mm/hwpoison: fix fail isolate hugetlbfs page w/ refcount held

Hugetlbfs pages will get a refcount in get_any_page() or
madvise_hwpoison() if soft offlining through madvise.  The refcount which
is held by the soft offline path should be released if we fail to isolate
hugetlbfs pages.

Fix it by reducing the refcount for both isolation success and failure.

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>	[3.9+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 7 deletions

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 81c20a7c9fa7..dba52ee31bd4 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1569,13 +1569,12 @@ static int soft_offline_huge_page(struct page *page, int flags)
         unlock_page(hpage);
 
         ret = isolate_huge_page(hpage, &pagelist);
-        if (ret) {
-                /*
-                 * get_any_page() and isolate_huge_page() takes a refcount each,
-                 * so need to drop one here.
-                 */
-                put_page(hpage);
-        } else {
+        /*
+         * get_any_page() and isolate_huge_page() takes a refcount each,
+         * so need to drop one here.
+         */
+        put_page(hpage);
+        if (!ret) {
                 pr_info("soft offline: %#lx hugepage failed to isolate\n", pfn);
                 return -EBUSY;
         }