From: Wanpeng Li <wanpeng.li@hotmail.com>
Date: Fri, 14 Aug 2015 22:34:59 +0000 (-0700)
Subject: mm/hwpoison: fix fail isolate hugetlbfs page w/ refcount held
X-Git-Tag: v4.1.7~76
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=d73eba8c9e33c0d5b487c04a0fc498432f074fea;p=users%2Fjedix%2Flinux-maple.git

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

commit 036138080a4376e5f3e5d0cca8ac99084c5cf06e upstream.

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>
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>
---

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 79fa29332fa39..9f48145c884fc 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1589,13 +1589,12 @@ 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;
 	}