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

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

[Wanpeng Li]

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@vger.kernel.org> # 3.9+
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.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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Re: [PATCH v2 2/2] mm/hwpoison: fix fail isolate hugetlbfs page w/ refcount held

[Naoya Horiguchi]

On Fri, Aug 07, 2015 at 06:16:42PM +0800, Wanpeng Li wrote:
> 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@vger.kernel.org> # 3.9+
> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> 

Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.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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