====================================================== WARNING: possible circular locking dependency detected 5.15.173-syzkaller #0 Not tainted ------------------------------------------------------ kworker/0:8/4241 is trying to acquire lock: ffff888025d58b98 ((work_completion)(&hdev->tx_work)){+.+.}-{0:0}, at: __flush_work+0xcf/0x1a0 kernel/workqueue.c:3090 but task is already holding lock: ffff888025d58ff0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x63/0x1070 net/bluetooth/hci_core.c:1737 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&hdev->req_lock){+.+.}-{3:3}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 hci_dev_do_close+0x63/0x1070 net/bluetooth/hci_core.c:1737 hci_rfkill_set_block+0x114/0x1a0 net/bluetooth/hci_core.c:2235 rfkill_set_block+0x1e7/0x430 net/rfkill/core.c:345 rfkill_epo+0x7c/0x180 net/rfkill/core.c:454 __rfkill_handle_global_op net/rfkill/input.c:60 [inline] rfkill_op_handler+0x7e/0x260 net/rfkill/input.c:108 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #2 (rfkill_global_mutex){+.+.}-{3:3}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __mutex_lock_common+0x1da/0x25a0 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+0x30/0x880 net/rfkill/core.c:1045 hci_register_dev+0x4dd/0xa50 net/bluetooth/hci_core.c:3960 __vhci_create_device drivers/bluetooth/hci_vhci.c:129 [inline] vhci_create_device+0x310/0x590 drivers/bluetooth/hci_vhci.c:153 vhci_get_user drivers/bluetooth/hci_vhci.c:210 [inline] vhci_write+0x382/0x430 drivers/bluetooth/hci_vhci.c:290 call_write_iter include/linux/fs.h:2174 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0xacd/0xe50 fs/read_write.c:594 ksys_write+0x1a2/0x2c0 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #1 (&data->open_mutex){+.+.}-{3:3}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __mutex_lock_common+0x1da/0x25a0 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+0x8a/0xf0 drivers/bluetooth/hci_vhci.c:71 hci_send_frame+0x1af/0x2f0 net/bluetooth/hci_core.c:4256 hci_sched_acl_pkt net/bluetooth/hci_core.c:4781 [inline] hci_sched_acl net/bluetooth/hci_core.c:4866 [inline] hci_tx_work+0xb2e/0x1a30 net/bluetooth/hci_core.c:4932 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #0 ((work_completion)(&hdev->tx_work)){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __flush_work+0xeb/0x1a0 kernel/workqueue.c:3090 hci_dev_do_close+0x20a/0x1070 net/bluetooth/hci_core.c:1756 hci_rfkill_set_block+0x114/0x1a0 net/bluetooth/hci_core.c:2235 rfkill_set_block+0x1e7/0x430 net/rfkill/core.c:345 rfkill_epo+0x7c/0x180 net/rfkill/core.c:454 __rfkill_handle_global_op net/rfkill/input.c:60 [inline] rfkill_op_handler+0x7e/0x260 net/rfkill/input.c:108 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457 kthread+0x3f6/0x4f0 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->tx_work) --> rfkill_global_mutex --> &hdev->req_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&hdev->req_lock); lock(rfkill_global_mutex); lock(&hdev->req_lock); lock((work_completion)(&hdev->tx_work)); *** DEADLOCK *** 4 locks held by kworker/0:8/4241: #0: ffff888017070938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283 #1: ffffc90004027d20 ((rfkill_op_work).work){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285 #2: ffffffff8dcbe668 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_epo+0x47/0x180 net/rfkill/core.c:450 #3: ffff888025d58ff0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x63/0x1070 net/bluetooth/hci_core.c:1737 stack backtrace: CPU: 0 PID: 4241 Comm: kworker/0:8 Not tainted 5.15.173-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024 Workqueue: events rfkill_op_handler Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 check_noncircular+0x2f8/0x3b0 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+0x1649/0x5930 kernel/locking/lockdep.c:3788 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __flush_work+0xeb/0x1a0 kernel/workqueue.c:3090 hci_dev_do_close+0x20a/0x1070 net/bluetooth/hci_core.c:1756 hci_rfkill_set_block+0x114/0x1a0 net/bluetooth/hci_core.c:2235 rfkill_set_block+0x1e7/0x430 net/rfkill/core.c:345 rfkill_epo+0x7c/0x180 net/rfkill/core.c:454 __rfkill_handle_global_op net/rfkill/input.c:60 [inline] rfkill_op_handler+0x7e/0x260 net/rfkill/input.c:108 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287