linux/drivers/md
Guoqing Jiang 868b8e43a0 md: don't flush workqueue unconditionally in md_open
[ Upstream commit f6766ff6af ]

We need to check mddev->del_work before flush workqueu since the purpose
of flush is to ensure the previous md is disappeared. Otherwise the similar
deadlock appeared if LOCKDEP is enabled, it is due to md_open holds the
bdev->bd_mutex before flush workqueue.

kernel: [  154.522645] ======================================================
kernel: [  154.522647] WARNING: possible circular locking dependency detected
kernel: [  154.522650] 5.6.0-rc7-lp151.27-default #25 Tainted: G           O
kernel: [  154.522651] ------------------------------------------------------
kernel: [  154.522653] mdadm/2482 is trying to acquire lock:
kernel: [  154.522655] ffff888078529128 ((wq_completion)md_misc){+.+.}, at: flush_workqueue+0x84/0x4b0
kernel: [  154.522673]
kernel: [  154.522673] but task is already holding lock:
kernel: [  154.522675] ffff88804efa9338 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x79/0x590
kernel: [  154.522691]
kernel: [  154.522691] which lock already depends on the new lock.
kernel: [  154.522691]
kernel: [  154.522694]
kernel: [  154.522694] the existing dependency chain (in reverse order) is:
kernel: [  154.522696]
kernel: [  154.522696] -> #4 (&bdev->bd_mutex){+.+.}:
kernel: [  154.522704]        __mutex_lock+0x87/0x950
kernel: [  154.522706]        __blkdev_get+0x79/0x590
kernel: [  154.522708]        blkdev_get+0x65/0x140
kernel: [  154.522709]        blkdev_get_by_dev+0x2f/0x40
kernel: [  154.522716]        lock_rdev+0x3d/0x90 [md_mod]
kernel: [  154.522719]        md_import_device+0xd6/0x1b0 [md_mod]
kernel: [  154.522723]        new_dev_store+0x15e/0x210 [md_mod]
kernel: [  154.522728]        md_attr_store+0x7a/0xc0 [md_mod]
kernel: [  154.522732]        kernfs_fop_write+0x117/0x1b0
kernel: [  154.522735]        vfs_write+0xad/0x1a0
kernel: [  154.522737]        ksys_write+0xa4/0xe0
kernel: [  154.522745]        do_syscall_64+0x64/0x2b0
kernel: [  154.522748]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
kernel: [  154.522749]
kernel: [  154.522749] -> #3 (&mddev->reconfig_mutex){+.+.}:
kernel: [  154.522752]        __mutex_lock+0x87/0x950
kernel: [  154.522756]        new_dev_store+0xc9/0x210 [md_mod]
kernel: [  154.522759]        md_attr_store+0x7a/0xc0 [md_mod]
kernel: [  154.522761]        kernfs_fop_write+0x117/0x1b0
kernel: [  154.522763]        vfs_write+0xad/0x1a0
kernel: [  154.522765]        ksys_write+0xa4/0xe0
kernel: [  154.522767]        do_syscall_64+0x64/0x2b0
kernel: [  154.522769]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
kernel: [  154.522770]
kernel: [  154.522770] -> #2 (kn->count#253){++++}:
kernel: [  154.522775]        __kernfs_remove+0x253/0x2c0
kernel: [  154.522778]        kernfs_remove+0x1f/0x30
kernel: [  154.522780]        kobject_del+0x28/0x60
kernel: [  154.522783]        mddev_delayed_delete+0x24/0x30 [md_mod]
kernel: [  154.522786]        process_one_work+0x2a7/0x5f0
kernel: [  154.522788]        worker_thread+0x2d/0x3d0
kernel: [  154.522793]        kthread+0x117/0x130
kernel: [  154.522795]        ret_from_fork+0x3a/0x50
kernel: [  154.522796]
kernel: [  154.522796] -> #1 ((work_completion)(&mddev->del_work)){+.+.}:
kernel: [  154.522800]        process_one_work+0x27e/0x5f0
kernel: [  154.522802]        worker_thread+0x2d/0x3d0
kernel: [  154.522804]        kthread+0x117/0x130
kernel: [  154.522806]        ret_from_fork+0x3a/0x50
kernel: [  154.522807]
kernel: [  154.522807] -> #0 ((wq_completion)md_misc){+.+.}:
kernel: [  154.522813]        __lock_acquire+0x1392/0x1690
kernel: [  154.522816]        lock_acquire+0xb4/0x1a0
kernel: [  154.522818]        flush_workqueue+0xab/0x4b0
kernel: [  154.522821]        md_open+0xb6/0xc0 [md_mod]
kernel: [  154.522823]        __blkdev_get+0xea/0x590
kernel: [  154.522825]        blkdev_get+0x65/0x140
kernel: [  154.522828]        do_dentry_open+0x1d1/0x380
kernel: [  154.522831]        path_openat+0x567/0xcc0
kernel: [  154.522834]        do_filp_open+0x9b/0x110
kernel: [  154.522836]        do_sys_openat2+0x201/0x2a0
kernel: [  154.522838]        do_sys_open+0x57/0x80
kernel: [  154.522840]        do_syscall_64+0x64/0x2b0
kernel: [  154.522842]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
kernel: [  154.522844]
kernel: [  154.522844] other info that might help us debug this:
kernel: [  154.522844]
kernel: [  154.522846] Chain exists of:
kernel: [  154.522846]   (wq_completion)md_misc --> &mddev->reconfig_mutex --> &bdev->bd_mutex
kernel: [  154.522846]
kernel: [  154.522850]  Possible unsafe locking scenario:
kernel: [  154.522850]
kernel: [  154.522852]        CPU0                    CPU1
kernel: [  154.522853]        ----                    ----
kernel: [  154.522854]   lock(&bdev->bd_mutex);
kernel: [  154.522856]                                lock(&mddev->reconfig_mutex);
kernel: [  154.522858]                                lock(&bdev->bd_mutex);
kernel: [  154.522860]   lock((wq_completion)md_misc);
kernel: [  154.522861]
kernel: [  154.522861]  *** DEADLOCK ***
kernel: [  154.522861]
kernel: [  154.522864] 1 lock held by mdadm/2482:
kernel: [  154.522865]  #0: ffff88804efa9338 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x79/0x590
kernel: [  154.522868]
kernel: [  154.522868] stack backtrace:
kernel: [  154.522873] CPU: 1 PID: 2482 Comm: mdadm Tainted: G           O      5.6.0-rc7-lp151.27-default #25
kernel: [  154.522875] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
kernel: [  154.522878] Call Trace:
kernel: [  154.522881]  dump_stack+0x8f/0xcb
kernel: [  154.522884]  check_noncircular+0x194/0x1b0
kernel: [  154.522888]  ? __lock_acquire+0x1392/0x1690
kernel: [  154.522890]  __lock_acquire+0x1392/0x1690
kernel: [  154.522893]  lock_acquire+0xb4/0x1a0
kernel: [  154.522895]  ? flush_workqueue+0x84/0x4b0
kernel: [  154.522898]  flush_workqueue+0xab/0x4b0
kernel: [  154.522900]  ? flush_workqueue+0x84/0x4b0
kernel: [  154.522905]  ? md_open+0xb6/0xc0 [md_mod]
kernel: [  154.522908]  md_open+0xb6/0xc0 [md_mod]
kernel: [  154.522910]  __blkdev_get+0xea/0x590
kernel: [  154.522912]  ? bd_acquire+0xc0/0xc0
kernel: [  154.522914]  blkdev_get+0x65/0x140
kernel: [  154.522916]  ? bd_acquire+0xc0/0xc0
kernel: [  154.522918]  do_dentry_open+0x1d1/0x380
kernel: [  154.522921]  path_openat+0x567/0xcc0
kernel: [  154.522923]  ? __lock_acquire+0x380/0x1690
kernel: [  154.522926]  do_filp_open+0x9b/0x110
kernel: [  154.522929]  ? __alloc_fd+0xe5/0x1f0
kernel: [  154.522935]  ? kmem_cache_alloc+0x28c/0x630
kernel: [  154.522939]  ? do_sys_openat2+0x201/0x2a0
kernel: [  154.522941]  do_sys_openat2+0x201/0x2a0
kernel: [  154.522944]  do_sys_open+0x57/0x80
kernel: [  154.522946]  do_syscall_64+0x64/0x2b0
kernel: [  154.522948]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
kernel: [  154.522951] RIP: 0033:0x7f98d279d9ae

And md_alloc also flushed the same workqueue, but the thing is different
here. Because all the paths call md_alloc don't hold bdev->bd_mutex, and
the flush is necessary to avoid race condition, so leave it as it is.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-22 09:05:17 +02:00
..
bcache bcache: explicity type cast in bset_bkey_last() 2020-02-24 08:34:53 +01:00
persistent-data dm space map common: fix to ensure new block isn't already in use 2020-02-11 04:34:03 -08:00
dm-bio-prison-v1.c dm: adjust structure members to improve alignment 2018-06-08 11:53:14 -04:00
dm-bio-prison-v1.h block: switch bios to blk_status_t 2017-06-09 09:27:32 -06:00
dm-bio-prison-v2.c dm: adjust structure members to improve alignment 2018-06-08 11:53:14 -04:00
dm-bio-prison-v2.h dm bio prison v2: new interface for the bio prison 2017-03-07 11:30:16 -05:00
dm-bio-record.h dm bio record: save/restore bi_end_io and bi_integrity 2020-03-25 08:06:07 +01:00
dm-bufio.c Revert "dm bufio: fix deadlock with loop device" 2019-08-29 08:28:49 +02:00
dm-builtin.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dm-cache-background-tracker.c dm cache background tracker: fix sparse warning 2018-04-30 15:40:40 -04:00
dm-cache-background-tracker.h dm cache: significant rework to leverage dm-bio-prison-v2 2017-03-07 13:28:31 -05:00
dm-cache-block-types.h linux: drop __bitwise__ everywhere 2016-12-16 00:13:41 +02:00
dm-cache-metadata.c dm cache metadata: Fix loading discard bitset 2019-05-25 18:23:38 +02:00
dm-cache-metadata.h dm cache: significant rework to leverage dm-bio-prison-v2 2017-03-07 13:28:31 -05:00
dm-cache-policy-internal.h dm cache: significant rework to leverage dm-bio-prison-v2 2017-03-07 13:28:31 -05:00
dm-cache-policy-smq.c treewide: Use array_size() in vzalloc() 2018-06-12 16:19:22 -07:00
dm-cache-policy.c
dm-cache-policy.h dm cache: significant rework to leverage dm-bio-prison-v2 2017-03-07 13:28:31 -05:00
dm-cache-target.c dm cache: fix a crash due to incorrect work item cancelling 2020-03-11 14:15:05 +01:00
dm-core.h dm: disable DISCARD if the underlying storage no longer supports it 2019-08-25 10:48:01 +02:00
dm-crypt.c dm crypt: fix benbi IV constructor crash if used in authenticated mode 2020-02-11 04:34:04 -08:00
dm-delay.c dm delay: fix a crash when invalid device is specified 2019-05-25 18:23:39 +02:00
dm-era-target.c dm: allow targets to return output from messages they are sent 2018-04-03 15:04:10 -04:00
dm-exception-store.c - Revert a dm-multipath change that caused a regression for unprivledged 2015-11-04 21:19:53 -08:00
dm-exception-store.h dm snapshot: fix hung bios when copy error occurs 2016-01-08 20:03:05 -05:00
dm-flakey.c dm flakey: Properly corrupt multi-page bios. 2019-12-05 09:20:36 +01:00
dm-integrity.c dm integrity: use dm_bio_record and dm_bio_restore 2020-03-25 08:06:07 +01:00
dm-io.c dm: Use kzalloc for all structs with embedded biosets/mempools 2018-06-05 08:47:43 -06:00
dm-ioctl.c dm ioctl: harden copy_params()'s copy_from_user() from malicious users 2018-11-13 11:08:49 -08:00
dm-kcopyd.c dm kcopyd: always complete failed jobs 2019-08-29 08:28:55 +02:00
dm-linear.c dm: Check for device sector overflow if CONFIG_LBDAF is not set 2019-01-26 09:32:42 +01:00
dm-log-userspace-base.c dm: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
dm-log-userspace-transfer.c dm log userspace transfer: match wait_for_completion_timeout return type 2015-04-15 12:10:20 -04:00
dm-log-userspace-transfer.h
dm-log-writes.c dm log writes: make sure super sector log updates are written in order 2019-07-03 13:14:45 +02:00
dm-log.c block,fs: use REQ_* flags directly 2016-11-01 09:43:26 -06:00
dm-mpath.c dm multipath: use updated MPATHF_QUEUE_IO on mapping for bio-based mpath 2020-05-06 08:13:29 +02:00
dm-mpath.h
dm-path-selector.c
dm-path-selector.h dm path selector: remove 'repeat_count' return from .select_path hook 2016-02-22 22:34:42 -05:00
dm-queue-length.c dm mpath selector: more evenly distribute ties 2018-01-29 13:44:58 -05:00
dm-raid.c dm raid: fix false -EBUSY when handling check/repair message 2019-12-05 09:20:37 +01:00
dm-raid1.c dm: Check for device sector overflow if CONFIG_LBDAF is not set 2019-01-26 09:32:42 +01:00
dm-region-hash.c - Error path bug fix for overflow tests (Dan) 2018-06-12 18:28:00 -07:00
dm-round-robin.c dm round robin: revert "use percpu 'repeat_count' and 'current_path'" 2017-02-17 00:54:09 -05:00
dm-rq.c blk-mq: add callback of .cleanup_rq 2019-10-05 13:10:03 +02:00
dm-rq.h dm rq: do not update rq partially in each ending bio 2017-08-28 10:23:28 -04:00
dm-service-time.c dm mpath selector: more evenly distribute ties 2018-01-29 13:44:58 -05:00
dm-snap-persistent.c block: fix an integer overflow in logical block size 2020-01-23 08:21:29 +01:00
dm-snap-transient.c dm snapshot: fix hung bios when copy error occurs 2016-01-08 20:03:05 -05:00
dm-snap.c dm snapshot: rework COW throttling to fix deadlock 2019-11-06 13:05:11 +01:00
dm-stats.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
dm-stats.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dm-stripe.c dax: Introduce a ->copy_to_iter dax operation 2018-05-22 23:18:31 -07:00
dm-switch.c treewide: Use array_size() in vmalloc() 2018-06-12 16:19:22 -07:00
dm-sysfs.c dm: move request-based code out to dm-rq.[hc] 2016-06-10 15:15:44 -04:00
dm-table.c dm table: fix invalid memory accesses with too high sector number 2019-08-29 08:28:56 +02:00
dm-target.c dm mpath: fix missing call of path selector type->end_io 2019-09-16 08:22:12 +02:00
dm-thin-metadata.c dm thin metadata: check if in fail_io mode when setting needs_check 2019-09-16 08:22:21 +02:00
dm-thin-metadata.h dm thin: fix passdown_double_checking_shared_status() 2019-01-31 08:14:38 +01:00
dm-thin.c dm thin: add sanity checks to thin-pool and external snapshot creation 2019-04-05 22:32:59 +02:00
dm-uevent.c
dm-uevent.h
dm-unstripe.c dm: Check for device sector overflow if CONFIG_LBDAF is not set 2019-01-26 09:32:42 +01:00
dm-verity-fec.c dm verity fec: fix hash block number in verity_fec_decode 2020-05-06 08:13:28 +02:00
dm-verity-fec.h dm: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
dm-verity-target.c dm verity: use message limit for data block corruption message 2019-07-21 09:03:08 +02:00
dm-verity.h dm verity: add 'check_at_most_once' option to only validate hashes once 2018-04-03 15:04:29 -04:00
dm-writecache.c dm writecache: fix data corruption when reloading the target 2020-05-06 08:13:28 +02:00
dm-zero.c dm: don't return errnos from ->map 2017-06-09 09:27:32 -06:00
dm-zoned-metadata.c dm zoned: remove duplicate nr_rnd_zones increase in dmz_init_zone() 2020-04-17 10:48:54 +02:00
dm-zoned-reclaim.c dm zoned: reduce overhead of backing device checks 2019-12-17 20:34:53 +01:00
dm-zoned-target.c dm zoned: reduce overhead of backing device checks 2019-12-17 20:34:53 +01:00
dm-zoned.h dm zoned: reduce overhead of backing device checks 2019-12-17 20:34:53 +01:00
dm.c dm: report suspended device during destroy 2020-03-11 14:15:05 +01:00
dm.h dm: move dm_table_destroy() to same header as dm_table_create() 2018-01-17 09:16:06 -05:00
Kconfig dm: add writecache target 2018-06-08 11:59:51 -04:00
Makefile dm: add writecache target 2018-06-08 11:59:51 -04:00
md-bitmap.c md/bitmap: avoid race window between md_bitmap_resize and bitmap_file_clear_bit 2019-12-31 16:35:25 +01:00
md-bitmap.h md: Avoid namespace collision with bitmap API 2018-08-01 15:49:39 -07:00
md-cluster.c md-cluster: release RESYNC lock after the last resync message 2018-08-31 17:38:10 -07:00
md-cluster.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
md-faulty.c md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
md-linear.c md: improve handling of bio with REQ_PREFLUSH in md_flush_request() 2019-12-17 20:34:55 +01:00
md-linear.h Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2017-11-14 16:07:26 -08:00
md-multipath.c md: improve handling of bio with REQ_PREFLUSH in md_flush_request() 2019-12-17 20:34:55 +01:00
md-multipath.h md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
md.c md: don't flush workqueue unconditionally in md_open 2020-06-22 09:05:17 +02:00
md.h md: improve handling of bio with REQ_PREFLUSH in md_flush_request() 2019-12-17 20:34:55 +01:00
raid1-10.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
raid1.c md: raid1: check rdev before reference in raid1_sync_request func 2020-01-09 10:18:57 +01:00
raid1.h md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
raid5-cache.c md/raid5: fix 'out of memory' during raid cache recovery 2019-02-06 17:30:16 +01:00
raid5-log.h md/raid5-cache: disable reshape completely 2018-08-31 17:38:09 -07:00
raid5-ppl.c md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
raid5.c raid5: need to set STRIPE_HANDLE for batch head 2019-12-17 20:36:00 +01:00
raid5.h Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2018-06-09 12:01:36 -07:00
raid10.c md: improve handling of bio with REQ_PREFLUSH in md_flush_request() 2019-12-17 20:34:55 +01:00
raid10.h md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
raid0.c block: fix an integer overflow in logical block size 2020-01-23 08:21:29 +01:00
raid0.h md/raid0: avoid RAID0 data corruption due to layout confusion. 2019-10-05 13:10:12 +02:00