[PATCH 1/2] Check PageUnevictable in lru_deactivate_fn

[Minchan Kim <minchan.kim@gmail.com>]

The lru_deactivate_fn should not move page which in on unevictable lru
into inactive list. Otherwise, we can meet BUG when we use isolate_lru_pages
as __isolate_lru_page could return -EINVAL.
It's really BUG and let's fix it.

Reported-by: Ying Han <yinghan@google.com>
Tested-by: Ying Han <yinghan@google.com>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
---
 mm/swap.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index a83ec5a..2e9656d 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -429,6 +429,9 @@ static void lru_deactivate_fn(struct page *page, void *arg)
 	if (!PageLRU(page))
 		return;
 
+	if (PageUnevictable(page))
+		return;
+
 	/* Some processes are using the page */
 	if (page_mapped(page))
 		return;
-- 
1.7.1

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