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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+
hifive-unleashed-5.1
Bryn M. Reeves 2016-03-14 17:04:34 -04:00 committed by Mike Snitzer
parent c3667cc619
commit 98dbc9c6c6
1 changed files with 1 additions and 1 deletions
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2
drivers/md/dm.c
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@ -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