Subject: Re: [PATCH] mm, sparse: fix typo in online_mem_sections
To: Michal Hocko <mhocko@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
        Michal Hocko <mhocko@suse.com>
References: <20170904112210.3401-1-mhocko@kernel.org>
From: Vlastimil Babka <vbabka@suse.cz>
Message-ID: <a5386f27-cbdf-dbab-ee9f-cc2a1ee48572@suse.cz>
Date: Wed, 6 Sep 2017 10:18:18 +0200
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On 09/04/2017 01:22 PM, Michal Hocko wrote:
> From: Michal Hocko <mhocko@suse.com>
> 
> online_mem_sections accidentally marks online only the first section in
> the given range. This is a typo which hasn't been noticed because I
> haven't tested large 2GB blocks previously. All users of
> pfn_to_online_page would get confused on the the rest of the pfn range
> in the block.
> 
> All we need to fix this is to use iterator (pfn) rather than start_pfn.
> 
> Fixes: 2d070eab2e82 ("mm: consider zone which is not fully populated to have holes")
> Cc: stable
> Signed-off-by: Michal Hocko <mhocko@suse.com>

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

> ---
>  mm/sparse.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/sparse.c b/mm/sparse.c
> index a9783acf2bb9..83b3bf6461af 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -626,7 +626,7 @@ void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
>  	unsigned long pfn;
>  
>  	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
> -		unsigned long section_nr = pfn_to_section_nr(start_pfn);
> +		unsigned long section_nr = pfn_to_section_nr(pfn);
>  		struct mem_section *ms;
>  
>  		/* onlining code should never touch invalid ranges */
>