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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)
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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 c8d87221f36..37c73b90200 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);