linux-kernel - Re: [PATCH 1/6] mm, hwpoison: fix page refcnt leaking in try_memory_failure

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Message-ID: <20220819052003.GA613144@hori.linux.bs1.fc.nec.co.jp>
Date:   Fri, 19 Aug 2022 05:20:23 +0000
From:   HORIGUCHI NAOYA(堀口　直也) 
        <naoya.horiguchi@....com>
To:     Miaohe Lin <linmiaohe@...wei.com>
CC:     "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/6] mm, hwpoison: fix page refcnt leaking in
 try_memory_failure_hugetlb()

On Thu, Aug 18, 2022 at 09:00:11PM +0800, Miaohe Lin wrote:
> When hwpoison_filter() refuses to hwpoison a hugetlb page, the refcnt of
> the page would have been incremented if res == 1. Using put_page() to fix
> the refcnt leaking in this case.
> 
> Fixes: 405ce051236c ("mm/hwpoison: fix race between hugetlb free/demotion and memory_failure_hugetlb()")
> Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>

Looks good to me, thank you.

Acked-by: Naoya Horiguchi <naoya.horiguchi@....com>

> ---
>  mm/memory-failure.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index e48f6f6a259d..22840cd5fe59 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1860,8 +1860,10 @@ static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb
>  
>  	if (hwpoison_filter(p)) {
>  		hugetlb_clear_page_hwpoison(head);
> -		res = -EOPNOTSUPP;
> -		goto out;
> +		unlock_page(head);
> +		if (res == 1)
> +			put_page(head);
> +		return -EOPNOTSUPP;
>  	}
>  
>  	/*
> -- 
> 2.23.0