linux-kernel - [PATCH v2 2/2] mm/hwpoison: fix fail isolate hugetlbfs page w/ refcount held

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Date:	Fri, 7 Aug 2015 18:16:42 +0800
From:	Wanpeng Li <wanpeng.li@...mail.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
CC:	Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
	Tony Luck <tony.luck@...el.com>,
	Andi Kleen <andi@...stfloor.org>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, Wanpeng Li <wanpeng.li@...mail.com>,
	<stable@...r.kernel.org>
Subject: [PATCH v2 2/2] 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 offline through madvise. The refcount which held by soft offline 
path should be released if fail to isolate hugetlbfs pages. This patch fix 
it by reducing a refcount for both isolate successfully and failure.

Cc: <stable@...r.kernel.org> # 3.9+
Signed-off-by: Wanpeng Li <wanpeng.li@...mail.com> 
---
 mm/memory-failure.c |   13 ++++++-------
 1 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 001f1ba..8077b1c 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1557,13 +1557,12 @@ 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;
 	}
-- 
1.7.1

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