From 2a1dc509747fdcfdf3a2df818a14908aed86c3d4 Mon Sep 17 00:00:00 2001
From: Johannes Weiner <hannes@saeurebad.de>
Date: Mon, 1 Dec 2008 03:00:35 +0100
Subject: [PATCH] vmscan: protect zone rotation stats by lru lock
The zone's rotation statistics must not be accessed without the
corresponding LRU lock held. Fix an unprotected write in
shrink_active_list().
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/vmscan.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 7ea1440b53db..62e7f62fb559 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1248,6 +1248,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
list_add(&page->lru, &l_inactive);
}
+ spin_lock_irq(&zone->lru_lock);
/*
* Count referenced pages from currently used mappings as
* rotated, even though they are moved to the inactive list.
@@ -1263,7 +1264,6 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
pgmoved = 0;
lru = LRU_BASE + file * LRU_FILE;
- spin_lock_irq(&zone->lru_lock);
while (!list_empty(&l_inactive)) {
page = lru_to_page(&l_inactive);
prefetchw_prev_lru_page(page, &l_inactive, flags);
--
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