From: Michal Hocko <mhocko@suse.com>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Linux-MM <linux-mm@kvack.org>,
lkml <linux-kernel@vger.kernel.org>,
Muchun Song <songmuchun@bytedance.com>,
Oscar Salvador <osalvador@suse.de>,
David Hildenbrand <david@redhat.com>,
Naoya Horiguchi <naoya.horiguchi@nec.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] mm: hugetlb: fix dissolve_free_huge_page use of tail/head page
Date: Mon, 31 May 2021 08:48:58 +0200 [thread overview]
Message-ID: <YLSG2vUTv+QSAw8a@dhcp22.suse.cz> (raw)
In-Reply-To: <20210527231225.226987-1-mike.kravetz@oracle.com>
On Thu 27-05-21 16:12:25, Mike Kravetz wrote:
> The routine dissolve_free_huge_page can be passed the tail page of a
> hugetlb page. The tail page is incorrectly passed on to the routines
> alloc_huge_page_vmemmap and add_hugetlb_page which expect a hugetlb
> head page.
>
> Operating on a tail page instead of head page could result in addressing
> exceptions or vmemmap corruption.
>
> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> The code with this issue is only in mmotm (and next). Specifically
> mm: hugetlb: alloc the vmemmap pages associated with each HugeTLB page
> Andrew, I assume you will fix in your tree.
Yes, folding this in sounds like the best way forward.
>
> mm/hugetlb.c | 4 ++--
> scripts/rust-version.sh | 0
> 2 files changed, 2 insertions(+), 2 deletions(-)
> mode change 100644 => 100755 scripts/rust-version.sh
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 69a4b551c157..d2461c1f32dd 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1954,7 +1954,7 @@ int dissolve_free_huge_page(struct page *page)
> * Attempt to allocate vmemmmap here so that we can take
> * appropriate action on failure.
> */
> - rc = alloc_huge_page_vmemmap(h, page);
> + rc = alloc_huge_page_vmemmap(h, head);
> if (!rc) {
> /*
> * Move PageHWPoison flag from head page to the raw
> @@ -1968,7 +1968,7 @@ int dissolve_free_huge_page(struct page *page)
> update_and_free_page(h, head, false);
> } else {
> spin_lock_irq(&hugetlb_lock);
> - add_hugetlb_page(h, page, false);
> + add_hugetlb_page(h, head, false);
> h->max_huge_pages++;
> spin_unlock_irq(&hugetlb_lock);
> }
> diff --git a/scripts/rust-version.sh b/scripts/rust-version.sh
> old mode 100644
> new mode 100755
> --
> 2.31.1
>
--
Michal Hocko
SUSE Labs
prev parent reply other threads:[~2021-05-31 6:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-27 23:12 [PATCH] mm: hugetlb: fix dissolve_free_huge_page use of tail/head page Mike Kravetz
2021-05-28 1:18 ` kernel test robot
2021-05-28 2:42 ` [External] " Muchun Song
2021-05-28 7:30 ` Oscar Salvador
2021-05-31 6:48 ` Michal Hocko [this message]
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