| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.12 05/82] mm/memory-failure.c: move refcount only in !MF_COUNT_INCREASED | Date | Thu, 20 Feb 2014 15:51:48 -0800 |
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3.12-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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- mm/memory-failure.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -945,8 +945,10 @@ static int hwpoison_user_mappings(struct * 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;
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