linux-kernel - Re: [PATCHv2 1/2] x86/mm: Do not allow non-MAP_FIXED mapping across DEFAULT_MAP

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Date:   Wed, 15 Nov 2017 15:23:32 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     "Kirill A. Shutemov" <kirill@...temov.name>
cc:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Ingo Molnar <mingo@...hat.com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Andy Lutomirski <luto@...capital.net>,
        Nicholas Piggin <npiggin@...il.com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCHv2 1/2] x86/mm: Do not allow non-MAP_FIXED mapping across
 DEFAULT_MAP_WINDOW border

On Wed, 15 Nov 2017, Kirill A. Shutemov wrote:
> On Wed, Nov 15, 2017 at 05:04:26PM +0300, Kirill A. Shutemov wrote:
>  	/* requesting a specific address */
>  	if (addr) {
> -		addr = PAGE_ALIGN(addr);
> +		addr &= PAGE_MASK;
>  		if (!mmap_address_hint_valid(addr, len))
>  			goto get_unmapped_area;
>  
> diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
> index 92db903c3dad..00b296617ca4 100644
> --- a/arch/x86/mm/hugetlbpage.c
> +++ b/arch/x86/mm/hugetlbpage.c
> @@ -166,7 +166,7 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
>  	}
>  
>  	if (addr) {
> -		addr = ALIGN(addr, huge_page_size(h));
> +		addr &= huge_page_mask(h);
>  		if (!mmap_address_hint_valid(addr, len))
>  			goto get_unmapped_area;

That should work. Care to pickup my variant, make the fixups and resend
along with the selftest which covers both normal and huge mappings?

Thanks,

	tglx