====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kworker/0:1/13 is trying to acquire lock: ffff88805c0b8490 (kn->active#755){++++}-{0:0}, at: kernfs_remove+0x1d/0x30 fs/kernfs/dir.c:1406 but task is already holding lock: ffffc90000d27d00 ((work_completion)(&rdev->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)(&rdev->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_rdev_misc){+.+.}-{0:0}: flush_workqueue+0x16a/0x1390 kernel/workqueue.c:2830 md_alloc+0x3a/0xc10 drivers/md/md.c:5728 blk_probe_dev block/genhd.c:692 [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:689 [inline] blk_request_module+0x31/0x290 block/genhd.c:705 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:2583 [inline] md_import_device+0x3e2/0x810 drivers/md/md.c:3781 md_add_new_disk+0x6cd/0x1960 drivers/md/md.c:-1 md_ioctl+0x1ff1/0x26f0 drivers/md/md.c:7739 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] rdev_attr_store+0xa1/0x180 drivers/md/md.c:3701 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#755){++++}-{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:5625 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 rdev_delayed_delete+0x18/0x30 drivers/md/md.c:2542 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#755 --> (wq_completion)md_rdev_misc --> (work_completion)(&rdev->del_work) Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock((work_completion)(&rdev->del_work)); lock((wq_completion)md_rdev_misc); lock((work_completion)(&rdev->del_work) ); lock(kn->active#755); *** DEADLOCK *** 2 locks held by kworker/0:1/13: #0: ffff88801bcf1138 ((wq_completion)md_rdev_misc ){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc90000d27d00 ((work_completion)(&rdev->del_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 stack backtrace: CPU: 0 PID: 13 Comm: kworker/0:1 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: md_rdev_misc rdev_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:5625 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 rdev_delayed_delete+0x18/0x30 drivers/md/md.c:2542 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 kobject: 'dev-ram0' (ffff888028a5b078): kobject_cleanup, parent 0000000000000000 kobject: 'dev-ram0' (ffff888028a5b078): calling ktype release kobject: 'dev-ram0': free name Added buffer head 0 to ffff88801e7b1900 nf_conntrack: normal packet for ffff88807cfcea80 nf_conntrack: normal packet for ffff888022fe5b00 nf_conntrack: normal packet for ffff88807cfcf680 Added buffer head 0 to ffff88801e7b1900 nf_conntrack: normal packet for ffff888022fe4a80 nf_conntrack: normal packet for ffff88805ad50780 Added buffer head 0 to ffff88801e7b1900 Added buffer head 0 to ffff88801e7b1900 nf_conntrack: normal packet for ffff888022fe4a80 nf_conntrack: normal packet for ffff88807cfcf680 nf_conntrack: normal packet for ffff88807cfcea80 Added buffer head 0 to ffff88801e7b1900