======================================================
WARNING: possible circular locking dependency detected
6.1.0-syzkaller-03225-g764822972d64 #0 Not tainted
------------------------------------------------------
syz-executor.3/12078 is trying to acquire lock:
ffff888077ee5670 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: __flush_work+0xdd/0xaf0 kernel/workqueue.c:3066

but task is already holding lock:
ffffffff8e0d93c8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1784 [inline]
ffffffff8e0d93c8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xd9/0x260 net/bluetooth/hci_conn.c:2436

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (hci_cb_list_lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x12f/0x1360 kernel/locking/mutex.c:747
       hci_connect_cfm include/net/bluetooth/hci_core.h:1769 [inline]
       hci_remote_features_evt+0x49e/0xa20 net/bluetooth/hci_event.c:3758
       hci_event_func net/bluetooth/hci_event.c:7472 [inline]
       hci_event_packet+0x956/0xfd0 net/bluetooth/hci_event.c:7524
       hci_rx_work+0xaeb/0x1230 net/bluetooth/hci_core.c:4043
       process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
       worker_thread+0x669/0x1090 kernel/workqueue.c:2436
       kthread+0x2e8/0x3a0 kernel/kthread.c:376
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

-> #2 (&hdev->lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x12f/0x1360 kernel/locking/mutex.c:747
       sco_sock_connect+0x1ea/0xa60 net/bluetooth/sco.c:593
       __sys_connect_file+0x153/0x1a0 net/socket.c:1976
       __sys_connect+0x165/0x1a0 net/socket.c:1993
       __do_sys_connect net/socket.c:2003 [inline]
       __se_sys_connect net/socket.c:2000 [inline]
       __x64_sys_connect+0x73/0xb0 net/socket.c:2000
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
       lock_sock_nested+0x3a/0xf0 net/core/sock.c:3447
       lock_sock include/net/sock.h:1721 [inline]
       sco_sock_timeout+0xd1/0x290 net/bluetooth/sco.c:97
       process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
       worker_thread+0x669/0x1090 kernel/workqueue.c:2436
       kthread+0x2e8/0x3a0 kernel/kthread.c:376
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

-> #0 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3097 [inline]
       check_prevs_add kernel/locking/lockdep.c:3216 [inline]
       validate_chain kernel/locking/lockdep.c:3831 [inline]
       __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055
       lock_acquire kernel/locking/lockdep.c:5668 [inline]
       lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
       __flush_work+0x109/0xaf0 kernel/workqueue.c:3069
       __cancel_work_timer+0x3f9/0x570 kernel/workqueue.c:3160
       sco_conn_del+0x1b5/0x2b0 net/bluetooth/sco.c:205
       sco_disconn_cfm+0x75/0xb0 net/bluetooth/sco.c:1379
       hci_disconn_cfm include/net/bluetooth/hci_core.h:1787 [inline]
       hci_conn_hash_flush+0x126/0x260 net/bluetooth/hci_conn.c:2436
       hci_dev_close_sync+0x5fb/0x1200 net/bluetooth/hci_sync.c:4831
       hci_dev_do_close+0x31/0x70 net/bluetooth/hci_core.c:554
       hci_rfkill_set_block+0x161/0x1d0 net/bluetooth/hci_core.c:956
       rfkill_set_block+0x1f9/0x540 net/rfkill/core.c:345
       rfkill_fop_write+0x2c7/0x570 net/rfkill/core.c:1286
       vfs_write+0x2db/0xdd0 fs/read_write.c:582
       ksys_write+0x1ec/0x250 fs/read_write.c:637
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
  (work_completion)(&(&conn->timeout_work)->work) --> &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((work_completion)(&(&conn->timeout_work)->work));

 *** DEADLOCK ***

4 locks held by syz-executor.3/12078:
 #0: ffffffff8e2ceb68 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0x160/0x570 net/rfkill/core.c:1278
 #1: ffff88807db21028 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x29/0x70 net/bluetooth/hci_core.c:552
 #2: ffff88807db20078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x306/0x1200 net/bluetooth/hci_sync.c:4818
 #3: ffffffff8e0d93c8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1784 [inline]
 #3: ffffffff8e0d93c8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xd9/0x260 net/bluetooth/hci_conn.c:2436

stack backtrace:
CPU: 0 PID: 12078 Comm: syz-executor.3 Not tainted 6.1.0-syzkaller-03225-g764822972d64 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2177
 check_prev_add kernel/locking/lockdep.c:3097 [inline]
 check_prevs_add kernel/locking/lockdep.c:3216 [inline]
 validate_chain kernel/locking/lockdep.c:3831 [inline]
 __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055
 lock_acquire kernel/locking/lockdep.c:5668 [inline]
 lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
 __flush_work+0x109/0xaf0 kernel/workqueue.c:3069
 __cancel_work_timer+0x3f9/0x570 kernel/workqueue.c:3160
 sco_conn_del+0x1b5/0x2b0 net/bluetooth/sco.c:205
 sco_disconn_cfm+0x75/0xb0 net/bluetooth/sco.c:1379
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1787 [inline]
 hci_conn_hash_flush+0x126/0x260 net/bluetooth/hci_conn.c:2436
 hci_dev_close_sync+0x5fb/0x1200 net/bluetooth/hci_sync.c:4831
 hci_dev_do_close+0x31/0x70 net/bluetooth/hci_core.c:554
 hci_rfkill_set_block+0x161/0x1d0 net/bluetooth/hci_core.c:956
 rfkill_set_block+0x1f9/0x540 net/rfkill/core.c:345
 rfkill_fop_write+0x2c7/0x570 net/rfkill/core.c:1286
 vfs_write+0x2db/0xdd0 fs/read_write.c:582
 ksys_write+0x1ec/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f892c28c0d9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f892d08e168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f892c3abf80 RCX: 00007f892c28c0d9
RDX: 0000000000000008 RSI: 0000000020000040 RDI: 0000000000000003
RBP: 00007f892c2e7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc622a908f R14: 00007f892d08e300 R15: 0000000000022000
 </TASK>