Mike Snitzer 4328daa2e7 dm: fix dm_rq_target_io leak on faults with .request_fn DM w/ blk-mq paths
Using request-based DM mpath configured with the following stacking
(.request_fn DM mpath ontop of scsi-mq paths):

echo Y > /sys/module/scsi_mod/parameters/use_blk_mq
echo N > /sys/module/dm_mod/parameters/use_blk_mq

'struct dm_rq_target_io' would leak if a request is requeued before a
blk-mq clone is allocated (or fails to allocate).  free_rq_tio()
wasn't being called.

kmemleak reported:

unreferenced object 0xffff8800b90b98c0 (size 112):
  comm "kworker/7:1H", pid 5692, jiffies 4295056109 (age 78.589s)
  hex dump (first 32 bytes):
    00 d0 5c 2c 03 88 ff ff 40 00 bf 01 00 c9 ff ff  ..\,....@.......
    e0 d9 b1 34 00 88 ff ff 00 00 00 00 00 00 00 00  ...4............
  backtrace:
    [<ffffffff81672b6e>] kmemleak_alloc+0x4e/0xb0
    [<ffffffff811dbb63>] kmem_cache_alloc+0xc3/0x1e0
    [<ffffffff8117eae5>] mempool_alloc_slab+0x15/0x20
    [<ffffffff8117ec1e>] mempool_alloc+0x6e/0x170
    [<ffffffffa00029ac>] dm_old_prep_fn+0x3c/0x180 [dm_mod]
    [<ffffffff812fbd78>] blk_peek_request+0x168/0x290
    [<ffffffffa0003e62>] dm_request_fn+0xb2/0x1b0 [dm_mod]
    [<ffffffff812f66e3>] __blk_run_queue+0x33/0x40
    [<ffffffff812f9585>] blk_delay_work+0x25/0x40
    [<ffffffff81096fff>] process_one_work+0x14f/0x3d0
    [<ffffffff81097715>] worker_thread+0x125/0x4b0
    [<ffffffff8109ce88>] kthread+0xd8/0xf0
    [<ffffffff8167cb8f>] ret_from_fork+0x3f/0x70
    [<ffffffffffffffff>] 0xffffffffffffffff

crash> struct -o dm_rq_target_io
struct dm_rq_target_io {
    ...
}
SIZE: 112

Fixes: e5863d9ad7 ("dm: allocate requests in target when stacking on blk-mq devices")
Cc: stable@vger.kernel.org # 4.0+
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-21 20:27:50 -05:00
..
2016-01-24 18:13:37 -08:00
2014-01-14 23:23:03 -05:00
2015-10-31 19:06:01 -04:00
2015-10-31 19:06:01 -04:00
2015-10-31 19:05:59 -04:00
2016-01-04 10:29:12 -05:00
2015-10-31 19:05:59 -04:00
2012-07-30 17:25:16 -07:00
2015-10-31 19:06:01 -04:00
2007-10-20 02:01:26 +01:00
2015-08-13 12:31:57 -06:00
2016-01-20 13:52:20 -08:00
2016-01-15 12:28:00 -08:00
2016-01-15 12:28:00 -08:00
2015-12-08 14:59:19 +01:00
2015-08-13 12:31:57 -06:00
2016-01-20 13:52:20 -08:00
2016-01-20 13:52:20 -08:00
2015-11-01 13:48:29 +11:00
2016-01-20 13:52:20 -08:00