Hi Bastien,
> During my testing trying to pair the new XBox One S Bluetooth
> controller, I hit a lockdep warning.
>
> [ 56.415138] ============================================
> [ 56.415139] WARNING: possible recursive locking detected
> [ 56.415142] 4.14.0-0.rc8.git1.1.bt2.fc28.x86_64 #1 Not tainted
> [ 56.415143] --------------------------------------------
> [ 56.415145] kworker/u9:2/579 is trying to acquire lock:
> [ 56.415147] (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}, at: [<ffffffffc08dc262>] bt_accept_enqueue+0x42/0xc0 [bluetooth]
> [ 56.415167]
> but task is already holding lock:
> [ 56.415168] (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}, at: [<ffffffffc0919e5d>] l2cap_sock_new_connection_cb+0x1d/0xa0 [bluetooth]
> [ 56.415184]
> other info that might help us debug this:
> [ 56.415186] Possible unsafe locking scenario:
>
> [ 56.415187] CPU0
> [ 56.415188] ----
> [ 56.415189] lock(sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP);
> [ 56.415192] lock(sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP);
> [ 56.415194]
> *** DEADLOCK ***
>
> [ 56.415196] May be due to missing lock nesting notation
>
> [ 56.415198] 5 locks held by kworker/u9:2/579:
> [ 56.415199] #0: ("%s"hdev->name#2){+.+.}, at: [<ffffffffae0d4e90>] process_one_work+0x1d0/0x6a0
> [ 56.415206] #1: ((&hdev->rx_work)){+.+.}, at: [<ffffffffae0d4e90>] process_one_work+0x1d0/0x6a0
> [ 56.415211] #2: (&conn->chan_lock){+.+.}, at: [<ffffffffc09120e3>] l2cap_connect+0x93/0x5d0 [bluetooth]
> [ 56.415226] #3: (&chan->lock/2){+.+.}, at: [<ffffffffc09120fd>] l2cap_connect+0xad/0x5d0 [bluetooth]
> [ 56.415239] #4: (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}, at: [<ffffffffc0919e5d>] l2cap_sock_new_connection_cb+0x1d/0xa0 [bluetooth]
> [ 56.415252]
> stack backtrace:
> [ 56.415255] CPU: 0 PID: 579 Comm: kworker/u9:2 Not tainted 4.14.0-0.rc8.git1.1.bt2.fc28.x86_64 #1
> [ 56.415257] Hardware name: Dell Inc. OptiPlex 9020M/0Y5DDC, BIOS A07 09/10/2015
> [ 56.415267] Workqueue: hci0 hci_rx_work [bluetooth]
> [ 56.415269] Call Trace:
> [ 56.415274] dump_stack+0x8e/0xd6
> [ 56.415279] __lock_acquire+0x6af/0x1320
> [ 56.415288] ? bt_accept_enqueue+0x42/0xc0 [bluetooth]
> [ 56.415291] ? __lock_is_held+0x65/0xb0
> [ 56.415294] ? mark_held_locks+0x5f/0x90
> [ 56.415299] lock_acquire+0xa3/0x1f0
> [ 56.415301] ? lock_acquire+0xa3/0x1f0
> [ 56.415310] ? bt_accept_enqueue+0x42/0xc0 [bluetooth]
> [ 56.415314] lock_sock_nested+0x76/0xa0
> [ 56.415323] ? bt_accept_enqueue+0x42/0xc0 [bluetooth]
> [ 56.415332] bt_accept_enqueue+0x42/0xc0 [bluetooth]
> [ 56.415343] l2cap_sock_new_connection_cb+0x62/0xa0 [bluetooth]
> [ 56.415353] l2cap_connect+0x136/0x5d0 [bluetooth]
> [ 56.415358] ? sched_clock+0x9/0x10
> [ 56.415368] ? l2cap_recv_frame+0x7a6/0x2900 [bluetooth]
> [ 56.415373] ? __mutex_unlock_slowpath+0x50/0x2f0
> [ 56.415383] l2cap_recv_frame+0x7be/0x2900 [bluetooth]
> [ 56.415393] ? hci_rx_work+0x472/0x5f0 [bluetooth]
> [ 56.415404] l2cap_recv_acldata+0x2ff/0x310 [bluetooth]
> [ 56.415413] hci_rx_work+0x494/0x5f0 [bluetooth]
> [ 56.415417] process_one_work+0x250/0x6a0
> [ 56.415421] worker_thread+0x3d/0x3b0
> [ 56.415424] kthread+0x133/0x150
> [ 56.415426] ? process_one_work+0x6a0/0x6a0
> [ 56.415428] ? kthread_create_on_node+0x70/0x70
> [ 56.415431] ret_from_fork+0x2a/0x40
if you run mgmt-tester or smp-tester, do you get the same lockdep warning. And is the BR/EDR or LE connection?
Regards
Marcel
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