linux-kernel - drivers/md/dm-mpath.c:524 multipath_clone_and_map() error: double unlocked 'm->lock' (orig line 516)

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Date:   Sat, 8 Aug 2020 20:10:00 +0800
From:   kernel test robot <lkp@...el.com>
To:     Mike Snitzer <snitzer@...hat.com>
Cc:     kbuild-all@...ts.01.org, linux-kernel@...r.kernel.org
Subject: drivers/md/dm-mpath.c:524 multipath_clone_and_map() error: double
 unlocked 'm->lock' (orig line 516)

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   449dc8c97089a6e09fb2dac4d92b1b7ac0eb7c1e
commit: 374117ad4736c5a4f8012cfe59fc07d9d58191d5 dm mpath: use double checked locking in fast path
date:   4 weeks ago
config: arm-randconfig-m031-20200808 (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@...el.com>

New smatch warnings:
drivers/md/dm-mpath.c:524 multipath_clone_and_map() error: double unlocked 'm->lock' (orig line 516)

Old smatch warnings:
drivers/md/dm-mpath.c:446 choose_pgpath() error: double unlocked 'm->lock' (orig line 416)
drivers/md/dm-mpath.c:457 choose_pgpath() error: double unlocked 'm->lock' (orig line 403)
drivers/md/dm-mpath.c:525 multipath_clone_and_map() error: double unlocked 'm->lock' (orig line 516)
drivers/md/dm-mpath.c:526 multipath_clone_and_map() error: double unlocked 'm->lock' (orig line 524)
drivers/md/dm-mpath.c:626 __map_bio() error: double unlocked 'm->lock' (orig line 615)
drivers/md/dm-mpath.c:627 __map_bio() error: double unlocked 'm->lock' (orig line 615)
drivers/md/dm-mpath.c:628 __map_bio() error: double unlocked 'm->lock' (orig line 626)
drivers/md/dm-mpath.c:629 __map_bio() error: double unlocked 'm->lock' (orig line 628)
drivers/md/dm-mpath.c:1607 pg_init_done() error: double unlocked 'm->lock' (orig line 1560)
drivers/md/dm-mpath.c:1707 multipath_end_io_bio() error: double unlocked 'm->lock' (orig line 1704)
drivers/md/dm-mpath.c:1988 multipath_prepare_ioctl() error: double unlocked 'm->lock' (orig line 1984)
drivers/md/dm-mpath.c:2012 multipath_prepare_ioctl() error: double unlocked 'm->lock' (orig line 2001)

vim +524 drivers/md/dm-mpath.c

   498	
   499	/*
   500	 * Map cloned requests (request-based multipath)
   501	 */
   502	static int multipath_clone_and_map(struct dm_target *ti, struct request *rq,
   503					   union map_info *map_context,
   504					   struct request **__clone)
   505	{
   506		struct multipath *m = ti->private;
   507		size_t nr_bytes = blk_rq_bytes(rq);
   508		struct pgpath *pgpath;
   509		struct block_device *bdev;
   510		struct dm_mpath_io *mpio = get_mpio(map_context);
   511		struct request_queue *q;
   512		struct request *clone;
   513	
   514		/* Do we need to select a new pgpath? */
   515		pgpath = READ_ONCE(m->current_pgpath);
 > 516		if (!pgpath || !mpath_double_check_test_bit(MPATHF_QUEUE_IO, m))
   517			pgpath = choose_pgpath(m, nr_bytes);
   518	
   519		if (!pgpath) {
   520			if (must_push_back_rq(m))
   521				return DM_MAPIO_DELAY_REQUEUE;
   522			dm_report_EIO(m);	/* Failed */
   523			return DM_MAPIO_KILL;
 > 524		} else if (mpath_double_check_test_bit(MPATHF_QUEUE_IO, m) ||
   525			   mpath_double_check_test_bit(MPATHF_PG_INIT_REQUIRED, m)) {
   526			pg_init_all_paths(m);
   527			return DM_MAPIO_DELAY_REQUEUE;
   528		}
   529	
   530		mpio->pgpath = pgpath;
   531		mpio->nr_bytes = nr_bytes;
   532	
   533		bdev = pgpath->path.dev->bdev;
   534		q = bdev_get_queue(bdev);
   535		clone = blk_get_request(q, rq->cmd_flags | REQ_NOMERGE,
   536				BLK_MQ_REQ_NOWAIT);
   537		if (IS_ERR(clone)) {
   538			/* EBUSY, ENODEV or EWOULDBLOCK: requeue */
   539			if (blk_queue_dying(q)) {
   540				atomic_inc(&m->pg_init_in_progress);
   541				activate_or_offline_path(pgpath);
   542				return DM_MAPIO_DELAY_REQUEUE;
   543			}
   544	
   545			/*
   546			 * blk-mq's SCHED_RESTART can cover this requeue, so we
   547			 * needn't deal with it by DELAY_REQUEUE. More importantly,
   548			 * we have to return DM_MAPIO_REQUEUE so that blk-mq can
   549			 * get the queue busy feedback (via BLK_STS_RESOURCE),
   550			 * otherwise I/O merging can suffer.
   551			 */
   552			return DM_MAPIO_REQUEUE;
   553		}
   554		clone->bio = clone->biotail = NULL;
   555		clone->rq_disk = bdev->bd_disk;
   556		clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
   557		*__clone = clone;
   558	
   559		if (pgpath->pg->ps.type->start_io)
   560			pgpath->pg->ps.type->start_io(&pgpath->pg->ps,
   561						      &pgpath->path,
   562						      nr_bytes);
   563		return DM_MAPIO_REMAPPED;
   564	}
   565	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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