syzbot

============================================
WARNING: possible recursive locking detected
5.18.0-syzkaller-02752-gfdaf9a5840ac #0 Not tainted
--------------------------------------------
syz-executor372/3606 is trying to acquire lock:
ffff888016db5130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1682 [inline]
ffff888016db5130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sk_state_change+0x52/0x2f0 net/bluetooth/rfcomm/sock.c:73

but task is already holding lock:
ffff888016db5130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1682 [inline]
ffff888016db5130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sock_shutdown+0x51/0x220 net/bluetooth/rfcomm/sock.c:902

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM);
  lock(sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

4 locks held by syz-executor372/3606:
 #0: ffff88807249ca10 (&sb->s_type->i_mutex_key#9){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:732 [inline]
 #0: ffff88807249ca10 (&sb->s_type->i_mutex_key#9){+.+.}-{3:3}, at: __sock_release net/socket.c:649 [inline]
 #0: ffff88807249ca10 (&sb->s_type->i_mutex_key#9){+.+.}-{3:3}, at: sock_close+0x93/0x260 net/socket.c:1318
 #1: ffff888016db5130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1682 [inline]
 #1: ffff888016db5130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sock_shutdown+0x51/0x220 net/bluetooth/rfcomm/sock.c:902
 #2: ffffffff8dd24508 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_close+0x32/0x1c0 net/bluetooth/rfcomm/core.c:507
 #3: ffff888020d3c128 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x276/0x470 net/bluetooth/rfcomm/core.c:487

stack backtrace:
CPU: 1 PID: 3606 Comm: syz-executor372 Not tainted 5.18.0-syzkaller-02752-gfdaf9a5840ac #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_deadlock_bug kernel/locking/lockdep.c:2957 [inline]
 check_deadlock kernel/locking/lockdep.c:3000 [inline]
 validate_chain+0x485d/0x65c0 kernel/locking/lockdep.c:3785
 __lock_acquire+0x129a/0x1f80 kernel/locking/lockdep.c:5022
 lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5634
 lock_sock_nested+0x44/0xf0 net/core/sock.c:3312
 lock_sock include/net/sock.h:1682 [inline]
 rfcomm_sk_state_change+0x52/0x2f0 net/bluetooth/rfcomm/sock.c:73
 __rfcomm_dlc_close+0x2bb/0x470 net/bluetooth/rfcomm/core.c:489
 rfcomm_dlc_close+0x10d/0x1c0 net/bluetooth/rfcomm/core.c:520
 __rfcomm_sock_close+0x101/0x220 net/bluetooth/rfcomm/sock.c:220
 rfcomm_sock_shutdown+0xa5/0x220 net/bluetooth/rfcomm/sock.c:905
 rfcomm_sock_release+0x55/0x120 net/bluetooth/rfcomm/sock.c:925
 __sock_release net/socket.c:650 [inline]
 sock_close+0xd7/0x260 net/socket.c:1318
 __fput+0x3b9/0x820 fs/file_table.c:317
 task_work_run+0x146/0x1c0 kernel/task_work.c:177
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x547/0x1eb0 kernel/exit.c:795
 do_group_exit+0x23b/0x2f0 kernel/exit.c:925
 get_signal+0x172f/0x1780 kernel/signal.c:2875
 arch_do_signal_or_restart+0x8d/0x750 arch/x86/kernel/signal.c:869
 exit_to_user_mode_loop+0x74/0x160 kernel/entry/common.c:166
 exit_to_user_mode_prepare+0xad/0x110 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x2e/0x60 kernel/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f81bfac71a9
Code: Unable to access opcode bytes at RIP 0x7f81bfac717f.
RSP: 002b:00007ffe73b98968 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: fffffffffffffffc RBX: 0000000000000003 RCX: 00007f81bfac71a9
RDX: 0000000000000080 RSI: 00000000200001c0 RDI: 0000000000000004
RBP: 0000000000000003 R08: 000000ff00000001 R09: 000000ff00000001
R10: 0000000000000000 R11: 0000000000000246 R12: 000055555675d2b8
R13: 0000000000000072 R14: 00007ffe73b989c0 R15: 0000000000000003
 </TASK>