====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kworker/0:1/9 is trying to acquire lock: ffff88806016c6d0 (kn->active#67){++++}-{0:0}, at: __kernfs_remove+0x426/0x830 fs/kernfs/dir.c:1486 but task is already holding lock: ffffc900000e7d00 ((work_completion)(&mddev->del_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] ffffc900000e7d00 ((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+0x135/0xc80 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+0x518/0x17b0 drivers/md/md.c:7064 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+0x135/0xc80 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#67){++++}-{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#67 --> (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#67); *** DEADLOCK *** 2 locks held by kworker/0:1/9: #0: ffff88823bc1af38 ((wq_completion)md_misc){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #0: ffff88823bc1af38 ((wq_completion)md_misc){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #1: ffffc900000e7d00 ((work_completion)(&mddev->del_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #1: ffffc900000e7d00 ((work_completion)(&mddev->del_work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 stack backtrace: CPU: 0 PID: 9 Comm: kworker/0:1 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Workqueue: md_misc mddev_delayed_delete Call Trace: 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