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From: David Hildenbrand <david@redhat.com>
To: Aili Yao <yaoaili@kingsoft.com>,
	akpm@linux-foundation.org, naoya.horiguchi@nec.com
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	yangfeng1@kingsoft.com, sunhao2@kingsoft.com,
	Oscar Salvador <osalvador@suse.de>,
	Mike Kravetz <mike.kravetz@oracle.com>
Subject: Re: [PATCH] mm/gup: check page posion status for coredump.
Date: Wed, 17 Mar 2021 10:12:02 +0100	[thread overview]
Message-ID: <20a0d078-f49d-54d6-9f04-f6b41dd51e5f@redhat.com> (raw)
In-Reply-To: <20210317163714.328a038d@alex-virtual-machine>

On 17.03.21 09:37, Aili Yao wrote:
> When we do coredump for user process signal, this may be an SIGBUS signal
> with BUS_MCEERR_AR or BUS_MCEERR_AO code, which means this signal is
> resulted from ECC memory fail like SRAR or SRAO, we expect the memory
> recovery work is finished correctly, then the get_dump_page() will not
> return the error page as its process pte is set invalid by
> memory_failure().
> 
> But memory_failure() may fail, and the process's related pte may not be
> correctly set invalid, for current code, we will return the poison page
> and get it dumped and lead to system panic as its in kernel code.
> 
> So check the poison status in get_dump_page(), and if TRUE, return NULL.
> 
> Signed-off-by: Aili Yao <yaoaili@kingsoft.com>
> ---
>   mm/gup.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
> 
> diff --git a/mm/gup.c b/mm/gup.c
> index e4c224c..499a496 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -1536,6 +1536,14 @@ struct page *get_dump_page(unsigned long addr)
>   				      FOLL_FORCE | FOLL_DUMP | FOLL_GET);
>   	if (locked)
>   		mmap_read_unlock(mm);
> +
> +	if (IS_ENABLED(CONFIG_MEMORY_FAILURE) && ret == 1) {
> +		if (unlikely(PageHuge(page) && PageHWPoison(compound_head(page))))
> +			ret = 0;
> +		else if (unlikely(PageHWPoison(page)))
> +			ret = 0;
> +	}

I wonder if a simple

if (PageHWPoison(compound_head(page)))
	ret = 0;

won't suffice. But I guess the "issue" is compound pages that are not 
huge pages or transparent huge pages.

If not, we certainly want a wrapper for that magic, otherwise we have to 
replicate the same logic all over the place.

> +
>   	return (ret == 1) ? page : NULL;
>   }
>   #endif /* CONFIG_ELF_CORE */
> 


-- 
Thanks,

David / dhildenb



  reply	other threads:[~2021-03-17  9:12 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-17  8:37 [PATCH] mm/gup: check page posion status for coredump Aili Yao
2021-03-17  9:12 ` David Hildenbrand [this message]
2021-03-18  3:15   ` Aili Yao
2021-03-18  3:18   ` [PATCH v2] " Aili Yao
2021-03-18  4:46   ` [PATCH] " Matthew Wilcox
2021-03-18  5:34     ` Aili Yao
2021-03-19  2:44       ` [PATCH v3] " Aili Yao
2021-03-20  0:35         ` Matthew Wilcox
2021-03-22  3:40           ` Aili Yao
2021-03-22 11:33           ` [PATCH v5] mm/gup: check page hwposion " Aili Yao
2021-03-26 14:09             ` David Hildenbrand
2021-03-26 14:22               ` David Hildenbrand
2021-03-31  1:52                 ` HORIGUCHI NAOYA(堀口 直也)
2021-03-31  2:43                   ` Aili Yao
2021-03-31  4:32                     ` HORIGUCHI NAOYA(堀口 直也)
2021-03-31  6:44                       ` David Hildenbrand
2021-03-31  7:07                         ` Aili Yao
2021-04-01  2:31                         ` Aili Yao
2021-04-06  2:23                         ` [PATCH v6] mm/gup: check page hwpoison status for memory recovery failures Aili Yao
2021-04-06  2:41                           ` [PATCH v7] " Aili Yao
2021-04-07  1:54                             ` HORIGUCHI NAOYA(堀口 直也)
2021-04-07  7:48                               ` Aili Yao
2021-05-10  3:13                             ` Aili Yao
2021-03-31  6:07                   ` [PATCH v5] mm/gup: check page hwposion status for coredump Matthew Wilcox
2021-03-31  6:53                     ` HORIGUCHI NAOYA(堀口 直也)
2021-03-31  7:05                       ` David Hildenbrand
2021-03-18  8:14     ` [PATCH] mm/gup: check page posion " David Hildenbrand

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