[   14.711344] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[   14.713505] Bluetooth: BNEP socket layer initialized
[   14.714497] Bluetooth: RFCOMM TTY layer initialized
[   14.714511] Bluetooth: RFCOMM socket layer initialized
[   14.714512] Bluetooth: RFCOMM ver 1.11
[   15.385668] input: ACPI Virtual Keyboard Device as /devices/virtual/input/input17
[   57.826528] PPP generic driver version 2.4.2
[   66.309295] 
[   66.309301] ======================================================
[   66.309303] [ INFO: possible circular locking dependency detected ]
[   66.309307] 3.7.0 #195 Not tainted
[   66.309308] -------------------------------------------------------
[   66.309310] kworker/2:1/35 is trying to acquire lock:
[   66.309313]  (&tty->legacy_mutex){+.+.+.}, at: [<c150f286>] tty_lock_nested+0x36/0x80
[   66.309328] 
[   66.309328] but task is already holding lock:
[   66.309330]  ((&tty->hangup_work)){+.+...}, at: [<c1052983>] process_one_work+0x123/0x4d0
[   66.309340] 
[   66.309340] which lock already depends on the new lock.
[   66.309340] 
[   66.309343] 
[   66.309343] the existing dependency chain (in reverse order) is:
[   66.309345] 
[   66.309345] -> #2 ((&tty->hangup_work)){+.+...}:
[   66.309351]        [<c1085809>] lock_acquire+0x79/0xf0
[   66.309357]        [<c1053168>] flush_work+0x48/0x250
[   66.309360]        [<c1294a56>] tty_ldisc_flush_works+0x16/0x30
[   66.309366]        [<c1295941>] tty_ldisc_release+0x21/0x70
[   66.309370]        [<c128ee7c>] tty_release+0x37c/0x4a0
[   66.309376]        [<c11175cc>] __fput+0xcc/0x1f0
[   66.309381]        [<c11176fd>] ____fput+0xd/0x10
[   66.309385]        [<c1056eb9>] task_work_run+0x89/0xa0
[   66.309390]        [<c1002b11>] do_notify_resume+0x51/0x80
[   66.309394]        [<c150f578>] work_notifysig+0x29/0x31
[   66.309399] 
[   66.309399] -> #1 (&tty->legacy_mutex/1){+.+...}:
[   66.309405]        [<c1085809>] lock_acquire+0x79/0xf0
[   66.309409]        [<c150c1fa>] mutex_lock_nested+0x4a/0x2f0
[   66.309413]        [<c150f286>] tty_lock_nested+0x36/0x80
[   66.309417]        [<c150f319>] tty_lock_pair+0x29/0x70
[   66.309421]        [<c128ec30>] tty_release+0x130/0x4a0
[   66.309425]        [<c11175cc>] __fput+0xcc/0x1f0
[   66.309429]        [<c11176fd>] ____fput+0xd/0x10
[   66.309432]        [<c1056eb9>] task_work_run+0x89/0xa0
[   66.309436]        [<c1002b11>] do_notify_resume+0x51/0x80
[   66.309440]        [<c150f578>] work_notifysig+0x29/0x31
[   66.309444] 
[   66.309444] -> #0 (&tty->legacy_mutex){+.+.+.}:
[   66.309448]        [<c10852ae>] __lock_acquire+0x165e/0x1710
[   66.309453]        [<c1085809>] lock_acquire+0x79/0xf0
[   66.309456]        [<c150c1fa>] mutex_lock_nested+0x4a/0x2f0
[   66.309460]        [<c150f286>] tty_lock_nested+0x36/0x80
[   66.309464]        [<c150f2df>] tty_lock+0xf/0x20
[   66.309468]        [<c128d904>] __tty_hangup+0x54/0x430
[   66.309472]        [<c128dcf2>] do_tty_hangup+0x12/0x20
[   66.309476]        [<c1052a02>] process_one_work+0x1a2/0x4d0
[   66.309480]        [<c1054509>] worker_thread+0x119/0x3b0
[   66.309484]        [<c105a1ff>] kthread+0x9f/0xb0
[   66.309488]        [<c150fc37>] ret_from_kernel_thread+0x1b/0x28
[   66.309492] 
[   66.309492] other info that might help us debug this:
[   66.309492] 
[   66.309495] Chain exists of:
[   66.309495]   &tty->legacy_mutex --> &tty->legacy_mutex/1 --> (&tty->hangup_work)
[   66.309495] 
[   66.309502]  Possible unsafe locking scenario:
[   66.309502] 
[   66.309504]        CPU0                    CPU1
[   66.309506]        ----                    ----
[   66.309507]   lock((&tty->hangup_work));
[   66.309510]                                lock(&tty->legacy_mutex/1);
[   66.309514]                                lock((&tty->hangup_work));
[   66.309517]   lock(&tty->legacy_mutex);
[   66.309520] 
[   66.309520]  *** DEADLOCK ***
[   66.309520] 
[   66.309524] 2 locks held by kworker/2:1/35:
[   66.309525]  #0:  (events){.+.+.+}, at: [<c1052983>] process_one_work+0x123/0x4d0
[   66.309532]  #1:  ((&tty->hangup_work)){+.+...}, at: [<c1052983>] process_one_work+0x123/0x4d0
[   66.309539] 
[   66.309539] stack backtrace:
[   66.309543] Pid: 35, comm: kworker/2:1 Not tainted 3.7.0 #195
[   66.309545] Call Trace:
[   66.309552]  [<c1506992>] print_circular_bug+0x1af/0x1b9
[   66.309556]  [<c10852ae>] __lock_acquire+0x165e/0x1710
[   66.309562]  [<c1085809>] lock_acquire+0x79/0xf0
[   66.309566]  [<c150f286>] ? tty_lock_nested+0x36/0x80
[   66.309571]  [<c150c1fa>] mutex_lock_nested+0x4a/0x2f0
[   66.309575]  [<c150f286>] ? tty_lock_nested+0x36/0x80
[   66.309579]  [<c128d8d2>] ? __tty_hangup+0x22/0x430
[   66.309583]  [<c150f286>] tty_lock_nested+0x36/0x80
[   66.309588]  [<c150f2df>] tty_lock+0xf/0x20
[   66.309592]  [<c128d904>] __tty_hangup+0x54/0x430
[   66.309596]  [<c1052983>] ? process_one_work+0x123/0x4d0
[   66.309600]  [<c128dcf2>] do_tty_hangup+0x12/0x20
[   66.309604]  [<c1052a02>] process_one_work+0x1a2/0x4d0
[   66.309607]  [<c1052983>] ? process_one_work+0x123/0x4d0
[   66.309611]  [<c10545ae>] ? worker_thread+0x1be/0x3b0
[   66.309616]  [<c128dce0>] ? __tty_hangup+0x430/0x430
[   66.309620]  [<c1054509>] worker_thread+0x119/0x3b0
[   66.309624]  [<c10543f0>] ? __next_gcwq_cpu+0x60/0x60
[   66.309628]  [<c105a1ff>] kthread+0x9f/0xb0
[   66.309633]  [<c150fc37>] ret_from_kernel_thread+0x1b/0x28
[   66.309637]  [<c105a160>] ? kthread_create_on_node+0xe0/0xe0