On Mon, Aug 10, 2015 at 04:54:39PM +0800, Wanpeng Li wrote: > On 8/10/15 4:35 PM, Naoya Horiguchi wrote: > >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...@hotmail.com> > >>--- > >> 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. > > Good point. I think I will continue to do it and will post it out soon. :)
Great, thank you :) Naoya-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
