R10: 0000000000000000 R11: 0000000000000213 R12: 000000002000bdc0
R13: 000000002000be00 R14: 00007f4139095000 R15: 000000002000bfc0
 </TASK>
======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc7-next-20230213 #1 Not tainted
------------------------------------------------------
kworker/0:2/58 is trying to acquire lock:
ffff888043a87130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_sock_timeout+0xc7/0x230

but task is already holding lock:
ffff88800f8cfdb0 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: process_one_work+0x941/0x1790

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}:
       __flush_work+0x109/0xd80
       __cancel_work_timer+0x39c/0x4e0
       sco_conn_del+0x1e4/0x2c0
       sco_disconn_cfm+0x66/0x80
       hci_conn_hash_flush+0x11d/0x230
       hci_dev_close_sync+0x57f/0xff0
       hci_unregister_dev+0x15e/0x410
       vhci_release+0x80/0x100
       __fput+0x263/0xa40
       task_work_run+0x174/0x280
       do_exit+0xad8/0x2800
       do_group_exit+0xd4/0x2a0
       __x64_sys_exit_group+0x3e/0x50
       do_syscall_64+0x3f/0x90
       entry_SYSCALL_64_after_hwframe+0x72/0xdc

-> #2 (hci_cb_list_lock){+.+.}-{3:3}:
       __mutex_lock+0x133/0x14a0
       hci_remote_features_evt+0x45a/0x950
       hci_event_packet+0x91d/0xf60
       hci_rx_work+0xa86/0x1110
       process_one_work+0xa0f/0x1790
       worker_thread+0x63b/0x1260
       kthread+0x2e9/0x3a0
       ret_from_fork+0x2c/0x50

-> #1 (&hdev->lock){+.+.}-{3:3}:
       __mutex_lock+0x133/0x14a0
       sco_sock_connect+0x1e8/0xa60
       __sys_connect_file+0x159/0x1a0
       __sys_connect+0x169/0x1a0
       __x64_sys_connect+0x73/0xb0
       do_syscall_64+0x3f/0x90
       entry_SYSCALL_64_after_hwframe+0x72/0xdc

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
       __lock_acquire+0x2da7/0x63b0
       lock_acquire.part.0+0xec/0x320
       lock_sock_nested+0x41/0xf0
       sco_sock_timeout+0xc7/0x230
       process_one_work+0xa0f/0x1790
       worker_thread+0x63b/0x1260
       kthread+0x2e9/0x3a0
       ret_from_fork+0x2c/0x50

other info that might help us debug this:

Chain exists of:
  sk_lock-AF_BLUETOOTH-BTPROTO_SCO --> hci_cb_list_lock --> (work_completion)(&(&conn->timeout_work)->work)

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock((work_completion)(&(&conn->timeout_work)->work));
                               lock(hci_cb_list_lock);
                               lock((work_completion)(&(&conn->timeout_work)->work));
  lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);

 *** DEADLOCK ***

2 locks held by kworker/0:2/58:
 #0: ffff888008468d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x90d/0x1790
 #1: ffff88800f8cfdb0 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: process_one_work+0x941/0x1790

stack backtrace:
CPU: 0 PID: 58 Comm: kworker/0:2 Not tainted 6.2.0-rc7-next-20230213 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Workqueue: events sco_sock_timeout
Call Trace:
 <TASK>
 dump_stack_lvl+0x91/0xf0
 check_noncircular+0x263/0x2e0
 __lock_acquire+0x2da7/0x63b0
 lock_acquire.part.0+0xec/0x320
 lock_sock_nested+0x41/0xf0
 sco_sock_timeout+0xc7/0x230
 process_one_work+0xa0f/0x1790
 worker_thread+0x63b/0x1260
 kthread+0x2e9/0x3a0
 ret_from_fork+0x2c/0x50
 </TASK>