On Mon, Aug 10, 2015 at 02:32:31PM +0800, Wanpeng Li wrote: > Hwpoison injection takes a refcount of target page and another refcount > of head page of THP if the target page is the tail page of a THP. However, > current code doesn't release the refcount of head page if the THP is not > supported to be injected wrt hwpoison filter. > > Fix it by reducing the refcount of head page if the target page is the tail > page of a THP and it is not supported to be injected. > > Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx> > --- > mm/hwpoison-inject.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c > index 5015679..c343a45 100644 > --- a/mm/hwpoison-inject.c > +++ b/mm/hwpoison-inject.c > @@ -56,6 +56,8 @@ inject: > return memory_failure(pfn, 18, MF_COUNT_INCREASED); > put_out: > put_page(p); > + if (p != hpage) > + put_page(hpage); Yes, we need this when we inject to a thp tail page and "goto put_out" is called. But it seems that this code can be called also when injecting error to a hugetlb tail page and hwpoison_filter() returns non-zero, which is not expected. Unfortunately simply doing like below + if (!PageHuge(p) && p != hpage) + put_page(hpage); doesn't work, because exisiting put_page(p) can release refcount of hugetlb tail page, while get_hwpoison_page() takes refcount of hugetlb head page. So I feel that we need put_hwpoison_page() to properly release the refcount taken by memory error handlers. I'll post some patch(es) to address this problem this week. Thanks, Naoya Horiguchi -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href