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From: Peter Xu <peterx@redhat.com>
To: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
	Alistair Popple <apopple@nvidia.com>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Konstantin Khlebnikov <koct9i@gmail.com>,
	Bin Wang <wangbin224@huawei.com>,
	Naoya Horiguchi <naoya.horiguchi@nec.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1] mm, pagemap: expose hwpoison entry
Date: Wed, 13 Oct 2021 10:49:04 +0800	[thread overview]
Message-ID: <YWZJIKsn6Sry5P6k@t490s> (raw)
In-Reply-To: <20211004115001.1544259-1-naoya.horiguchi@linux.dev>

Hi, Naoya,

On Mon, Oct 04, 2021 at 08:50:01PM +0900, Naoya Horiguchi wrote:
> +static inline struct page *hwpoison_entry_to_page(swp_entry_t entry)
> +{
> +	struct page *p = pfn_to_page(swp_offset(entry));
> +
> +	WARN_ON(!PageHWPoison(p));
> +	return p;
> +}

This is more a pure question..

I'm wondering whether that WARN_ON() could trigger.

IOW, what if we poison an anonymous page and then unpoison it?  Will there be a
hwpoison swap entry leftover in the ptes that it used to map?  Will it crash
the program when the page is accessed?

I had a feeling that when handling the page fault in do_swap_page before we
SIGBUS the program, we should double-check the PageHWPoison on the pfn page,
but I could be missing something..

Thanks,

-- 
Peter Xu



  parent reply	other threads:[~2021-10-13  2:49 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-04 11:50 [PATCH v1] mm, pagemap: expose hwpoison entry Naoya Horiguchi
2021-10-04 11:55 ` David Hildenbrand
2021-10-04 14:32   ` Naoya Horiguchi
2021-10-26 23:27     ` Naoya Horiguchi
2021-10-27  2:09       ` Peter Xu
2021-10-27  6:45         ` Naoya Horiguchi
2021-10-27  7:02           ` Peter Xu
2021-10-27  7:15             ` David Hildenbrand
2021-10-04 20:17 ` kernel test robot
2021-10-04 20:17   ` kernel test robot
2021-10-05  2:53 ` kernel test robot
2021-10-05  2:53   ` kernel test robot
2021-10-13  2:49 ` Peter Xu [this message]
2021-10-14 13:36   ` Naoya Horiguchi
2021-10-14 23:32     ` Peter Xu

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