arch_get_unmapped_area_topdown(struct fi
>  	/* requesting a specific address */
>  	if (addr) {
>  		addr = PAGE_ALIGN(addr);
> +		if (!mmap_address_hint_valid(addr, len))
> +			goto get_unmapped_area;
> +

Here and in hugetlb_get_unmapped_area(), we should align the addr after
the check, not before. Otherwise the alignment itself can bring us over
the borderline as we align up.

-- 
 Kirill A. Shutemov