INFO: task syz.2.10:5962 blocked for more than 155 seconds.
      Not tainted syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.10        state:D stack:27416 pid:5962  tgid:5962  ppid:5848   task_flags:0x40004c flags:0x00004002
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_timeout+0x9a/0x270
 __down_common+0x319/0x6a0
 down+0x80/0xd0
 console_lock+0x145/0x1b0
 con_shutdown+0x48/0x80
 release_tty+0xcc/0x570
 tty_release_struct+0xb8/0xd0
 tty_release+0xcb0/0x1640
 __fput+0x44c/0xa70
 task_work_run+0x1d4/0x260
 do_exit+0x6b5/0x2300
 __x64_sys_exit+0x40/0x40
 x64_sys_call+0x21da/0x2200
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa510d8ebe9
RSP: 002b:00007fa511b4bfe8 EFLAGS: 00000246 ORIG_RAX: 000000000000003c
RAX: ffffffffffffffda RBX: 00007fa510fc6090 RCX: 00007fa510d8ebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fa510e11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa510fc6128 R14: 00007fa510fc6090 R15: 00007ffeabe1fc88
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/u8:1/13:
3 locks held by kworker/u10:0/27:
6 locks held by kworker/u9:1/32:
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/u10:1/36:
3 locks held by kworker/u9:2/52:
3 locks held by kworker/u9:3/88:
2 locks held by kworker/1:2/856:
3 locks held by kworker/u10:6/1095:
4 locks held by kworker/0:3/1895:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90009b87bc0 (reg_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f5388c8 (rtnl_mutex){+.+.}-{4:4}, at: reg_todo+0x1c/0x890
 #3: ffff88810f8f8768 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: reg_process_self_managed_hints+0xaf/0x1c0
3 locks held by kworker/u9:4/4257:
3 locks held by kworker/u9:5/4679:
3 locks held by syslogd/5281:
4 locks held by udevd/5299:
2 locks held by dhcpcd/5594:
2 locks held by getty/5677:
 #0: ffff888020cc50a0 (&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 syz-executor/5775:
1 lock held by syz-executor/5842:
7 locks held by kworker/u11:2/5844:
3 locks held by syz-executor/5850:
 #0: ffff8880293dcdc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x510
 #1: ffff8880293dc0b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x66a/0x1330
 #2: ffffffff8f69d588 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x230
3 locks held by kworker/u8:2/5855:
 #0: ffff8880225ae948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000361fbc0 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f5388c8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x19/0x30
6 locks held by kworker/0:4/5883:
3 locks held by kworker/1:4/5911:
 #0: ffff88801a482148 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90003a3fbc0 ((reg_check_chans).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f5388c8 (rtnl_mutex){+.+.}-{4:4}, at: reg_check_chans_work+0x95/0xf30
1 lock held by syz.2.10/5962:
 #0: ffffffff8e99d868 (tty_mutex){+.+.}-{4:4}, at: tty_release_struct+0xae/0xd0
6 locks held by syz.2.13/5966:
3 locks held by kworker/0:6/5971:
 #0: ffff88801a482148 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900047cfbc0 ((crda_timeout).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f5388c8 (rtnl_mutex){+.+.}-{4:4}, at: crda_timeout_work+0x15/0x50
2 locks held by syz-executor/5976:
3 locks held by kworker/u9:8/5977:

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

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: 5883 Comm: kworker/0:4 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_power_efficient neigh_periodic_work
RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x70
Code: 00 00 00 48 8b 3d 64 59 fe 0b 48 89 de 5b e9 43 9d 58 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa <48> 8b 04 24 65 48 8b 0c 25 08 50 a0 92 65 8b 15 88 a4 e0 10 81 e2
RSP: 0018:ffffc90000007560 EFLAGS: 00000282
RAX: ffffffff8a5c3949 RBX: ffff8880705d5680 RCX: 0000000000000100
RDX: ffff888020fe0000 RSI: 0000000000000000 RDI: ffff8880705d5680
RBP: 0000000000000000 R08: ffff8880705d56bf R09: 0000000000000000
R10: ffff8880705d56a8 R11: ffffed100e0baad8 R12: 0000000000000000
R13: ffff8880705d5680 R14: 1ffff92000000ef0 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b861b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055557574d350 CR3: 0000000023f5c000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 skb_ext_add+0x26/0x8f0
 br_nf_pre_routing_ipv6+0x132/0x6b0
 br_handle_frame+0x982/0x14c0
 __netif_receive_skb_core+0x10b9/0x4020
 __netif_receive_skb+0x72/0x380
 process_backlog+0x60e/0x14f0
 __napi_poll+0xc7/0x360
 net_rx_action+0x707/0xe30
 handle_softirqs+0x286/0x870
 do_softirq+0xec/0x180
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x17d/0x1c0
 neigh_periodic_work+0xc28/0xe50
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
