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 <bmr@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Fixes: e262f34741 ("dm stats: add support for request-based DM devices")
Cc: stable@vger.kernel.org # 4.2+
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 70d5b82a3..be49057 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1254,9 +1254,9 @@
{
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