| From | Kamal Mostafa <> | Subject | [PATCH 4.2.y-ckt 115/218] dm: fix rq_end_stats() NULL pointer in dm_requeue_original_request() | Date | Thu, 31 Mar 2016 13:15:28 -0700 |
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4.2.8-ckt7 -stable review patch. If anyone has any objections, please let me know.
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From: "Bryn M. Reeves" <bmr@redhat.com>
commit 98dbc9c6c61698792e3a66f32f3bf066201d42d7 upstream.
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") Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- 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 3f82998..e066983 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1184,9 +1184,9 @@ 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) old_requeue_request(rq); else { -- 2.7.4
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