INFO: task kworker/u8:3:5658 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:3    state:D stack:23584 pid:5658  tgid:5658  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: ipv6_addrconf addrconf_verify_work
Call Trace:
 <TASK>
 __schedule+0x17d9/0x56c0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7bf/0x1550
 addrconf_verify_work+0x19/0x30
 process_scheduled_works+0xa8e/0x14e0
 worker_thread+0xa47/0xfb0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
1 lock held by dhcpcd/5347:
 #0: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0
2 locks held by getty/5436:
 #0: ffff88816ec670a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034732e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
4 locks held by kworker/u8:2/5637:
 #0: ffff8881012d5940 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc90004defc40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #2: ffffffff90018348 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf5/0x810
 #3: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: ip_mc_drop_socket+0x80/0x280
3 locks held by kworker/u8:3/5658:
 #0: ffff88810ff7d140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc90004f2fc40 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #2: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x19/0x30
3 locks held by kworker/u10:4/16000:
 #0: ffff8881000ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc900036d7c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #2: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60
3 locks held by kworker/0:6/16247:
 #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc9000746fc40 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #2: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20
1 lock held by syz.6.6030/30032:
1 lock held by syz-executor/30309:
 #0: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
1 lock held by syz-executor/30317:
 #0: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
1 lock held by syz-executor/30323:
 #0: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
2 locks held by syz-executor/30378:
 #0: ffffffff90018348 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4e2/0x720
 #1: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: register_nexthop_notifier+0x8b/0x290
1 lock held by syz-executor/30386:
 #0: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0
3 locks held by kworker/u8:6/30390:
1 lock held by syz-executor/30392:
 #0: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x464/0x19e0
1 lock held by syz-executor/30423:
 #0: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x464/0x19e0
1 lock held by syz-executor/30431:
 #0: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x464/0x19e0
1 lock held by syz-executor/30436:
 #0: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x464/0x19e0
1 lock held by syz-executor/30443:
 #0: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x464/0x19e0
1 lock held by syz-executor/30450:
 #0: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x464/0x19e0
1 lock held by syz-executor/30459:
 #0: ffffffff90026f00 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x464/0x19e0

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

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/0x380
 sys_info+0x135/0x170
 watchdog+0xfd7/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 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: 30390 Comm: kworker/u8:6 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: bat_events batadv_tt_purge
RIP: 0010:irqentry_exit+0x213/0x8f0
Code: 88 04 00 74 1a 65 8b 0d 7b 56 9d 07 85 c9 75 0f 65 8b 0d 08 52 9d 07 85 c9 0f 85 91 06 00 00 a9 00 10 00 00 0f 85 95 06 00 00 <e8> b8 2e 00 f6 90 e9 f1 fe ff ff 89 f8 25 30 10 00 00 3d 00 10 00
RSP: 0018:ffffc90000a08e40 EFLAGS: 00000082
RAX: 0000000080000102 RBX: 0000000000000000 RCX: 0000000000000100
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 00000000ffffffff
RBP: 0000000000000000 R08: ffff88823c6281c3 R09: 1ffff110478c5038
R10: dffffc0000000000 R11: ffffed10478c5039 R12: 0000000000000000
R13: 0000000000000000 R14: ffffc90000a08e98 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8882a8f5e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f693c66f9d1 CR3: 000000011382c000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80
Code: f7 e8 2d 9d d1 f5 f7 c3 00 02 00 00 74 05 e8 00 7e fd f5 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> c4 b0 c2 f5 65 8b 05 bd 60 9a 07 85 c0 74 18 5b 41 5e c3 cc cc
RSP: 0018:ffffc90000a08f40 EFLAGS: 00000206
RAX: 0000000000000006 RBX: 0000000000000246 RCX: 0000000080000102
RDX: 0000000000000002 RSI: ffffffff8e227366 RDI: 0000000000000001
RBP: ffffffff8e80a100 R08: ffffffff90572e37 R09: 1ffffffff20ae5c6
R10: dffffc0000000000 R11: fffffbfff20ae5c7 R12: 0000000000000009
R13: 0000000000000008 R14: ffff88823c6281c0 R15: 0000000000000001
 handle_softirqs+0x225/0x840
 do_softirq+0x76/0xd0
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x130
 batadv_tt_purge+0x4ae/0xa10
 process_scheduled_works+0xa8e/0x14e0
 worker_thread+0xa47/0xfb0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
