syzbot

Bluetooth: hci0: hardware error 0x00
======================================================
WARNING: possible circular locking dependency detected
6.1.84-syzkaller #0 Not tainted
------------------------------------------------------
kworker/u5:0/47 is trying to acquire lock:
ffff888018ac1130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1745 [inline]
ffff888018ac1130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_conn_del+0x104/0x300 net/bluetooth/sco.c:197

but task is already holding lock:
ffffffff8e3f02e8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1805 [inline]
ffffffff8e3f02e8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb8/0x2a0 net/bluetooth/hci_conn.c:2441

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (hci_cb_list_lock){+.+.}-{3:3}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747
       hci_connect_cfm include/net/bluetooth/hci_core.h:1790 [inline]
       hci_remote_features_evt+0x664/0xab0 net/bluetooth/hci_event.c:3778
       hci_event_func net/bluetooth/hci_event.c:7514 [inline]
       hci_event_packet+0xa9d/0x1510 net/bluetooth/hci_event.c:7566
       hci_rx_work+0x3cd/0xce0 net/bluetooth/hci_core.c:4130
       process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
       worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
       kthread+0x28d/0x320 kernel/kthread.c:376
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:307

-> #1 (&hdev->lock){+.+.}-{3:3}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747
       sco_sock_connect+0x181/0x8f0 net/bluetooth/sco.c:593
       __sys_connect_file net/socket.c:2006 [inline]
       __sys_connect+0x2c9/0x300 net/socket.c:2023
       __do_sys_connect net/socket.c:2033 [inline]
       __se_sys_connect net/socket.c:2030 [inline]
       __x64_sys_connect+0x76/0x80 net/socket.c:2030
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       lock_sock_nested+0x44/0x100 net/core/sock.c:3484
       lock_sock include/net/sock.h:1745 [inline]
       sco_conn_del+0x104/0x300 net/bluetooth/sco.c:197
       hci_disconn_cfm include/net/bluetooth/hci_core.h:1808 [inline]
       hci_conn_hash_flush+0x10e/0x2a0 net/bluetooth/hci_conn.c:2441
       hci_dev_close_sync+0x9a9/0x1020 net/bluetooth/hci_sync.c:5015
       hci_dev_do_close net/bluetooth/hci_core.c:554 [inline]
       hci_error_reset+0x12c/0x3c0 net/bluetooth/hci_core.c:1060
       process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
       worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
       kthread+0x28d/0x320 kernel/kthread.c:376
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:307

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 ***

5 locks held by kworker/u5:0/47:
 #0: ffff88807c166138 ((wq_completion)hci0){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #1: ffffc90000b87d20 ((work_completion)(&hdev->error_reset)){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #2: ffff8880239150b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:552 [inline]
 #2: ffff8880239150b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_error_reset+0x124/0x3c0 net/bluetooth/hci_core.c:1060
 #3: ffff888023914078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x48d/0x1020 net/bluetooth/hci_sync.c:5002
 #4: ffffffff8e3f02e8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1805 [inline]
 #4: ffffffff8e3f02e8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb8/0x2a0 net/bluetooth/hci_conn.c:2441

stack backtrace:
CPU: 0 PID: 47 Comm: kworker/u5:0 Not tainted 6.1.84-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: hci0 hci_error_reset
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
 lock_sock_nested+0x44/0x100 net/core/sock.c:3484
 lock_sock include/net/sock.h:1745 [inline]
 sco_conn_del+0x104/0x300 net/bluetooth/sco.c:197
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1808 [inline]
 hci_conn_hash_flush+0x10e/0x2a0 net/bluetooth/hci_conn.c:2441
 hci_dev_close_sync+0x9a9/0x1020 net/bluetooth/hci_sync.c:5015
 hci_dev_do_close net/bluetooth/hci_core.c:554 [inline]
 hci_error_reset+0x12c/0x3c0 net/bluetooth/hci_core.c:1060
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292