BFS-fs: bfs_fill_super(): loop3 is unclean, continuing
============================================
WARNING: possible recursive locking detected
4.14.302-syzkaller #0 Not tainted
--------------------------------------------
syz-executor.2/9814 is trying to acquire lock:
 (&port_lock_key){-.-.}, at: [<ffffffff835aeeb9>] uart_write+0x109/0x560 drivers/tty/serial/serial_core.c:611

but task is already holding lock:
 (&port_lock_key){-.-.}, at: [<ffffffff835ca350>] serial8250_handle_irq.part.0+0x20/0x390 drivers/tty/serial/8250/8250_port.c:1894

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.2/9814:
 #0:  (&(&i->lock)->rlock){-.-.}, at: [<ffffffff835b76da>] spin_lock include/linux/spinlock.h:317 [inline]
 #0:  (&(&i->lock)->rlock){-.-.}, at: [<ffffffff835b76da>] serial8250_interrupt+0x3a/0x210 drivers/tty/serial/8250/8250_core.c:119
 #1:  (&port_lock_key){-.-.}, at: [<ffffffff835ca350>] serial8250_handle_irq.part.0+0x20/0x390 drivers/tty/serial/8250/8250_port.c:1894
 #2:  (&tty->ldisc_sem){++++}, at: [<ffffffff8355c8db>] tty_ldisc_ref+0x1b/0x80 drivers/tty/tty_ldisc.c:305

stack backtrace:
CPU: 1 PID: 9814 Comm: syz-executor.2 Not tainted 4.14.302-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 print_deadlock_bug kernel/locking/lockdep.c:1800 [inline]
 check_deadlock kernel/locking/lockdep.c:1847 [inline]
 validate_chain kernel/locking/lockdep.c:2448 [inline]
 __lock_acquire.cold+0x180/0x97c kernel/locking/lockdep.c:3491
 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x8c/0xc0 kernel/locking/spinlock.c:160
 uart_write+0x109/0x560 drivers/tty/serial/serial_core.c:611
 n_hdlc_send_frames+0x241/0x410 drivers/tty/n_hdlc.c:404
 n_hdlc_tty_wakeup+0x95/0xb0 drivers/tty/n_hdlc.c:480
 tty_wakeup+0xc3/0xf0 drivers/tty/tty_io.c:533
 tty_port_default_wakeup+0x26/0x40 drivers/tty/tty_port.c:49
 serial8250_tx_chars+0x3fe/0xc70 drivers/tty/serial/8250/8250_port.c:1828
 serial8250_handle_irq.part.0+0x2c7/0x390 drivers/tty/serial/8250/8250_port.c:1918
 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1891 [inline]
 serial8250_default_handle_irq+0x8a/0x1f0 drivers/tty/serial/8250/8250_port.c:1934
 serial8250_interrupt+0xf3/0x210 drivers/tty/serial/8250/8250_core.c:129
 __handle_irq_event_percpu+0xee/0x7f0 kernel/irq/handle.c:147
 handle_irq_event_percpu kernel/irq/handle.c:187 [inline]
 handle_irq_event+0xed/0x240 kernel/irq/handle.c:204
 handle_edge_irq+0x224/0xc40 kernel/irq/chip.c:770
 generic_handle_irq_desc include/linux/irqdesc.h:159 [inline]
 handle_irq+0x35/0x50 arch/x86/kernel/irq_64.c:87
 do_IRQ+0x93/0x1d0 arch/x86/kernel/irq.c:230
 common_interrupt+0x93/0x93 arch/x86/entry/entry_64.S:578
 </IRQ>
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x50/0x80 kernel/locking/spinlock.c:200
RSP: 0018:ffff8880af207638 EFLAGS: 00000282 ORIG_RAX: ffffffffffffffc8
RAX: 1ffffffff11e13db RBX: ffff888092c16100 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff888092c16984
RBP: ffff8880ba534400 R08: ffffffff8b9c8a88 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880ba534400
R13: ffff8880937024c0 R14: 0000000000000000 R15: ffff8880ba534d50
 finish_lock_switch kernel/sched/sched.h:1346 [inline]
 finish_task_switch+0x178/0x610 kernel/sched/core.c:2678
 context_switch kernel/sched/core.c:2814 [inline]
 __schedule+0x893/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 schedule_timeout+0x80a/0xe90 kernel/time/timer.c:1724
 unix_wait_for_peer+0x1da/0x210 net/unix/af_unix.c:1244
 unix_dgram_sendmsg+0xeab/0x1080 net/unix/af_unix.c:1815
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 ___sys_sendmsg+0x326/0x800 net/socket.c:2062
 __sys_sendmmsg+0x129/0x330 net/socket.c:2152
 SYSC_sendmmsg net/socket.c:2183 [inline]
 SyS_sendmmsg+0x2f/0x50 net/socket.c:2178
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x5e/0xd3
RIP: 0033:0x7f1c5501a0c9
RSP: 002b:00007f1c5358c168 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f1c55139f80 RCX: 00007f1c5501a0c9
RDX: 0000000000000318 RSI: 00000000200bd000 RDI: 0000000000000006
RBP: 00007f1c55075ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd960bb3df R14: 00007f1c5358c300 R15: 0000000000022000
watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [syz-executor.2:9821]
Modules linked in:
irq event stamp: 301495
hardirqs last  enabled at (301495): [<ffffffff8724cbb9>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
hardirqs last  enabled at (301495): [<ffffffff8724cbb9>] _raw_spin_unlock_irqrestore+0x79/0xe0 kernel/locking/spinlock.c:192
hardirqs last disabled at (301494): [<ffffffff8724c846>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
hardirqs last disabled at (301494): [<ffffffff8724c846>] _raw_spin_lock_irqsave+0x66/0xc0 kernel/locking/spinlock.c:160
softirqs last  enabled at (298602): [<ffffffff8760068b>] __do_softirq+0x68b/0x9ff kernel/softirq.c:314
softirqs last disabled at (298591): [<ffffffff81322d13>] invoke_softirq kernel/softirq.c:368 [inline]
softirqs last disabled at (298591): [<ffffffff81322d13>] irq_exit+0x193/0x240 kernel/softirq.c:409
CPU: 0 PID: 9821 Comm: syz-executor.2 Not tainted 4.14.302-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
task: ffff8880b32ee3c0 task.stack: ffff8880b3b18000
RIP: 0010:__read_once_size include/linux/compiler.h:185 [inline]
RIP: 0010:csd_lock_wait kernel/smp.c:108 [inline]
RIP: 0010:smp_call_function_single+0x181/0x370 kernel/smp.c:302
RSP: 0018:ffff8880b3b1f480 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff10
RAX: 0000000000040000 RBX: 1ffff11016763e94 RCX: ffffc90008ef9000
RDX: 0000000000040000 RSI: ffffffff814c8bcf RDI: 0000000000000282
RBP: ffff8880b3b1f540 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: ffff8880b32ee3c0 R12: 0000000000000000
R13: ffff8880b3b1f5f8 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f1c5356b700(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020400030 CR3: 00000000a02ca000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 smp_call_function_many+0x60f/0x7a0 kernel/smp.c:434
 flush_tlb_others arch/x86/include/asm/paravirt.h:309 [inline]
 flush_tlb_mm_range+0x158/0x2f0 arch/x86/mm/tlb.c:709
 pmdp_huge_clear_flush+0x15f/0x250 mm/pgtable-generic.c:131
 do_huge_pmd_wp_page+0xc72/0x4730 mm/huge_memory.c:1344
 wp_huge_pmd mm/memory.c:4011 [inline]
 __handle_mm_fault+0x20b2/0x4620 mm/memory.c:4224
 handle_mm_fault+0x455/0x9c0 mm/memory.c:4271
 __do_page_fault+0x549/0xad0 arch/x86/mm/fault.c:1442
 page_fault+0x25/0x50 arch/x86/entry/entry_64.S:1126
RIP: 0010:___sys_recvmsg+0x2b8/0x4d0 net/socket.c:2233
RSP: 0018:ffff8880b3b1fad8 EFLAGS: 00050246
RAX: 0000000000000000 RBX: ffff8880b3b1fdd0 RCX: ffffc90008ef9000
RDX: 0000000000040000 RSI: ffffffff85bd2556 RDI: 0000000000000282
RBP: 0000000000000000 R08: ffff8880b32ee3c0 R09: dffffc0000000000
R10: 0000000000000000 R11: ffff8880b32ee3c0 R12: 0000000000000000
R13: 0000000020400000 R14: 0000000020400030 R15: 0000000000000002
 __sys_recvmmsg+0x1f3/0x5d0 net/socket.c:2329
 SYSC_recvmmsg net/socket.c:2405 [inline]
 SyS_recvmmsg+0x125/0x140 net/socket.c:2394
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x5e/0xd3
RIP: 0033:0x7f1c5501a0c9
RSP: 002b:00007f1c5356b168 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f1c5513a050 RCX: 00007f1c5501a0c9
RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000005
RBP: 00007f1c55075ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd960bb3df R14: 00007f1c5356b300 R15: 0000000000022000
Code: ce 08 00 48 8b 54 24 10 4c 89 e9 8b 7c 24 1c 48 8d 74 24 40 e8 71 fa ff ff 41 89 c4 8b 44 24 58 a8 01 74 0f e8 71 ce 08 00 f3 90 <8b> 44 24 58 a8 01 75 f1 e8 62 ce 08 00 e8 5d ce 08 00 bf 01 00 
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff8724bc3d
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	08 00                	or     %al,(%rax)
   2:	48 8b 54 24 10       	mov    0x10(%rsp),%rdx
   7:	4c 89 e9             	mov    %r13,%rcx
   a:	8b 7c 24 1c          	mov    0x1c(%rsp),%edi
   e:	48 8d 74 24 40       	lea    0x40(%rsp),%rsi
  13:	e8 71 fa ff ff       	callq  0xfffffa89
  18:	41 89 c4             	mov    %eax,%r12d
  1b:	8b 44 24 58          	mov    0x58(%rsp),%eax
  1f:	a8 01                	test   $0x1,%al
  21:	74 0f                	je     0x32
  23:	e8 71 ce 08 00       	callq  0x8ce99
  28:	f3 90                	pause
* 2a:	8b 44 24 58          	mov    0x58(%rsp),%eax <-- trapping instruction
  2e:	a8 01                	test   $0x1,%al
  30:	75 f1                	jne    0x23
  32:	e8 62 ce 08 00       	callq  0x8ce99
  37:	e8 5d ce 08 00       	callq  0x8ce99
  3c:	bf                   	.byte 0xbf
  3d:	01 00                	add    %eax,(%rax)