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 <[email protected]>
Signed-off-by: Mike Snitzer <[email protected]>
Fixes: e262f34741 ("dm stats: add support for request-based DM devices")
Cc: [email protected] # 4.2+
This commit is contained in:
Bryn M. Reeves 2016-03-14 17:04:34 -04:00 • committed by Mike Snitzer
commit 98dbc9c6c6

View file

@ -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