lkml.org 
[lkml]   [2013]   [Dec]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfull
(Cced: Chen Gong)

I confirmed that this patch fixes the reported bug.
And I'll send a test patch for mce-test later privately.

Tested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>

Jianguo, could you put "Cc: stable@vger.kernel.org"
in patch description?
And please fix a typo in subject line.

Thanks,
Naoya Horiguchi

On Thu, Dec 12, 2013 at 09:14:05PM +0800, Jianguo Wu wrote:
> After a successful hugetlb page migration by soft offline, the source page
> will either be freed into hugepage_freelists or buddy(over-commit page). If page is in
> buddy, page_hstate(page) will be NULL. It will hit a NULL pointer
> dereference in dequeue_hwpoisoned_huge_page().
>
> [ 890.677918] BUG: unable to handle kernel NULL pointer dereference at
> 0000000000000058
> [ 890.685741] IP: [<ffffffff81163761>]
> dequeue_hwpoisoned_huge_page+0x131/0x1d0
> [ 890.692861] PGD c23762067 PUD c24be2067 PMD 0
> [ 890.697314] Oops: 0000 [#1] SMP
>
> So check PageHuge(page) after call migrate_pages() successfull.
>
> Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
> ---
> mm/memory-failure.c | 19 ++++++++++++++-----
> 1 file changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index b7c1716..e5567f2 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1471,7 +1471,8 @@ static int get_any_page(struct page *page, unsigned long pfn, int flags)
>
> static int soft_offline_huge_page(struct page *page, int flags)
> {
> - int ret;
> + int ret, i;
> + unsigned long nr_pages;
> unsigned long pfn = page_to_pfn(page);
> struct page *hpage = compound_head(page);
> LIST_HEAD(pagelist);
> @@ -1489,6 +1490,8 @@ static int soft_offline_huge_page(struct page *page, int flags)
> }
> unlock_page(hpage);
>
> + nr_pages = 1 << compound_order(hpage);
> +
> /* Keep page count to indicate a given hugepage is isolated. */
> list_move(&hpage->lru, &pagelist);
> ret = migrate_pages(&pagelist, new_page, MPOL_MF_MOVE_ALL,
> @@ -1505,10 +1508,16 @@ static int soft_offline_huge_page(struct page *page, int flags)
> if (ret > 0)
> ret = -EIO;
> } else {
> - set_page_hwpoison_huge_page(hpage);
> - dequeue_hwpoisoned_huge_page(hpage);
> - atomic_long_add(1 << compound_order(hpage),
> - &num_poisoned_pages);
> + /* over-commit hugetlb page will be freed into buddy */
> + if (PageHuge(page)) {
> + set_page_hwpoison_huge_page(hpage);
> + dequeue_hwpoisoned_huge_page(hpage);
> + } else {
> + for (i = 0; i < nr_pages; i++)
> + SetPageHWPoison(hpage + i);
> + }
> +
> + atomic_long_add(nr_pages, &num_poisoned_pages);
> }
> return ret;
> }
> --
> 1.8.2.2
>
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
>


\
 
 \ /
  Last update: 2013-12-12 19:41    [W:0.039 / U:0.772 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site