From: Jianguo Wu <[email protected]> Subject: mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully
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() 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]> --- mm/memory-failure.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff -puN mm/memory-failure.c~mm-memory-failurec-recheck-pagehuge-after-hugetlb-page-migrate-successfully mm/memory-failure.c --- a/mm/memory-failure.c~mm-memory-failurec-recheck-pagehuge-after-hugetlb-page-migrate-successfully +++ a/mm/memory-failure.c @@ -1505,10 +1505,16 @@ static int soft_offline_huge_page(struct 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); + /* 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); + } } return ret; } _ -- 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
