====================================================== WARNING: possible circular locking dependency detected 6.6.0-syzkaller-15866-g2bd5b559a1f3 #0 Not tainted ------------------------------------------------------ syz-executor.0/5092 is trying to acquire lock: ffff88804a19cae0 ((work_completion)(&(&hdev->discov_off)->work)){+.+.}-{0:0}, at: __flush_work+0xfa/0xa10 kernel/workqueue.c:3403 but task is already holding lock: ffff88804a19c078 (&hdev->lock){+.+.}-{3:3}, at: hci_unregister_dev+0x46a/0x600 net/bluetooth/hci_core.c:2744 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&hdev->lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x181/0x1340 kernel/locking/mutex.c:747 discov_off+0x8c/0x1d0 net/bluetooth/mgmt.c:1055 process_one_work+0x884/0x15c0 kernel/workqueue.c:2630 process_scheduled_works kernel/workqueue.c:2703 [inline] worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784 kthread+0x33c/0x440 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 -> #0 ((work_completion)(&(&hdev->discov_off)->work)){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3868 [inline] __lock_acquire+0x2e3d/0x5de0 kernel/locking/lockdep.c:5136 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718 __flush_work+0x103/0xa10 kernel/workqueue.c:3403 __cancel_work_timer+0x3ef/0x580 kernel/workqueue.c:3494 mgmt_index_removed+0x1ed/0x350 net/bluetooth/mgmt.c:9436 hci_unregister_dev+0x472/0x600 net/bluetooth/hci_core.c:2745 vhci_release+0x7f/0x100 drivers/bluetooth/hci_vhci.c:672 __fput+0x270/0xbb0 fs/file_table.c:394 task_work_run+0x14d/0x240 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa92/0x2ae0 kernel/exit.c:871 do_group_exit+0xd4/0x2a0 kernel/exit.c:1021 __do_sys_exit_group kernel/exit.c:1032 [inline] __se_sys_exit_group kernel/exit.c:1030 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1030 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&hdev->lock); lock((work_completion)(&(&hdev->discov_off)->work)); lock(&hdev->lock); lock((work_completion)(&(&hdev->discov_off)->work)); *** DEADLOCK *** 1 lock held by syz-executor.0/5092: #0: ffff88804a19c078 (&hdev->lock){+.+.}-{3:3}, at: hci_unregister_dev+0x46a/0x600 net/bluetooth/hci_core.c:2744 stack backtrace: CPU: 0 PID: 5092 Comm: syz-executor.0 Not tainted 6.6.0-syzkaller-15866-g2bd5b559a1f3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 check_noncircular+0x311/0x3f0 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3868 [inline] __lock_acquire+0x2e3d/0x5de0 kernel/locking/lockdep.c:5136 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718 __flush_work+0x103/0xa10 kernel/workqueue.c:3403 __cancel_work_timer+0x3ef/0x580 kernel/workqueue.c:3494 mgmt_index_removed+0x1ed/0x350 net/bluetooth/mgmt.c:9436 hci_unregister_dev+0x472/0x600 net/bluetooth/hci_core.c:2745 vhci_release+0x7f/0x100 drivers/bluetooth/hci_vhci.c:672 __fput+0x270/0xbb0 fs/file_table.c:394 task_work_run+0x14d/0x240 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa92/0x2ae0 kernel/exit.c:871 do_group_exit+0xd4/0x2a0 kernel/exit.c:1021 __do_sys_exit_group kernel/exit.c:1032 [inline] __se_sys_exit_group kernel/exit.c:1030 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1030 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7fd3f7a7cae9 Code: Unable to access opcode bytes at 0x7fd3f7a7cabf. RSP: 002b:00007fff8e925938 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 00007fd3f7a7cae9 RDX: 00007fd3f7a7e83a RSI: 0000000000000000 RDI: 0000000000000007 RBP: 0000000000000003 R08: 0079746972756365 R09: 0000000000000007 R10: 00000000000003b8 R11: 0000000000000246 R12: 00007fd3f7b78640 R13: 00007fff8e925f3c R14: 0000000000000000 R15: 00007fd3f7b78d00 bridge0: port 1(syz_tun) entered disabled state syz_tun (unregistering): left allmulticast mode syz_tun (unregistering): left promiscuous mode bridge0: port 1(syz_tun) entered disabled state