F2FS-fs (loop3): Found nat_bits in checkpoint
netlink: 12 bytes leftover after parsing attributes in process `syz-executor.1'.
F2FS-fs (loop4): Found nat_bits in checkpoint
bond1: refused to change device type
============================================
WARNING: possible recursive locking detected
4.19.211-syzkaller #0 Not tainted
--------------------------------------------
syz-executor.1/25028 is trying to acquire lock:
00000000d1669b68 (&port_lock_key){-.-.}, at: uart_write+0x1ce/0x6f0 drivers/tty/serial/serial_core.c:591

but task is already holding lock:
00000000d1669b68 (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1876

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

       CPU0
       ----
  lock(&port_lock_key);
  lock(&port_lock_key);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

3 locks held by syz-executor.1/25028:
 #0: 0000000092a487b1 (&(&i->lock)->rlock){-.-.}, at: spin_lock include/linux/spinlock.h:329 [inline]
 #0: 0000000092a487b1 (&(&i->lock)->rlock){-.-.}, at: serial8250_interrupt+0x3a/0x240 drivers/tty/serial/8250/8250_core.c:115
 #1: 00000000d1669b68 (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1876
 #2: 00000000c0f5b0bf (&tty->ldisc_sem){++++}, at: tty_ldisc_ref+0x1d/0x80 drivers/tty/tty_ldisc.c:293

stack backtrace:
CPU: 1 PID: 25028 Comm: syz-executor.1 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 print_deadlock_bug kernel/locking/lockdep.c:1764 [inline]
 check_deadlock kernel/locking/lockdep.c:1808 [inline]
 validate_chain kernel/locking/lockdep.c:2404 [inline]
 __lock_acquire.cold+0x121/0x57e kernel/locking/lockdep.c:3416
 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x8c/0xc0 kernel/locking/spinlock.c:152
 uart_write+0x1ce/0x6f0 drivers/tty/serial/serial_core.c:591
 n_hdlc_send_frames+0x278/0x470 drivers/tty/n_hdlc.c:403
 n_hdlc_tty_wakeup+0xa0/0xc0 drivers/tty/n_hdlc.c:479
 tty_wakeup+0xd4/0x110 drivers/tty/tty_io.c:534
 tty_port_default_wakeup+0x26/0x40 drivers/tty/tty_port.c:50
 serial8250_tx_chars+0x490/0xaf0 drivers/tty/serial/8250/8250_port.c:1813
 serial8250_handle_irq.part.0+0x31f/0x3d0 drivers/tty/serial/8250/8250_port.c:1900
 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1873 [inline]
 serial8250_default_handle_irq+0xae/0x220 drivers/tty/serial/8250/8250_port.c:1916
 serial8250_interrupt+0x101/0x240 drivers/tty/serial/8250/8250_core.c:125
 __handle_irq_event_percpu+0x27e/0x8e0 kernel/irq/handle.c:149
 handle_irq_event_percpu kernel/irq/handle.c:189 [inline]
 handle_irq_event+0x102/0x290 kernel/irq/handle.c:206
 handle_edge_irq+0x260/0xcf0 kernel/irq/chip.c:800
 generic_handle_irq_desc include/linux/irqdesc.h:155 [inline]
 handle_irq+0x35/0x50 arch/x86/kernel/irq_64.c:87
 do_IRQ+0x93/0x1c0 arch/x86/kernel/irq.c:246
 common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:670
 </IRQ>
RIP: 0033:0x7fae2930d7f9
Code: 31 c5 c1 e8 0f 31 c5 80 3d cc cb 0a 01 00 75 81 44 0f b6 6c 24 0f 44 8d 4d 04 89 e8 41 89 c0 41 81 e0 ff 1f 00 00 43 8b 14 84 <39> d5 0f 84 70 ff ff ff 85 d2 0f 84 67 01 00 00 83 c0 01 41 39 c1
RSP: 002b:00007fff290fc5f0 EFLAGS: 00000202 ORIG_RAX: ffffffffffffffd5
RAX: 0000000001f21176 RBX: 00007fae29481018 RCX: 0000001b2ef20000
RDX: 0000000001f21176 RSI: 0000001b2ef25188 RDI: 0000000009f1334f
RBP: 0000000001f21176 R08: 0000000000001176 R09: 0000000001f2117a
R10: 0000000000000000 R11: 0000000000000000 R12: 00007fae29475000
R13: 0000000000000001 R14: 000000000002a82c R15: ffffffff87f0ace2