# Resending due to sending failure. Sorry if you received twice.
---
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.
Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 3.9+: a3e0f9e47d5e
---
mm/memory-failure.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git v3.14-rc1.orig/mm/memory-failure.c v3.14-rc1/mm/memory-failure.c
index ab55d489eb05..16886ddb6ab4 100644
--- v3.14-rc1.orig/mm/memory-failure.c
+++ v3.14-rc1/mm/memory-failure.c
@@ -1042,8 +1042,10 @@ 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;
--
1.8.5.3
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