mm/vmscan.c: fix mapping use after free

We need lock_page_nosync() here because we have no reference to the
mapping when taking the page lock.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 199fa436c0dd..b94fe1b3da43 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -298,7 +298,7 @@ static int may_write_to_queue(struct backing_dev_info *bdi)
 static void handle_write_error(struct address_space *mapping,
                                 struct page *page, int error)
 {
-        lock_page(page);
+        lock_page_nosync(page);
         if (page_mapping(page) == mapping)
                 mapping_set_error(mapping, error);
         unlock_page(page);