| From | Luis Henriques <> | Subject | [PATCH 3.11 094/121] mm/memory-failure.c: move refcount only in !MF_COUNT_INCREASED | Date | Fri, 21 Feb 2014 12:48:38 +0000 |
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3.11.10.5 -stable review patch. If anyone has any objections, please let me know.
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From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
commit 8d547ff4ac5927245e0833ac18528f939da0ee0e upstream.
mce-test detected a test failure when injecting error to a thp tail page. This is because we take page refcount of the tail page in madvise_hwpoison() while the fix in commit a3e0f9e47d5e ("mm/memory-failure.c: transfer page count from head page to tail page after split thp") assumes that we always take refcount on the head page.
When a real memory error happens we take refcount on the head page where memory_failure() is called without MF_COUNT_INCREASED set, so it seems to me that testing memory error on thp tail page using madvise makes little sense.
This patch cancels moving refcount in !MF_COUNT_INCREASED for valid testing.
[akpm@linux-foundation.org: s/&&/&/] Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com> Cc: Chen Gong <gong.chen@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- mm/memory-failure.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c index bfee485..a869081 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -943,8 +943,10 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn, * to it. Similarly, page lock is shifted. */ if (hpage != p) { - put_page(hpage); - get_page(p); + if (!(flags & MF_COUNT_INCREASED)) { + put_page(hpage); + get_page(p); + } lock_page(p); unlock_page(hpage); *hpagep = p; -- 1.9.0
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