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>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 199fa436c0ddfc49566a1221af9c3da788359b45..b94fe1b3da435f34f567e8a23358ec18ccd452ad 100644 (file)
--- 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);