[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <CAHz2CGXc6=r_D1L6nUTj7A_bbX7GeUFb5+0TZWh55UUA6hiQ7w@mail.gmail.com>
Date: Tue, 26 Jan 2016 14:39:26 +0800
From: Jianyu Zhan <nasa4836@...il.com>
To: Laura Abbott <labbott@...oraproject.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>, Vlastimil Babka <vbabka@...e.cz>,
Michal Hocko <mhocko@...e.com>, "linux-mm@...ck.org" <linux-mm@...ck.org>,
LKML <linux-kernel@...r.kernel.org>, kernel-hardening@...ts.openwall.com,
Kees Cook <keescook@...omium.org>
Subject: Re: [RFC][PATCH 2/3] mm/page_poison.c: Enable PAGE_POISONING as a
separate option
On Tue, Jan 26, 2016 at 12:55 AM, Laura Abbott
<labbott@...oraproject.org> wrote:
> --- a/mm/debug-pagealloc.c
> +++ b/mm/debug-pagealloc.c
> @@ -8,11 +8,5 @@
>
> void __kernel_map_pages(struct page *page, int numpages, int enable)
> {
> - if (!page_poisoning_enabled())
> - return;
> -
> - if (enable)
> - unpoison_pages(page, numpages);
> - else
> - poison_pages(page, numpages);
> + kernel_poison_pages(page, numpages, enable);
> }
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 63358d9..c733421 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -1002,6 +1002,7 @@ static bool free_pages_prepare(struct page *page, unsigned int order)
> PAGE_SIZE << order);
> }
> arch_free_page(page, order);
> + kernel_poison_pages(page, 1 << order, 0);
> kernel_map_pages(page, 1 << order, 0);
>
> return true;
> @@ -1396,6 +1397,7 @@ static int prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
> set_page_refcounted(page);
>
> arch_alloc_page(page, order);
> + kernel_poison_pages(page, 1 << order, 1);
> kernel_map_pages(page, 1 << order, 1);
> kasan_alloc_pages(page, order);
>
kernel_map_pages() will fall back to page poisoning scheme for
!ARCH_SUPPORTS_DEBUG_PAGEALLOC.
IIUC, calling kernel_poison_pages() before kernel_map_pages() will be
equivalent to call kernel_poison_pages()
twice?!
Thanks,
Jianyu Zhan
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
