From 98dbc9c6c61698792e3a66f32f3bf066201d42d7 Mon Sep 17 00:00:00 2001 From: "Bryn M. Reeves" Date: Mon, 14 Mar 2016 17:04:34 -0400 Subject: [PATCH] dm: fix rq_end_stats() NULL pointer in dm_requeue_original_request() An "old" (.request_fn) DM 'struct request' stores a pointer to the associated 'struct dm_rq_target_io' in rq->special. dm_requeue_original_request(), previously named dm_requeue_unmapped_original_request(), called dm_unprep_request() to reset rq->special to NULL. But rq_end_stats() would go on to hit a NULL pointer deference because its call to tio_from_request() returned NULL. Fix this by calling rq_end_stats() _before_ dm_unprep_request() Signed-off-by: Bryn M. Reeves Signed-off-by: Mike Snitzer Fixes: e262f34741 ("dm stats: add support for request-based DM devices") Cc: stable@vger.kernel.org # 4.2+ --- drivers/md/dm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 70d5b82a353a..be4905769a45 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1254,9 +1254,9 @@ static void dm_requeue_original_request(struct mapped_device *md, { int rw = rq_data_dir(rq); + rq_end_stats(md, rq); dm_unprep_request(rq); - rq_end_stats(md, rq); if (!rq->q->mq_ops) dm_old_requeue_request(rq); else -- 2.20.1