| From | Ben Hutchings <> | Date | Sat, 07 Jun 2014 02:26:29 +0100 | Subject | [PATCH 3.2 85/92] hwpoison, hugetlb: lock_page/unlock_page does not match for handling a free hugepage |
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3.2.60-rc1 review patch. If anyone has any objections, please let me know.
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From: Chen Yucong <slaoub@gmail.com>
commit b985194c8c0a130ed155b71662e39f7eaea4876f upstream.
For handling a free hugepage in memory failure, the race will happen if another thread hwpoisoned this hugepage concurrently. So we need to check PageHWPoison instead of !PageHWPoison.
If hwpoison_filter(p) returns true or a race happens, then we need to unlock_page(hpage).
Signed-off-by: Chen Yucong <slaoub@gmail.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Tested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [bwh: Backported to 3.2: s/num_poisoned_pages/bad_mce_pages/] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- mm/memory-failure.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-)
--- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1033,15 +1033,16 @@ int __memory_failure(unsigned long pfn, return 0; } else if (PageHuge(hpage)) { /* - * Check "just unpoisoned", "filter hit", and - * "race with other subpage." + * Check "filter hit" and "race with other subpage." */ lock_page(hpage); - if (!PageHWPoison(hpage) - || (hwpoison_filter(p) && TestClearPageHWPoison(p)) - || (p != hpage && TestSetPageHWPoison(hpage))) { - atomic_long_sub(nr_pages, &mce_bad_pages); - return 0; + if (PageHWPoison(hpage)) { + if ((hwpoison_filter(p) && TestClearPageHWPoison(p)) + || (p != hpage && TestSetPageHWPoison(hpage))) { + atomic_long_sub(nr_pages, &mce_bad_pages); + unlock_page(hpage); + return 0; + } } set_page_hwpoison_huge_page(hpage); res = dequeue_hwpoisoned_huge_page(hpage);
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