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From: Vlastimil Babka <vbabka@suse.cz>
To: "Matthew Wilcox (Oracle)" <willy@infradead.org>, linux-mm@kvack.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
	John Hubbard <jhubbard@nvidia.com>,
	"Kirill A. Shutemov" <kirill@shutemov.name>,
	William Kucharski <william.kucharski@oracle.com>,
	Mike Rapoport <rppt@linux.ibm.com>
Subject: Re: [PATCH v2 1/6] mm: Handle page->mapping better in dump_page
Date: Tue, 14 Jul 2020 13:06:20 +0200
Message-ID: <ff517ba0-a2e2-3438-d148-cb01b89f4eda@suse.cz> (raw)
In-Reply-To: <20200709202117.7216-2-willy@infradead.org>

On 7/9/20 10:21 PM, Matthew Wilcox (Oracle) wrote:
> If we can't call page_mapping() to get the page mapping, handle the
> anon/ksm/movable bits correctly.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

John's updated comment looks fine too.

> ---
>  mm/debug.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/debug.c b/mm/debug.c
> index 4f376514744d..e5de63406b59 100644
> --- a/mm/debug.c
> +++ b/mm/debug.c
> @@ -70,7 +70,12 @@ void __dump_page(struct page *page, const char *reason)
>  
>  	if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) {
>  		/* Corrupt page, cannot call page_mapping */
> -		mapping = page->mapping;
> +		unsigned long tmp = (unsigned long)page->mapping;
> +
> +		if (tmp & PAGE_MAPPING_ANON)
> +			mapping = NULL;
> +		else
> +			mapping = (void *)(tmp & ~PAGE_MAPPING_FLAGS);
>  		head = page;
>  		compound = false;
>  	} else {
> 



  parent reply index

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-09 20:21 [PATCH v2 0/6] Improvements for dump_page() Matthew Wilcox (Oracle)
2020-07-09 20:21 ` [PATCH v2 1/6] mm: Handle page->mapping better in dump_page Matthew Wilcox (Oracle)
2020-07-11  1:30   ` John Hubbard
2020-07-11  1:32     ` John Hubbard
2020-07-14 11:06   ` Vlastimil Babka [this message]
2020-07-09 20:21 ` [PATCH v2 2/6] mm: Dump compound page information on a second line Matthew Wilcox (Oracle)
2020-07-11  1:35   ` John Hubbard
2020-07-14 12:03   ` Vlastimil Babka
2020-08-04 15:37   ` Qian Cai
2020-08-04 16:14     ` Matthew Wilcox
2020-08-04 18:39       ` [PATCH] mm, dump_page: do not crash with bad compound_page() John Hubbard
2020-08-04 18:48         ` Matthew Wilcox
2020-08-04 19:17           ` John Hubbard
2020-08-04 19:42             ` Matthew Wilcox
2020-07-09 20:21 ` [PATCH v2 3/6] mm: Print head flags in dump_page Matthew Wilcox (Oracle)
2020-07-11  1:40   ` John Hubbard
2020-07-14 12:06   ` Vlastimil Babka
2020-07-09 20:21 ` [PATCH v2 4/6] mm: Switch dump_page to get_kernel_nofault Matthew Wilcox (Oracle)
2020-07-14 12:11   ` Vlastimil Babka
2020-07-09 20:21 ` [PATCH v2 5/6] mm: Print the inode number in dump_page Matthew Wilcox (Oracle)
2020-07-11  2:04   ` John Hubbard
2020-07-14 12:18   ` Vlastimil Babka
2020-07-09 20:21 ` [PATCH v2 6/6] mm: Print hashed address of struct page Matthew Wilcox (Oracle)
2020-07-11  1:48   ` John Hubbard
2020-07-09 20:54 ` [PATCH v2 0/6] Improvements for dump_page() Mike Rapoport
2020-07-09 20:54 ` William Kucharski

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