Hey, 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 -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html