======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kworker/1:2/789 is trying to acquire lock:
ffff8880799891f8 (kn->active#71){++++}-{0:0}, at: __kernfs_remove+0x426/0x830 fs/kernfs/dir.c:1486

but task is already holding lock:
ffffc900038bfd00 ((work_completion)(&mddev->del_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
ffffc900038bfd00 ((work_completion)(&mddev->del_work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 ((work_completion)(&mddev->del_work)){+.+.}-{0:0}:
       process_one_work kernel/workqueue.c:2633 [inline]
       process_scheduled_works+0x9ab/0x1600 kernel/workqueue.c:2734
       worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
       kthread+0x2fa/0x390 kernel/kthread.c:388
       ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
       ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

-> #3 ((wq_completion)md_misc){+.+.}-{0:0}:
       touch_wq_lockdep_map kernel/workqueue.c:3183 [inline]
       __flush_workqueue+0x169/0x1380 kernel/workqueue.c:3213
       md_alloc+0x33/0xe90 drivers/md/md.c:5831
       md_alloc_and_put+0x1a/0x1b0 drivers/md/md.c:5922
       blk_probe_dev block/genhd.c:782 [inline]
       blk_request_module+0x272/0x290 block/genhd.c:-1
       blkdev_get_no_open+0x37/0xc0 block/bdev.c:724
       blkdev_get_by_dev+0x64/0x610 block/bdev.c:782
       blkdev_open+0x14e/0x360 block/fops.c:589
       do_dentry_open+0x880/0x14b0 fs/open.c:929
       do_open fs/namei.c:3695 [inline]
       path_openat+0x284f/0x3270 fs/namei.c:3856
       do_filp_open+0x1f2/0x430 fs/namei.c:3883
       do_sys_openat2+0x134/0x1d0 fs/open.c:1422
       do_sys_open fs/open.c:1437 [inline]
       __do_sys_openat fs/open.c:1453 [inline]
       __se_sys_openat fs/open.c:1448 [inline]
       __x64_sys_openat+0x139/0x160 fs/open.c:1448
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #2 (major_names_lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x135/0xce0 kernel/locking/mutex.c:747
       blk_probe_dev block/genhd.c:779 [inline]
       blk_request_module+0x35/0x290 block/genhd.c:795
       blkdev_get_no_open+0x37/0xc0 block/bdev.c:724
       blkdev_get_by_dev+0x64/0x610 block/bdev.c:782
       md_import_device+0x398/0x7b0 drivers/md/md.c:3838
       md_add_new_disk+0x39d/0x17b0 drivers/md/md.c:6915
       md_ioctl+0x2152/0x24e0 drivers/md/md.c:7906
       blkdev_ioctl+0x5b2/0x730 block/ioctl.c:639
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:871 [inline]
       __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #1 (&mddev->reconfig_mutex){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x135/0xce0 kernel/locking/mutex.c:747
       mddev_lock drivers/md/md.h:593 [inline]
       array_state_store+0x2ef/0xb00 drivers/md/md.c:4572
       md_attr_store+0x19c/0x390 drivers/md/md.c:5756
       kernfs_fop_write_iter+0x3a4/0x520 fs/kernfs/file.c:352
       call_write_iter include/linux/fs.h:2019 [inline]
       new_sync_write fs/read_write.c:491 [inline]
       vfs_write+0x474/0x9a0 fs/read_write.c:584
       ksys_write+0x151/0x260 fs/read_write.c:637
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (kn->active#71){++++}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3162 [inline]
       check_prevs_add kernel/locking/lockdep.c:3281 [inline]
       validate_chain kernel/locking/lockdep.c:3897 [inline]
       __lock_acquire+0x3a07/0x7eb0 kernel/locking/lockdep.c:5171
       lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5790
       kernfs_drain+0x31e/0x6d0 fs/kernfs/dir.c:500
       __kernfs_remove+0x426/0x830 fs/kernfs/dir.c:1486
       kernfs_remove_by_name_ns+0xdc/0x150 fs/kernfs/dir.c:1695
       kernfs_remove_by_name include/linux/kernfs.h:624 [inline]
       remove_files fs/sysfs/group.c:28 [inline]
       sysfs_remove_group+0x101/0x290 fs/sysfs/group.c:292
       sysfs_remove_groups+0x54/0xa0 fs/sysfs/group.c:316
       __kobject_del+0x83/0x2e0 lib/kobject.c:595
       kobject_cleanup lib/kobject.c:680 [inline]
       kobject_release lib/kobject.c:720 [inline]
       kref_put include/linux/kref.h:65 [inline]
       kobject_put+0x233/0x450 lib/kobject.c:737
       process_one_work kernel/workqueue.c:2657 [inline]
       process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
       worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
       kthread+0x2fa/0x390 kernel/kthread.c:388
       ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
       ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

other info that might help us debug this:

Chain exists of:
  kn->active#71 --> (wq_completion)md_misc --> (work_completion)(&mddev->del_work)

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock((work_completion)(&mddev->del_work));
                               lock((wq_completion)md_misc);
                               lock((work_completion)(&mddev->del_work));
  lock(kn->active#71);

 *** DEADLOCK ***

2 locks held by kworker/1:2/789:
 #0: ffff88801aa80d38 ((wq_completion)md_misc){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
 #0: ffff88801aa80d38 ((wq_completion)md_misc){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
 #1: ffffc900038bfd00 ((work_completion)(&mddev->del_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
 #1: ffffc900038bfd00 ((work_completion)(&mddev->del_work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734

stack backtrace:
CPU: 1 PID: 789 Comm: kworker/1:2 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
Workqueue: md_misc mddev_delayed_delete
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 check_noncircular+0x2fc/0x400 kernel/locking/lockdep.c:2215
 check_prev_add kernel/locking/lockdep.c:3162 [inline]
 check_prevs_add kernel/locking/lockdep.c:3281 [inline]
 validate_chain kernel/locking/lockdep.c:3897 [inline]
 __lock_acquire+0x3a07/0x7eb0 kernel/locking/lockdep.c:5171
 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5790
 kernfs_drain+0x31e/0x6d0 fs/kernfs/dir.c:500
 __kernfs_remove+0x426/0x830 fs/kernfs/dir.c:1486
 kernfs_remove_by_name_ns+0xdc/0x150 fs/kernfs/dir.c:1695
 kernfs_remove_by_name include/linux/kernfs.h:624 [inline]
 remove_files fs/sysfs/group.c:28 [inline]
 sysfs_remove_group+0x101/0x290 fs/sysfs/group.c:292
 sysfs_remove_groups+0x54/0xa0 fs/sysfs/group.c:316
 __kobject_del+0x83/0x2e0 lib/kobject.c:595
 kobject_cleanup lib/kobject.c:680 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x233/0x450 lib/kobject.c:737
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>