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Commit 656a0706 authored by Michal Hocko's avatar Michal Hocko Committed by Linus Torvalds
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mm: __count_immobile_pages(): make sure the node is online 



page_zone() requires an online node otherwise we are accessing NULL
NODE_DATA.  This is not an issue at the moment because node_zones are
located at the structure beginning but this might change in the future
so better be careful about that.

Signed-off-by: default avatarMichal Hocko <mhocko@suse.cz>
Signed-off-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: default avatarMel Gorman <mgorman@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 687875fb

mm/page_alloc.c

+10 −3
Original line number Diff line number Diff line
@@ -5413,15 +5413,22 @@ __count_immobile_pages(struct zone *zone, struct page *page, int count) 


bool is_pageblock_removable_nolock(struct page *page)

{

	struct zone *zone = page_zone(page);

	unsigned long pfn = page_to_pfn(page);

	struct zone *zone;

	unsigned long pfn;



	/*

	 * We have to be careful here because we are iterating over memory

	 * sections which are not zone aware so we might end up outside of

	 * the zone but still within the section.

	 * We have to take care about the node as well. If the node is offline

	 * its NODE_DATA will be NULL - see page_zone.

	 */

	if (!zone || zone->zone_start_pfn > pfn ||

	if (!node_online(page_to_nid(page)))

		return false;



	zone = page_zone(page);

	pfn = page_to_pfn(page);

	if (zone->zone_start_pfn > pfn ||

			zone->zone_start_pfn + zone->spanned_pages <= pfn)

		return false;