This is a note to let you know that I've just added the patch titled dm: fix dm_rq_target_io leak on faults with .request_fn DM w/ blk-mq paths to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: dm-fix-dm_rq_target_io-leak-on-faults-with-.request_fn-dm-w-blk-mq-paths.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 4328daa2e79ed904a42ce00a9f38b9c36b44b21a Mon Sep 17 00:00:00 2001 From: Mike Snitzer <snitzer@xxxxxxxxxx> Date: Sun, 21 Feb 2016 19:09:22 -0500 Subject: dm: fix dm_rq_target_io leak on faults with .request_fn DM w/ blk-mq paths From: Mike Snitzer <snitzer@xxxxxxxxxx> commit 4328daa2e79ed904a42ce00a9f38b9c36b44b21a upstream. 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") Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/md/dm.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1191,6 +1191,8 @@ static void dm_unprep_request(struct req if (clone) free_rq_clone(clone); + else if (!tio->md->queue->mq_ops) + free_rq_tio(tio); } /* Patches currently in stable-queue which might be from snitzer@xxxxxxxxxx are queue-4.4/dm-snapshot-fix-hung-bios-when-copy-error-occurs.patch queue-4.4/dm-space-map-metadata-remove-unused-variable-in-brb_pop.patch queue-4.4/dm-fix-dm_rq_target_io-leak-on-faults-with-.request_fn-dm-w-blk-mq-paths.patch queue-4.4/dm-thin-fix-race-condition-when-destroying-thin-pool-workqueue.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html