====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kworker/0:5/4235 is trying to acquire lock: ffff8880253c5028 ((work_completion)(&hdev->bg_scan_update)){+.+.}-{0:0}, at: __flush_work+0xfa/0x210 kernel/workqueue.c:3090 but task is already holding lock: ffffffff8d6c48a8 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_epo+0x43/0x170 net/rfkill/core.c:465 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (rfkill_global_mutex){+.+.}-{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 rfkill_register+0x2f/0x970 net/rfkill/core.c:1060 hci_register_dev+0x459/0x980 net/bluetooth/hci_core.c:3987 __vhci_create_device drivers/bluetooth/hci_vhci.c:129 [inline] vhci_create_device+0x32e/0x5c0 drivers/bluetooth/hci_vhci.c:153 vhci_get_user drivers/bluetooth/hci_vhci.c:210 [inline] vhci_write+0x389/0x440 drivers/bluetooth/hci_vhci.c:290 call_write_iter include/linux/fs.h:2173 [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 -> #4 (&data->open_mutex){+.+.}-{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 vhci_send_frame+0x88/0x100 drivers/bluetooth/hci_vhci.c:71 hci_send_frame+0x1a9/0x2e0 net/bluetooth/hci_core.c:4286 hci_cmd_work+0x197/0x320 net/bluetooth/hci_core.c:5231 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 -> #3 ((work_completion)(&hdev->cmd_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 -> #2 ((wq_completion)hci0#2){+.+.}-{0:0}: flush_workqueue+0x16a/0x1390 kernel/workqueue.c:2830 drain_workqueue+0xca/0x370 kernel/workqueue.c:2995 hci_dev_do_reset net/bluetooth/hci_core.c:1917 [inline] hci_dev_reset+0x1ab/0x710 net/bluetooth/hci_core.c:1960 sock_do_ioctl+0xfb/0x320 net/socket.c:1148 sock_ioctl+0x48a/0x700 net/socket.c:1267 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 (&hdev->req_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 hci_req_sync net/bluetooth/hci_request.c:278 [inline] bg_scan_update+0x44/0x3b0 net/bluetooth/hci_request.c:2952 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 -> #0 ((work_completion)(&hdev->bg_scan_update)){+.+.}-{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 __flush_work+0x116/0x210 kernel/workqueue.c:3090 __cancel_work_timer+0x3f4/0x560 kernel/workqueue.c:3181 hci_request_cancel_all+0xcc/0x300 net/bluetooth/hci_request.c:3522 hci_dev_do_close+0x4e/0x1020 net/bluetooth/hci_core.c:1754 hci_rfkill_set_block+0x101/0x180 net/bluetooth/hci_core.c:2253 rfkill_set_block+0x1c1/0x3c0 net/rfkill/core.c:360 rfkill_epo+0x75/0x170 net/rfkill/core.c:469 __rfkill_handle_global_op net/rfkill/input.c:60 [inline] rfkill_op_handler+0x76/0x220 net/rfkill/input.c:108 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: (work_completion)(&hdev->bg_scan_update) --> &data->open_mutex --> rfkill_global_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rfkill_global_mutex); lock(&data->open_mutex); lock(rfkill_global_mutex); lock((work_completion)(&hdev->bg_scan_update)); *** DEADLOCK *** 3 locks held by kworker/0:5/4235: #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc900031afd00 ((rfkill_op_work).work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 #2: ffffffff8d6c48a8 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_epo+0x43/0x170 net/rfkill/core.c:465 stack backtrace: CPU: 0 PID: 4235 Comm: kworker/0:5 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: events rfkill_op_handler 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 __flush_work+0x116/0x210 kernel/workqueue.c:3090 __cancel_work_timer+0x3f4/0x560 kernel/workqueue.c:3181 hci_request_cancel_all+0xcc/0x300 net/bluetooth/hci_request.c:3522 hci_dev_do_close+0x4e/0x1020 net/bluetooth/hci_core.c:1754 hci_rfkill_set_block+0x101/0x180 net/bluetooth/hci_core.c:2253 rfkill_set_block+0x1c1/0x3c0 net/rfkill/core.c:360 rfkill_epo+0x75/0x170 net/rfkill/core.c:469 __rfkill_handle_global_op net/rfkill/input.c:60 [inline] rfkill_op_handler+0x76/0x220 net/rfkill/input.c:108 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