INFO: task syz.4.323:8761 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.323       state:D stack:24856 pid:8761  tgid:8760  ppid:8489   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x153c/0x4fe0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x61e/0x920
 down_read+0x99/0x2e0
 super_lock+0x2d6/0x3d0
 __iterate_supers+0x126/0x290
 __se_sys_quotactl+0x382/0x990
 do_syscall_64+0xe2/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc87d99acb9
RSP: 002b:00007fc87e771028 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007fc87dc15fa0 RCX: 00007fc87d99acb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000101
RBP: 00007fc87da08bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc87dc16038 R14: 00007fc87dc15fa0 R15: 00007ffc5a8bf878
 </TASK>

Showing all locks held in the system:
7 locks held by kworker/u8:1/13:
 #0: ffff888100eef948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x855/0x15a0
 #1: ffffc90000127c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x87c/0x15a0
 #2: ffffffff8f70a3f0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xfe/0x7b0
 #3: ffff8881156960e8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x117/0x3f0
 #4: ffff888115693250 (&devlink->lock_key#27){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x129/0x3f0
 #5: ffffffff8f717a08 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0x10b/0x730
 #6: ffff88816e64cd48 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: unregister_netdevice_many_notify+0x118e/0x2380
1 lock held by khungtaskd/34:
 #0: ffffffff8e33f020 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5638:
 #0: ffff888175fd70a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000356e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0
2 locks held by syz-executor/7222:
1 lock held by syz.4.323/8761:
 #0: ffff88810d4de0e0 (&type->s_umount_key#53){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.8.566/11080:
 #0: ffff88810d4de0e0 (&type->s_umount_key#53){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.4.729/12467:
 #0: ffff88810d4de0e0 (&type->s_umount_key#53){++++}-{4:4}, at: super_lock+0x2d6/0x3d0

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 34 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xe83/0xed0
 kthread+0x388/0x470
 ret_from_fork+0x51b/0xa40
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 13 Comm: kworker/u8:1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: netns cleanup_net
RIP: 0010:vsnprintf+0x11c/0xee0
Code: 4c 89 ff 4c 89 f6 48 8d 54 24 48 e8 ee 0d 00 00 48 89 c5 49 89 d6 41 0f b6 fe 48 c7 c6 80 bd a9 8f e8 18 6b 4d f6 41 0f b6 c6 <83> f8 03 0f 8f bb 00 00 00 83 f8 01 0f 8f 45 01 00 00 85 c0 0f 84
RSP: 0018:ffffc90000126530 EFLAGS: 00000246
RAX: 0000000000000001 RBX: dffffc0000000000 RCX: 0000000000000001
RDX: ffffffff8b74cfb8 RSI: ffffffff8fa9bd80 RDI: 0000000000000001
RBP: ffffffff8b8bb9e4 R08: ffff888102af8000 R09: 0000000000000008
R10: 0000000000000007 R11: 0000000000000000 R12: ffffc90000126620
R13: ffffc90000126701 R14: 0000000000000401 R15: ffffffff8b8bb9e2
FS:  0000000000000000(0000) GS:ffff8882a99f4000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000003e000 CR3: 00000001ac2e3000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 snprintf+0xe8/0x140
 info_print_prefix+0x1fd/0x360
 record_print_text+0x176/0x450
 printk_get_next_message+0x29c/0x880
 console_flush_all+0x501/0xb20
 console_unlock+0xd1/0x1c0
 vprintk_emit+0x485/0x560
 dev_vprintk_emit+0x355/0x420
 dev_printk_emit+0xee/0x140
 __netdev_printk+0x3e1/0x480
 netdev_info+0x11e/0x180
 nsim_udp_tunnel_unset_port+0x2d0/0x530
 __udp_tunnel_nic_device_sync+0xb9f/0x1580
 udp_tunnel_nic_flush+0x2cc/0x670
 udp_tunnel_nic_netdevice_event+0xfbf/0x17e0
 notifier_call_chain+0x19d/0x3a0
 unregister_netdevice_many_notify+0x186a/0x2380
 unregister_netdevice_queue+0x31f/0x360
 nsim_destroy+0x21f/0x730
 __nsim_dev_port_del+0x14d/0x1b0
 nsim_dev_reload_destroy+0x288/0x490
 nsim_dev_reload_down+0x8a/0xc0
 devlink_reload+0x1d1/0x8e0
 devlink_pernet_pre_exit+0x1e6/0x3f0
 ops_undo_list+0x187/0x940
 cleanup_net+0x4df/0x7b0
 process_one_work+0x949/0x15a0
 worker_thread+0x9af/0xee0
 kthread+0x388/0x470
 ret_from_fork+0x51b/0xa40
 ret_from_fork_asm+0x1a/0x30
 </TASK>
