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authorMichal Hocko <mhocko@suse.cz>2012-01-20 17:33:58 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-23 11:38:47 -0500
commit656a070629adfe23c12768e35ddf91feab469ff7 (patch)
tree42c001d079ec926186873b91d7d84bf66c54bcad /mm/page_alloc.c
parent687875fb7de4a95223af20ee024282fa9099f860 (diff)
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: Michal Hocko <mhocko@suse.cz> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 21c272d517bc..d2186ecb36f7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5413,15 +5413,22 @@ __count_immobile_pages(struct zone *zone, struct page *page, int count)
5413 5413
5414bool is_pageblock_removable_nolock(struct page *page) 5414bool is_pageblock_removable_nolock(struct page *page)
5415{ 5415{
5416 struct zone *zone = page_zone(page); 5416 struct zone *zone;
5417 unsigned long pfn = page_to_pfn(page); 5417 unsigned long pfn;
5418 5418
5419 /* 5419 /*
5420 * We have to be careful here because we are iterating over memory 5420 * We have to be careful here because we are iterating over memory
5421 * sections which are not zone aware so we might end up outside of 5421 * sections which are not zone aware so we might end up outside of
5422 * the zone but still within the section. 5422 * the zone but still within the section.
5423 * We have to take care about the node as well. If the node is offline
5424 * its NODE_DATA will be NULL - see page_zone.
5423 */ 5425 */
5424 if (!zone || zone->zone_start_pfn > pfn || 5426 if (!node_online(page_to_nid(page)))
5427 return false;
5428
5429 zone = page_zone(page);
5430 pfn = page_to_pfn(page);
5431 if (zone->zone_start_pfn > pfn ||
5425 zone->zone_start_pfn + zone->spanned_pages <= pfn) 5432 zone->zone_start_pfn + zone->spanned_pages <= pfn)
5426 return false; 5433 return false;
5427 5434