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hwpoison, hugetlb: lock_page/unlock_page does not match for handling a free hugepage

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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>
Cc: <stable@vger.kernel.org>	[2.6.36+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Chen Yucong 2014-05-22 11:54:15 -07:00 committed by Linus Torvalds
parent 4b660a7f5c
commit b985194c8c
1 changed files with 8 additions and 7 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

15
mm/memory-failure.c
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@ -1081,15 +1081,16 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
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, &num_poisoned_pages);
return 0;
if (PageHWPoison(hpage)) {
if ((hwpoison_filter(p) && TestClearPageHWPoison(p))
|| (p != hpage && TestSetPageHWPoison(hpage))) {
atomic_long_sub(nr_pages, &num_poisoned_pages);
unlock_page(hpage);
return 0;
}
}
set_page_hwpoison_huge_page(hpage);
res = dequeue_hwpoisoned_huge_page(hpage);