INFO: task syz.0.2578:2037 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.2578      state:D stack:25128 pid:2037  tgid:2036  ppid:32385  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_write_slowpath+0x872/0xfe0
 down_write+0x1ab/0x1f0
 super_lock+0x25c/0x3b0
 user_get_super+0xc8/0x120
 __se_sys_quotactl+0x4da/0x950
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fddab38ec29
RSP: 002b:00007fddac19e038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007fddab5d5fa0 RCX: 00007fddab38ec29
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: ffffffff80000200
RBP: 00007fddab411e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000040 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fddab5d6038 R14: 00007fddab5d5fa0 R15: 00007ffc684b3b18
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e33d320 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
3 locks held by kworker/u9:9/1183:
 #0: ffff88801ac89948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900075dfba0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f73f388 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60
1 lock held by dhcpcd/5593:
 #0: ffffffff8f73f388 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0
2 locks held by getty/5672:
 #0: ffff888108ff30a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900028fe2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
5 locks held by kworker/u8:3/13479:
 #0: ffff88801baff148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900030c7ba0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f732250 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x820
 #3: ffffffff8f73f388 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xdc/0x890
 #4: ffffffff8e342db8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730
3 locks held by syz-executor/29157:
1 lock held by syz.0.2578/2037:
 #0: ffff88811140c0e0 (&type->s_umount_key#64){++++}-{4:4}, at: super_lock+0x25c/0x3b0
2 locks held by syz-executor/2118:
 #0: ffff88810f9940e0 (&type->s_umount_key#66){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
 #1: ffffffff8e779128 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520
2 locks held by syz-executor/3341:
 #0: ffff88810d4240e0 (&type->s_umount_key#66){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
 #1: ffffffff8e779128 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520
1 lock held by syz-executor/4344:
 #0: ffffffff8f73f388 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8e9/0x1c80
4 locks held by syz.5.2723/4394:

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

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+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf60/0xfa0
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 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: 13479 Comm: kworker/u8:3 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:zap_class+0xc2/0x360
Code: 49 81 fc 00 00 08 00 0f 84 a5 01 00 00 4e 8b 2c e5 60 03 86 93 4d 85 ed 0f 94 c0 49 83 c5 f8 0f 94 c1 08 c1 75 d7 45 8b 7d 00 <41> f6 c7 fc 0f 84 e2 00 00 00 41 c1 ef 08 4e 8d 34 7d 30 03 cb 92
RSP: 0018:ffffc900030c7518 EFLAGS: 00000046
RAX: 000000000005bc00 RBX: 0000000000000ece RCX: 000000000005bc00
RDX: ffffffff93860358 RSI: 0000000000000005 RDI: 00000000000b721c
RBP: ffffffff93ca07d0 R08: 0000000000000000 R09: ffffffff81ab1bd8
R10: dffffc0000000000 R11: fffffbfff1f86aef R12: 000000000004e352
R13: ffffffff93f7ff70 R14: ffffffff92d67c3a R15: 0000000008865b10
FS:  0000000000000000(0000) GS:ffff8881a39fc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2e901f CR3: 0000000106bf8000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lockdep_unregister_key+0x1a6/0x310
 __qdisc_destroy+0x167/0x430
 dev_shutdown+0x93/0x440
 unregister_netdevice_many_notify+0xe0f/0x1ff0
 default_device_exit_batch+0x819/0x890
 ops_undo_list+0x525/0x990
 cleanup_net+0x4d8/0x820
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 ret_from_fork_asm+0x1a/0x30
 </TASK>
