INFO: task kworker/u8:4:5859 blocked for more than 144 seconds.
      Not tainted 6.16.0-rc6-syzkaller-00135-gcf074eca0065-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:4    state:D stack:22648 pid:5859  tgid:5859  ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
 <TASK>
 __schedule+0x16f5/0x4d00
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x724/0xe80
 addrconf_dad_work+0x112/0x14b0
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/0:0/9:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900000c7bc0 (reg_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f51bc48 (rtnl_mutex){+.+.}-{4:4}, at: reg_todo+0x1c/0x890
5 locks held by kworker/0:1/10:
1 lock held by khungtaskd/34:
 #0: ffffffff8e13f0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
5 locks held by kworker/u10:1/36:
2 locks held by kswapd0/84:
2 locks held by kswapd1/91:
2 locks held by kworker/0:2/974:
5 locks held by kworker/u9:6/1091:
3 locks held by kworker/u9:8/1098:
1 lock held by klogd/5266:
5 locks held by udevd/5277:
3 locks held by dhcpcd/5573:
2 locks held by getty/5655:
 #0: ffff888107c390a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029132f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
1 lock held by syz-executor/5828:
 #0: ffffffff8f51bc48 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
1 lock held by syz-executor/5832:
 #0: ffffffff8f51bc48 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
3 locks held by kworker/u8:4/5859:
 #0: ffff888027d39148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000360fbc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f51bc48 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0
3 locks held by syz.1.203/6498:
3 locks held by kworker/0:8/6507:
 #0: ffff88801a481d48 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90008277bc0 ((reg_check_chans).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f51bc48 (rtnl_mutex){+.+.}-{4:4}, at: reg_check_chans_work+0x95/0xf00
2 locks held by syz-executor/6509:
3 locks held by syz-executor/6511:
3 locks held by syz-executor/6514:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 34 Comm: khungtaskd Not tainted 6.16.0-rc6-syzkaller-00135-gcf074eca0065-dirty #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+0xfee/0x1030
 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: 5875 Comm: napi/wg1-0 Not tainted 6.16.0-rc6-syzkaller-00135-gcf074eca0065-dirty #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:unwind_next_frame+0x4d7/0x2390
Code: 00 00 41 c6 07 01 48 c7 c2 e0 46 88 8b 4c 8b 6c 24 50 48 8d 72 04 4c 8d 62 05 48 89 f0 48 c1 e8 03 48 89 44 24 40 0f b6 04 28 <84> c0 48 89 54 24 08 48 89 34 24 0f 85 4d 18 00 00 4c 89 e0 48 c1
RSP: 0018:ffffc90000006c58 EFLAGS: 00000a02
RAX: 0000000000000000 RBX: ffffffff900ee888 RCX: ffffffff900ee88c
RDX: ffffffff90b74f24 RSI: ffffffff90b74f28 RDI: ffffffff8be28ba0
RBP: dffffc0000000000 R08: 0000000000000007 R09: ffffffff8172aae5
R10: ffffc90000006d78 R11: ffffffff81ad0050 R12: ffffffff90b74f29
R13: ffffc90000006d78 R14: ffffc90000006d28 R15: ffffffff8172aae5
FS:  0000000000000000(0000) GS:ffff8880b8623000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f962bbb2060 CR3: 000000010a580000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_track+0x3e/0x80
 __kasan_slab_alloc+0x6c/0x80
 kmem_cache_alloc_noprof+0x1c1/0x3c0
 skb_clone+0x212/0x3a0
 br_flood+0x414/0x6a0
 br_handle_frame_finish+0x14b4/0x19b0
 br_nf_pre_routing_finish+0x1312/0x1a90
 NF_HOOK+0x61b/0x6b0
 br_nf_pre_routing+0xeb7/0x1470
 br_handle_frame+0x982/0x14c0
 __netif_receive_skb_core+0x10e1/0x4180
 __netif_receive_skb+0x72/0x380
 process_backlog+0x60e/0x14f0
 __napi_poll+0xc7/0x480
 net_rx_action+0x707/0xe30
 handle_softirqs+0x286/0x870
 do_softirq+0xec/0x180
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x17d/0x1c0
 napi_threaded_poll_loop+0x50e/0x6c0
 napi_threaded_poll+0x1be/0x2b0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
