======================================================
WARNING: possible circular locking dependency detected
5.18.0-next-20220531 #1 Not tainted
------------------------------------------------------
syz-executor.1/6051 is trying to acquire lock:
ffff888042825130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_conn_del+0x11c/0x2c0

but task is already holding lock:
ffffffff857d5468 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xc7/0x230

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (hci_cb_list_lock){+.+.}-{3:3}:
       __mutex_lock+0x136/0x14c0
       hci_remote_features_evt+0x59d/0x990
       hci_event_packet+0x779/0xee0
       hci_rx_work+0x24c/0xb90
       process_one_work+0xa1c/0x16a0
       worker_thread+0x637/0x1250
       kthread+0x2f2/0x3b0
       ret_from_fork+0x22/0x30

-> #1 (&hdev->lock){+.+.}-{3:3}:
       __mutex_lock+0x136/0x14c0
       sco_sock_connect+0x1e0/0xa60
       __sys_connect_file+0x151/0x190
       __sys_connect+0x161/0x190
       __x64_sys_connect+0x6f/0xb0
       do_syscall_64+0x3b/0x90
       entry_SYSCALL_64_after_hwframe+0x46/0xb0

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
       __lock_acquire+0x2c2f/0x6120
       lock_acquire+0x1a2/0x530
       lock_sock_nested+0x3d/0xf0
       sco_conn_del+0x11c/0x2c0
       sco_disconn_cfm+0x62/0x80
       hci_conn_hash_flush+0x119/0x230
       hci_dev_close_sync+0x4e8/0xf20
       hci_unregister_dev+0x14f/0x3e0
       vhci_release+0x7c/0xf0
       __fput+0x272/0x9d0
       task_work_run+0xe2/0x1a0
       do_exit+0xaf7/0x27e0
       do_group_exit+0xd2/0x2f0
       __x64_sys_exit_group+0x3a/0x50
       do_syscall_64+0x3b/0x90
       entry_SYSCALL_64_after_hwframe+0x46/0xb0

other info that might help us debug this:

Chain exists of:
  sk_lock-AF_BLUETOOTH-BTPROTO_SCO --> &hdev->lock --> hci_cb_list_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(hci_cb_list_lock);
                               lock(&hdev->lock);
                               lock(hci_cb_list_lock);
  lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);

 *** DEADLOCK ***

3 locks held by syz-executor.1/6051:
 #0: ffff888041355048 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x147/0x3e0
 #1: ffff888041354078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x24d/0xf20
 #2: ffffffff857d5468 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xc7/0x230

stack backtrace:
CPU: 1 PID: 6051 Comm: syz-executor.1 Not tainted 5.18.0-next-20220531 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x8b/0xb3
 check_noncircular+0x25f/0x2e0
 __lock_acquire+0x2c2f/0x6120
 lock_acquire+0x1a2/0x530
 lock_sock_nested+0x3d/0xf0
 sco_conn_del+0x11c/0x2c0
 sco_disconn_cfm+0x62/0x80
 hci_conn_hash_flush+0x119/0x230
 hci_dev_close_sync+0x4e8/0xf20
 hci_unregister_dev+0x14f/0x3e0
 vhci_release+0x7c/0xf0
 __fput+0x272/0x9d0
 task_work_run+0xe2/0x1a0
 do_exit+0xaf7/0x27e0
 do_group_exit+0xd2/0x2f0
 __x64_sys_exit_group+0x3a/0x50
 do_syscall_64+0x3b/0x90
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7fdb21681b19
Code: Unable to access opcode bytes at RIP 0x7fdb21681aef.
RSP: 002b:00007ffdb8b39048 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000034 RCX: 00007fdb21681b19
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043
RBP: 0000000000000000 R08: 0000000000000014 R09: 0000000000000034
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fdb216dc0c3
R13: 0000000000000000 R14: 0000000000000003 R15: 00007ffdb8b39230
 </TASK>
loop5: detected capacity change from 0 to 131328
Bluetooth: hci0: Opcode 0x c03 failed: -110
Bluetooth: hci0: Opcode 0x c03 failed: -110