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authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>2007-07-26 10:41:08 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-26 11:35:17 -0700
commit3dd9fe8c397df68086e6a1b2160573abbe944813 (patch)
tree86dda41ade146e2a403151c7ba2f7e32a930bc63 /mm
parentdc386d4d1e98bb39fb967ee156cd456c802fc692 (diff)
downloadlinux-3dd9fe8c397df68086e6a1b2160573abbe944813.tar.gz
memory unplug: isolate_lru_page fix
release_pages() in mm/swap.c changes page_count() to be 0 without removing
PageLRU flag...

This means isolate_lru_page() can see a page, PageLRU() &&
page_count(page)==0..  This is BUG.  (get_page() will be called against
count=0 page.)

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/migrate.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
index c8d87221f368..37c73b902008 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -49,9 +49,8 @@ int isolate_lru_page(struct page *page, struct list_head *pagelist)
 		struct zone *zone = page_zone(page);
 
 		spin_lock_irq(&zone->lru_lock);
-		if (PageLRU(page)) {
+		if (PageLRU(page) && get_page_unless_zero(page)) {
 			ret = 0;
-			get_page(page);
 			ClearPageLRU(page);
 			if (PageActive(page))
 				del_page_from_active_list(zone, page);