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| author | Jianguo Wu <wujianguo@huawei.com> | 2013-12-18 17:08:54 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-01-29 05:10:42 -0800 |
| commit | 9a22404cf92f3c5ec2b2bf2554f0c92f021e77e9 (patch) | |
| tree | 4ae9248271149e2694cca636ac26c496a61935da | |
| parent | 7e99f2168460c70d96241da3e8ff749f05416222 (diff) | |
| download | lwn-9a22404cf92f3c5ec2b2bf2554f0c92f021e77e9.tar.gz lwn-9a22404cf92f3c5ec2b2bf2554f0c92f021e77e9.zip | |
mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully
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 3.4:
- adjust context
- s/num_poisoned_pages/mce_bad_pages/]
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>
| -rw-r--r-- | mm/memory-failure.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c index d86fb2057354..7e95698e4139 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1447,10 +1447,18 @@ static int soft_offline_huge_page(struct page *page, int flags) return ret; } done: - if (!PageHWPoison(hpage)) - atomic_long_add(1 << compound_trans_order(hpage), &mce_bad_pages); - set_page_hwpoison_huge_page(hpage); - dequeue_hwpoisoned_huge_page(hpage); + /* overcommit hugetlb page will be freed to buddy */ + if (PageHuge(hpage)) { + if (!PageHWPoison(hpage)) + atomic_long_add(1 << compound_trans_order(hpage), + &mce_bad_pages); + set_page_hwpoison_huge_page(hpage); + dequeue_hwpoisoned_huge_page(hpage); + } else { + SetPageHWPoison(page); + atomic_long_inc(&mce_bad_pages); + } + /* keep elevated page count for bad page */ return ret; } |