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Subject: Re: [PATCH stable-5.10] mm/memory-failure: fix an incorrect use of
 tail pages
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
References: <20240307124841.2838010-1-liushixin2@huawei.com>
CC: Matthew Wilcox <willy@infradead.org>, Andrew Morton
	<akpm@linux-foundation.org>, Sasha Levin <sashal@kernel.org>, Dan Williams
	<dan.j.williams@intel.com>, Naoya Horiguchi <naoya.horiguchi@nec.com>,
	<linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
	<stable@vger.kernel.org>
From: Liu Shixin <liushixin2@huawei.com>
Message-ID: <cb1cba51-69a9-846f-250c-4740938eb10e@huawei.com>
Date: Mon, 11 Mar 2024 09:51:56 +0800
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Hi, Greg,

There is a bugfix for 5.10-stable, 5.4-stable, 4.19-stable. Introduced when backport

commit c79c5a0a00a9 ("mm/memory-failure: check the mapcount of the precise page").

[1]: https://lore.kernel.org/stable/20240307124841.2838010-1-liushixin2@huawei.com/

[2]: https://lore.kernel.org/stable/20240307125053.2847205-1-liushixin2@huawei.com/

[3]: https://lore.kernel.org/stable/20240307125150.2849068-1-liushixin2@huawei.com/


Thanks,


On 2024/3/7 20:48, Liu Shixin wrote:
> When backport commit c79c5a0a00a9 to 5.10-stable, there is a mistake change.
> The head page instead of tail page should be passed to try_to_unmap(),
> otherwise unmap will failed as follows.
>
>  Memory failure: 0x121c10: failed to unmap page (mapcount=1)
>  Memory failure: 0x121c10: recovery action for unmapping failed page: Ignored
>
> Fixes: 70168fdc743b ("mm/memory-failure: check the mapcount of the precise page")
> Signed-off-by: Liu Shixin <liushixin2@huawei.com>
> ---
>  mm/memory-failure.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index f320ff02cc19..dba2936292cf 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1075,7 +1075,7 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
>  				unmap_success = false;
>  			}
>  		} else {
> -			unmap_success = try_to_unmap(p, ttu);
> +			unmap_success = try_to_unmap(hpage, ttu);
>  		}
>  	}
>  	if (!unmap_success)