Commit 4c6dd53d authored May 27, 2015 by Mike Snitzer

dm mpath: fix leak of dm_mpath_io structure in blk-mq .queue_rq error path



Otherwise kmemleak reported:

unreferenced object 0xffff88009b14e2b0 (size 16):
  comm "fio", pid 4274, jiffies 4294978034 (age 1253.210s)
  hex dump (first 16 bytes):
    40 12 f3 99 01 88 ff ff 00 10 00 00 00 00 00 00  @...............
  backtrace:
    [<ffffffff81600029>] kmemleak_alloc+0x49/0xb0
    [<ffffffff811679a8>] kmem_cache_alloc+0xf8/0x160
    [<ffffffff8111c950>] mempool_alloc_slab+0x10/0x20
    [<ffffffff8111cb37>] mempool_alloc+0x57/0x150
    [<ffffffffa04d2b61>] __multipath_map.isra.17+0xe1/0x220 [dm_multipath]
    [<ffffffffa04d2cb5>] multipath_clone_and_map+0x15/0x20 [dm_multipath]
    [<ffffffffa02889b5>] map_request.isra.39+0xd5/0x220 [dm_mod]
    [<ffffffffa028b0e4>] dm_mq_queue_rq+0x134/0x240 [dm_mod]
    [<ffffffff812cccb5>] __blk_mq_run_hw_queue+0x1d5/0x380
    [<ffffffff812ccaa5>] blk_mq_run_hw_queue+0xc5/0x100
    [<ffffffff812ce350>] blk_sq_make_request+0x240/0x300
    [<ffffffff812c0f30>] generic_make_request+0xc0/0x110
    [<ffffffff812c0ff2>] submit_bio+0x72/0x150
    [<ffffffff811c07cb>] do_blockdev_direct_IO+0x1f3b/0x2da0
    [<ffffffff811c166e>] __blockdev_direct_IO+0x3e/0x40
    [<ffffffff8120aa1a>] ext4_direct_IO+0x1aa/0x390

Fixes: e5863d9a ("dm: allocate requests in target when stacking on blk-mq devices")
Reported-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 4.0+

parent 3a140755

drivers/md/dm-mpath.c

+3 −1

Original line number	Original line	Diff line number	Diff line
	@@ -429,9 +429,11 @@ static int __multipath_map(struct dm_target ti, struct request clone,
	/* blk-mq request-based interface */		/* blk-mq request-based interface */
	*__clone = blk_get_request(bdev_get_queue(bdev),		*__clone = blk_get_request(bdev_get_queue(bdev),
	rq_data_dir(rq), GFP_ATOMIC);		rq_data_dir(rq), GFP_ATOMIC);
	if (IS_ERR(*__clone))		if (IS_ERR(*__clone)) {
	/* ENOMEM, requeue */		/* ENOMEM, requeue */
			clear_mapinfo(m, map_context);
	return r;		return r;
			}
	(__clone)->bio = (__clone)->biotail = NULL;		(__clone)->bio = (__clone)->biotail = NULL;
	(*__clone)->rq_disk = bdev->bd_disk;		(*__clone)->rq_disk = bdev->bd_disk;
	(*__clone)->cmd_flags \|= REQ_FAILFAST_TRANSPORT;		(*__clone)->cmd_flags \|= REQ_FAILFAST_TRANSPORT;

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