[PATCH 3.4 04/12] mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully
3.4-stable review patch. If anyone has any objections, please let me know. -- From: Jianguo Wu 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 0058 IP: [] dequeue_hwpoisoned_huge_page+0x131/0x1d0 PGD c23762067 PUD c24be2067 PMD 0 Oops: [#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 Tested-by: Naoya Horiguchi Reviewed-by: Naoya Horiguchi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/memory-failure.c | 16 1 file changed, 12 insertions(+), 4 deletions(-) --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1447,10 +1447,18 @@ static int soft_offline_huge_page(struct return ret; } done: - if (!PageHWPoison(hpage)) - atomic_long_add(1 << compound_trans_order(hpage), _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), + _bad_pages); + set_page_hwpoison_huge_page(hpage); + dequeue_hwpoisoned_huge_page(hpage); + } else { + SetPageHWPoison(page); + atomic_long_inc(_bad_pages); + } + /* keep elevated page count for bad page */ return ret; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 3.4 04/12] mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully
3.4-stable review patch. If anyone has any objections, please let me know. -- From: Jianguo Wu wujian...@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 0058 IP: [81163761] dequeue_hwpoisoned_huge_page+0x131/0x1d0 PGD c23762067 PUD c24be2067 PMD 0 Oops: [#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 wujian...@huawei.com Tested-by: Naoya Horiguchi n-horigu...@ah.jp.nec.com Reviewed-by: Naoya Horiguchi n-horigu...@ah.jp.nec.com Signed-off-by: Andrew Morton a...@linux-foundation.org Signed-off-by: Linus Torvalds torva...@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gre...@linuxfoundation.org --- mm/memory-failure.c | 16 1 file changed, 12 insertions(+), 4 deletions(-) --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1447,10 +1447,18 @@ static int soft_offline_huge_page(struct 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; } -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/