dm cache: Fix UAF in destroy()

Dm_cache also has the same UAF problem when dm_resume()
and dm_destroy() are concurrent.

Therefore, cancelling timer again in destroy().

Cc: stable@vger.kernel.org
Fixes: c6b4fcbad044e ("dm: add cache target")
Signed-off-by: Luo Meng <luomeng12@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 54a8d5c..624a633 100644 (file)
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -1887,6 +1887,7 @@ static void destroy(struct cache *cache)
        if (cache->prison)
                dm_bio_prison_destroy_v2(cache->prison);
 
+       cancel_delayed_work_sync(&cache->waker);
        if (cache->wq)
                destroy_workqueue(cache->wq);