Re: [PATCH 1/2] mm: page_isolation: check pfn validity before access

[Yasuaki Ishimatsu]

(2014/11/06 17:08), Weijie Yang wrote:
> In the undo path of start_isolate_page_range(), we need to check
> the pfn validity before access its page, or it will trigger an
> addressing exception if there is hole in the zone.
>
> Signed-off-by: Weijie Yang <weijie.yang@xxxxxxxxxxx>
> ---

Looks good to me.

Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>

Thanks,
Yasuaki Ishimatsu

>   mm/page_isolation.c |    7 +++++--
>   1 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> index d1473b2..3ddc8b3 100644
> --- a/mm/page_isolation.c
> +++ b/mm/page_isolation.c
> @@ -137,8 +137,11 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
>   undo:
>   	for (pfn = start_pfn;
>   	     pfn < undo_pfn;
> -	     pfn += pageblock_nr_pages)
> -		unset_migratetype_isolate(pfn_to_page(pfn), migratetype);
> +	     pfn += pageblock_nr_pages) {
> +		page = __first_valid_page(pfn, pageblock_nr_pages);
> +		if (page)
> +			unset_migratetype_isolate(page, migratetype);
> +	}
>
>   	return -EBUSY;
>   }


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