====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kworker/1:15/4541 is trying to acquire lock: ffff888075af9578 (kn->active#506){++++}-{0:0}, at: kernfs_remove+0x1d/0x30 fs/kernfs/dir.c:1406 but task is already holding lock: ffffc9000455fd00 ((work_completion)(&mddev->del_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 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+0x7ba/0xff0 kernel/workqueue.c:2286 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #3 ((wq_completion)md_misc){+.+.}-{0:0}: flush_workqueue+0x16a/0x1390 kernel/workqueue.c:2830 md_alloc+0x2e/0xc10 drivers/md/md.c:5720 blk_probe_dev block/genhd.c:685 [inline] blk_request_module+0x26e/0x290 block/genhd.c:-1 blkdev_get_no_open+0x38/0x1d0 block/bdev.c:736 blkdev_get_by_dev+0x77/0xa50 block/bdev.c:803 blkdev_open+0x128/0x2c0 block/fops.c:466 do_dentry_open+0x7f7/0xf90 fs/open.c:826 do_open fs/namei.c:3659 [inline] path_openat+0x2718/0x2fb0 fs/namei.c:3793 do_filp_open+0x1df/0x400 fs/namei.c:3820 do_sys_openat2+0x14b/0x500 fs/open.c:1255 do_sys_open fs/open.c:1271 [inline] __do_sys_openat fs/open.c:1287 [inline] __se_sys_openat fs/open.c:1282 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1282 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #2 (major_names_lock){+.+.}-{3:3}: __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 blk_probe_dev block/genhd.c:682 [inline] blk_request_module+0x31/0x290 block/genhd.c:698 blkdev_get_no_open+0x38/0x1d0 block/bdev.c:736 blkdev_get_by_dev+0x77/0xa50 block/bdev.c:803 lock_rdev drivers/md/md.c:2576 [inline] md_import_device+0x3e2/0x810 drivers/md/md.c:3774 md_add_new_disk+0x3fa/0x1960 drivers/md/md.c:6790 md_ioctl+0x236f/0x26f0 drivers/md/md.c:7770 blkdev_ioctl+0x347/0x6f0 block/ioctl.c:604 block_ioctl+0xac/0xf0 block/fops.c:496 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #1 (&mddev->reconfig_mutex){+.+.}-{3:3}: __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_interruptible_nested+0x17/0x20 kernel/locking/mutex.c:765 mddev_lock drivers/md/md.h:543 [inline] new_dev_store+0x222/0x660 drivers/md/md.c:4664 md_attr_store+0xdd/0x130 drivers/md/md.c:5636 kernfs_fop_write_iter+0x3a8/0x500 fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:2179 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x748/0xd70 fs/read_write.c:594 ksys_write+0x153/0x260 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #0 (kn->active#506){++++}-{0:0}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c66/0x7b50 kernel/locking/lockdep.c:5012 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623 kernfs_drain fs/kernfs/dir.c:478 [inline] __kernfs_remove+0x5da/0xcb0 fs/kernfs/dir.c:1372 kernfs_remove+0x1d/0x30 fs/kernfs/dir.c:1406 __kobject_del+0xe0/0x2e0 lib/kobject.c:628 kobject_del+0x41/0x60 lib/kobject.c:651 mddev_delayed_delete+0x27/0x30 drivers/md/md.c:5678 process_one_work+0x867/0xff0 kernel/workqueue.c:2310 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 other info that might help us debug this: Chain exists of: kn->active#506 --> (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#506); *** DEADLOCK *** 2 locks held by kworker/1:15/4541: #0: ffff888017a7e938 ((wq_completion)md_misc){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc9000455fd00 ((work_completion)(&mddev->del_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 stack backtrace: CPU: 1 PID: 4541 Comm: kworker/1:15 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: md_misc mddev_delayed_delete Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c66/0x7b50 kernel/locking/lockdep.c:5012 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623 kernfs_drain fs/kernfs/dir.c:478 [inline] __kernfs_remove+0x5da/0xcb0 fs/kernfs/dir.c:1372 kernfs_remove+0x1d/0x30 fs/kernfs/dir.c:1406 __kobject_del+0xe0/0x2e0 lib/kobject.c:628 kobject_del+0x41/0x60 lib/kobject.c:651 mddev_delayed_delete+0x27/0x30 drivers/md/md.c:5678 process_one_work+0x867/0xff0 kernel/workqueue.c:2310 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287