linux-kernel - Re: [PATCH 1/2] mm/hwpoison-inject: fix refcounting in no-injection case

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Date:	Thu, 23 Apr 2015 19:42:14 -0500
From:	Dean Nelson <dnelson@...hat.com>
To:	Naoya Horiguchi <n-horiguchi@...jp.nec.com>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	Andi Kleen <andi@...stfloor.org>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] mm/hwpoison-inject: fix refcounting in no-injection
 case

On 04/16/2015 09:08 PM, Naoya Horiguchi wrote:
> Hwpoison injection via debugfs:hwpoison/corrupt-pfn takes a refcount of
> the target page. But current code doesn't release it if the target page
> is not supposed to be injected, which results in memory leak.
> This patch simply adds the refcount releasing code.
> 
> Signed-off-by: Naoya Horiguchi <n-horiguchi@...jp.nec.com>

Acked-by: Dean Nelson <dnelson@...hat.com>


> ---
>   mm/hwpoison-inject.c | 7 +++++--
>   1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git v4.0.orig/mm/hwpoison-inject.c v4.0/mm/hwpoison-inject.c
> index 329caf56df22..2b3f933e3282 100644
> --- v4.0.orig/mm/hwpoison-inject.c
> +++ v4.0/mm/hwpoison-inject.c
> @@ -40,7 +40,7 @@ static int hwpoison_inject(void *data, u64 val)
>   	 * This implies unable to support non-LRU pages.
>   	 */
>   	if (!PageLRU(p) && !PageHuge(p))
> -		return 0;
> +		goto put_out;
>   
>   	/*
>   	 * do a racy check with elevated page count, to make sure PG_hwpoison
> @@ -52,11 +52,14 @@ static int hwpoison_inject(void *data, u64 val)
>   	err = hwpoison_filter(hpage);
>   	unlock_page(hpage);
>   	if (err)
> -		return 0;
> +		goto put_out;
>   
>   inject:
>   	pr_info("Injecting memory failure at pfn %#lx\n", pfn);
>   	return memory_failure(pfn, 18, MF_COUNT_INCREASED);
> +put_out:
> +	put_page(hpage);
> +	return 0;
>   }
>   
>   static int hwpoison_unpoison(void *data, u64 val)
> 

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