======================================================
WARNING: possible circular locking dependency detected
5.15.171-syzkaller #0 Not tainted
------------------------------------------------------
syz.1.27/4332 is trying to acquire lock:
ffff888025a3c120 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1678 [inline]
ffff888025a3c120 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_conn_del+0x104/0x300 net/bluetooth/sco.c:200

but task is already holding lock:
ffffffff8db7b5e8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1517 [inline]
ffffffff8db7b5e8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb8/0x220 net/bluetooth/hci_conn.c:1622

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+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       hci_connect_cfm include/net/bluetooth/hci_core.h:1502 [inline]
       hci_remote_features_evt+0x52f/0xb50 net/bluetooth/hci_event.c:3352
       hci_event_packet+0x6fe/0x1550 net/bluetooth/hci_event.c:6421
       hci_rx_work+0x232/0x990 net/bluetooth/hci_core.c:5155
       process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
       worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
       kthread+0x3f6/0x4f0 kernel/kthread.c:334
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

-> #1 (&hdev->lock){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       sco_sock_connect+0x181/0x8e0 net/bluetooth/sco.c:591
       __sys_connect_file net/socket.c:1923 [inline]
       __sys_connect+0x38b/0x410 net/socket.c:1940
       __do_sys_connect net/socket.c:1950 [inline]
       __se_sys_connect net/socket.c:1947 [inline]
       __x64_sys_connect+0x76/0x80 net/socket.c:1947
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
       __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       lock_sock_nested+0x44/0x100 net/core/sock.c:3250
       lock_sock include/net/sock.h:1678 [inline]
       sco_conn_del+0x104/0x300 net/bluetooth/sco.c:200
       hci_disconn_cfm include/net/bluetooth/hci_core.h:1520 [inline]
       hci_conn_hash_flush+0x10d/0x220 net/bluetooth/hci_conn.c:1622
       hci_dev_do_reset net/bluetooth/hci_core.c:1903 [inline]
       hci_dev_reset+0x3b9/0x650 net/bluetooth/hci_core.c:1942
       sock_do_ioctl+0x11d/0x5a0 net/socket.c:1140
       sock_ioctl+0x47f/0x770 net/socket.c:1257
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

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.1.27/4332:
 #0: ffff888075d98ff0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_reset net/bluetooth/hci_core.c:1890 [inline]
 #0: ffff888075d98ff0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_reset+0x13f/0x650 net/bluetooth/hci_core.c:1942
 #1: ffff888075d98078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_do_reset net/bluetooth/hci_core.c:1901 [inline]
 #1: ffff888075d98078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_reset+0x192/0x650 net/bluetooth/hci_core.c:1942
 #2: ffffffff8db7b5e8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1517 [inline]
 #2: ffffffff8db7b5e8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb8/0x220 net/bluetooth/hci_conn.c:1622

stack backtrace:
CPU: 0 PID: 4332 Comm: syz.1.27 Not tainted 5.15.171-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 lock_sock_nested+0x44/0x100 net/core/sock.c:3250
 lock_sock include/net/sock.h:1678 [inline]
 sco_conn_del+0x104/0x300 net/bluetooth/sco.c:200
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1520 [inline]
 hci_conn_hash_flush+0x10d/0x220 net/bluetooth/hci_conn.c:1622
 hci_dev_do_reset net/bluetooth/hci_core.c:1903 [inline]
 hci_dev_reset+0x3b9/0x650 net/bluetooth/hci_core.c:1942
 sock_do_ioctl+0x11d/0x5a0 net/socket.c:1140
 sock_ioctl+0x47f/0x770 net/socket.c:1257
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fd7e0fad719
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd7df404038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fd7e1165058 RCX: 00007fd7e0fad719
RDX: 0000000000000000 RSI: 00000000400448cb RDI: 0000000000000006
RBP: 00007fd7e102039e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fd7e1165058 R15: 00007ffceeadf558
 </TASK>