Hi Greg, Please queue this for 3.10 stable kernel. I adjust context and can be applied to 3.10 stable clean.
---- From: Jianguo Wu <[email protected]> Date: Wed, 18 Dec 2013 17:08:54 -0800 Subject: [PATCH] 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. Signed-off-by: Jianguo Wu <[email protected]> Tested-by: Naoya Horiguchi <[email protected]> Reviewed-by: Naoya Horiguchi <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> [wujg: backport to 3.10: - adjust context] --- mm/memory-failure.c | 14 ++++++++++---- 1 files changed, 10 insertions(+), 4 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 6a7f9ca..7e3601c 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1499,10 +1499,16 @@ static int soft_offline_huge_page(struct page *page, int flags) 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; -- 1.7.7 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
