| From a49ecbcd7b0d5a1cda7d60e03df402dd0ef76ac8 Mon Sep 17 00:00:00 2001 |
| From: Jianguo Wu <wujianguo@huawei.com> |
| Date: Wed, 18 Dec 2013 17:08:54 -0800 |
| Subject: mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully |
| |
| From: Jianguo Wu <wujianguo@huawei.com> |
| |
| commit a49ecbcd7b0d5a1cda7d60e03df402dd0ef76ac8 upstream. |
| |
| 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(). |
| |
| BUG: unable to handle kernel NULL pointer dereference at 0000000000000058 |
| IP: [<ffffffff81163761>] dequeue_hwpoisoned_huge_page+0x131/0x1d0 |
| PGD c23762067 PUD c24be2067 PMD 0 |
| Oops: 0000 [#1] SMP |
| |
| So check PageHuge(page) after call migrate_pages() successfully. |
| |
| [wujg: backport to 3.10: |
| - adjust context] |
| |
| Signed-off-by: Jianguo Wu <wujianguo@huawei.com> |
| Tested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> |
| Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| mm/memory-failure.c | 14 ++++++++++---- |
| 1 file changed, 10 insertions(+), 4 deletions(-) |
| |
| --- a/mm/memory-failure.c |
| +++ b/mm/memory-failure.c |
| @@ -1499,10 +1499,16 @@ static int soft_offline_huge_page(struct |
| pr_info("soft offline: %#lx: migration failed %d, type %lx\n", |
| pfn, ret, page->flags); |
| } else { |
| - set_page_hwpoison_huge_page(hpage); |
| - dequeue_hwpoisoned_huge_page(hpage); |
| - atomic_long_add(1 << compound_trans_order(hpage), |
| - &num_poisoned_pages); |
| + /* overcommit hugetlb page will be freed to buddy */ |
| + if (PageHuge(page)) { |
| + set_page_hwpoison_huge_page(hpage); |
| + dequeue_hwpoisoned_huge_page(hpage); |
| + atomic_long_add(1 << compound_order(hpage), |
| + &num_poisoned_pages); |
| + } else { |
| + SetPageHWPoison(page); |
| + atomic_long_inc(&num_poisoned_pages); |
| + } |
| } |
| /* keep elevated page count for bad page */ |
| return ret; |
