INFO: task syz.2.4255:20842 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.4255      state:D stack:27688 pid:20842 tgid:20841 ppid:16360  task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x5fd/0x8f0
 down_read+0x98/0x2e0
 super_lock+0x2a9/0x3b0
 __iterate_supers+0x126/0x290
 __se_sys_quotactl+0x353/0x950
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1c1058ebe9
RSP: 002b:00007f1c1133d038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f1c107c5fa0 RCX: 00007f1c1058ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000101
RBP: 00007f1c10611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1c107c6038 R14: 00007f1c107c5fa0 R15: 00007ffd8e0ddb38
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/u8:0/12:
 #0: ffff88804b039f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140
 #1: ffff88804b024008 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880
 #2: ffff88804b025918 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x1ae/0xf30
1 lock held by khungtaskd/34:
 #0: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5673:
 #0: ffff88801c7f90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
1 lock held by sshd/5830:
2 locks held by syz-executor/8256:
2 locks held by syz-executor/10492:
2 locks held by syz-executor/11227:
4 locks held by syz-executor/12019:
3 locks held by syz-executor/12536:
7 locks held by kworker/u8:2/16373:
 #0: ffff88801b2f7148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900040cfbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f52bdb0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800
 #3: ffff8881086c70e8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x10a/0x3d0
 #4: ffff88811c98b250 (&devlink->lock_key#19){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x11c/0x3d0
 #5: ffffffff8f538c48 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0xe5/0x670
 #6: ffffffff8e13f9b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730
2 locks held by syz-executor/19128:
1 lock held by syz.2.4255/20842:
 #0: ffff888038ad80e0 (&type->s_umount_key#100){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
2 locks held by syz.3.4631/22176:
 #0: ffffffff8f52bdb0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x304/0x4d0
 #1: ffffffff8f538c48 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x2ab/0x800
1 lock held by syz-executor/22181:
 #0: ffffffff8f538c48 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0
1 lock held by syz.5.4633/22185:
 #0: ffffffff8e13f9b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730

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

NMI backtrace for cpu 1
CPU: 1 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+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf93/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 19710 Comm: kworker/0:7 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: events legacy_dvb_usb_read_remote_control
RIP: 0010:io_serial_out+0x7c/0xc0
Code: 72 70 fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 bc e0 d3 fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d e9 97 6f 2d 06 cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc9000439f330 EFLAGS: 00000002
RAX: 0000000000000031 RBX: 0000000000000031 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f8 R08: ffff88801bbe0237 R09: 1ffff1100377c046
R10: dffffc0000000000 R11: ffffffff854f3b00 R12: dffffc0000000000
R13: ffffffff99afd8c5 R14: ffffffff99df2420 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8618000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f98ee01bd58 CR3: 0000000118640000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 serial8250_console_write+0x1410/0x1ba0
 console_flush_all+0x728/0xc40
 console_unlock+0xc4/0x270
 vprintk_emit+0x5b7/0x7a0
 _printk+0xcf/0x120
 m920x_rc_query+0x2f6/0x830
 legacy_dvb_usb_read_remote_control+0x100/0x470
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
