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authorChen Yucong <slaoub@gmail.com>2014-05-22 11:54:15 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-07 10:28:11 -0700
commit54a2ab1efaf5d35d68143a9c0f652955ad16eb82 (patch)
treef7ab75a6622580ead8e8aa860c96df367431a9b8 /mm
parent7c5a5a8a48bc22f7df51c1d78f595b411a447a0f (diff)
hwpoison, hugetlb: lock_page/unlock_page does not match for handling a free hugepage
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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/memory-failure.c15
1 files changed, 8 insertions, 7 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 90002ea43638..66586bb44c62 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1085,15 +1085,16 @@ 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);