linux-kernel - Re: [PATCH 01/18] mm, hugetlb: protect reserved pages when softofflining requests the pages

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAJd=RBCUJg5GJEQ2_heCt8S9LZzedGLbvYvivFkmvfMChPqaCg@mail.gmail.com>
Date:	Mon, 29 Jul 2013 15:24:46 +0800
From:	Hillf Danton <dhillf@...il.com>
To:	Joonsoo Kim <iamjoonsoo.kim@....com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Rik van Riel <riel@...hat.com>, Mel Gorman <mgorman@...e.de>,
	Michal Hocko <mhocko@...e.cz>,
	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Hugh Dickins <hughd@...gle.com>,
	Davidlohr Bueso <davidlohr.bueso@...com>,
	David Gibson <david@...son.dropbear.id.au>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, Joonsoo Kim <js1304@...il.com>,
	Wanpeng Li <liwanp@...ux.vnet.ibm.com>,
	Naoya Horiguchi <n-horiguchi@...jp.nec.com>
Subject: Re: [PATCH 01/18] mm, hugetlb: protect reserved pages when
 softofflining requests the pages

On Mon, Jul 29, 2013 at 1:31 PM, Joonsoo Kim <iamjoonsoo.kim@....com> wrote:
> alloc_huge_page_node() use dequeue_huge_page_node() without
> any validation check, so it can steal reserved page unconditionally.

Well, why is it illegal to use reserved page here?

> To fix it, check the number of free_huge_page in alloc_huge_page_node().
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@....com>
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 6782b41..d971233 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -935,10 +935,11 @@ static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
>   */
>  struct page *alloc_huge_page_node(struct hstate *h, int nid)
>  {
> -       struct page *page;
> +       struct page *page = NULL;
>
>         spin_lock(&hugetlb_lock);
> -       page = dequeue_huge_page_node(h, nid);
> +       if (h->free_huge_pages - h->resv_huge_pages > 0)
> +               page = dequeue_huge_page_node(h, nid);
>         spin_unlock(&hugetlb_lock);
>
>         if (!page)
> --
> 1.7.9.5
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/