INFO: task poweroff:21663 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:poweroff        state:D stack:24088 pid:21663 tgid:21663 ppid:5282   task_flags:0x400000 flags:0x00004002
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
 ksys_sync+0x94/0x150
 __ia32_sys_sync+0xe/0x20
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f00360937e7
RSP: 002b:00007ffc0e99ca98 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f00360937e7
RDX: 0000000000000078 RSI: 00007f00362228ca RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000000000000001 R09: 00007f00362228ca
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc0e99cbe8
R13: 00007ffc0e99cbf8 R14: 000055ae248ea169 R15: 00007f0036273a80
 </TASK>

Showing all locks held in the system:
6 locks held by kworker/1:0/24:
 #0: ffff88801b705948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900001c7bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff888023447198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20
 #3: ffff88810a4d2518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x21b8/0x4a20
 #4: ffff888109b41168 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21e5/0x4a20
 #5: ffffffff8ede0950 (ehci_cf_port_reset_rwsem){.+.+}-{4:4}, at: hub_port_reset+0x163/0x1750
1 lock held by khungtaskd/34:
 #0: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
3 locks held by kworker/1:2/2207:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000a717bc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff888122562240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x26b/0x3180
2 locks held by getty/5679:
 #0: ffff888109cc70a0 (&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
5 locks held by syz-executor/5852:
6 locks held by kworker/1:5/6660:
 #0: ffff88801b705948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90002abfbc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff88810a37f198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20
 #3: ffff888112127198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400
 #4: ffff888112125160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400
 #5: ffffffff8dfe0350 (umhelper_sem){++++}-{4:4}, at: usermodehelper_read_trylock+0xf0/0x2b0
6 locks held by kworker/u8:0/19257:
 #0: ffff88801b2f7148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90002d8fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f52bdb0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800
 #3: ffffffff8f538c48 (rtnl_mutex){+.+.}-{4:4}, at: caif_exit_net+0x6a/0x4a0
 #4: ffff8881095ed080 (&caifn->caifdevs.lock){+.+.}-{4:4}, at: caif_exit_net+0x7d/0x4a0
 #5: ffffffff8e13f9b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730
3 locks held by kworker/u8:4/20819:
 #0: ffff88810f42b148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000437fbc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f538c48 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0
1 lock held by poweroff/21663:
 #0: ffff888035d620e0 (&type->s_umount_key#52){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
2 locks held by kworker/u9:25/23261:
 #0: ffff88801f378948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90003aefbc0 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
1 lock held by syz-executor/23722:
 #0: ffffffff8f538c48 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0
2 locks held by rm/23882:

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

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+0xf93/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 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: 18986 Comm: kworker/u10:25 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_unbound linkwatch_event
RIP: 0010:move_right+0x0/0xa0
Code: ac f6 e9 79 ff ff ff e8 1e 35 49 f6 48 01 eb 48 83 c3 04 e9 9d fd ff ff 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <55> 41 57 41 56 41 54 53 41 89 ce 89 d5 49 89 f7 48 89 fb e8 e8 34
RSP: 0018:ffffc900035aebc8 EFLAGS: 00000292
RAX: 0000000000000003 RBX: ffffc900035aeef2 RCX: 0000000000000003
RDX: 0000000000000003 RSI: ffffc900835aeeed RDI: ffffc900035aeeef
RBP: 00000000fffffffd R08: ffff88810a8ad640 R09: 0000000000000008
R10: 0000000000000007 R11: 0000000000000000 R12: 0000000000000003
R13: 0000000000000000 R14: ffffc900835aeeed R15: 0000000000000003
FS:  0000000000000000(0000) GS:ffff8881a3c18000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f60e8f1c3b0 CR3: 000000002968c000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 widen_string+0x85/0x2a0
 vsnprintf+0x739/0xf00
 sprintf+0xd9/0x120
 info_print_prefix+0x1f3/0x310
 record_print_text+0x154/0x420
 printk_get_next_message+0x26d/0x7b0
 console_flush_all+0x4ca/0xc40
 console_unlock+0xc4/0x270
 vprintk_emit+0x5b7/0x7a0
 _printk+0xcf/0x120
 br_set_state+0x475/0x710
 br_stp_enable_port+0x9a/0x250
 br_port_carrier_check+0x301/0x3f0
 br_device_event+0x5fa/0x910
 notifier_call_chain+0x1b6/0x3e0
 netif_state_change+0x284/0x3a0
 linkwatch_do_dev+0x117/0x170
 __linkwatch_run_queue+0x56a/0x7e0
 linkwatch_event+0x4c/0x60
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
