INFO: task kworker/0:2:63 blocked for more than 148 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:2     state:D
 stack:20072 pid:63    tgid:63    ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: events_power_efficient reg_check_chans_work
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 reg_check_chans_work+0x164/0xf30
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x47f/0x820
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
 #0: ffffffff8e342838 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730
3 locks held by kworker/1:0/24:
 #0: ffff88801a875548 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900001c7ba0 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f73f808 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20
1 lock held by khungtaskd/34:
 #0: ffffffff8e33cda0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
6 locks held by kworker/1:1/47:
2 locks held by kswapd0/86:
3 locks held by kswapd1/87:
1 lock held by klogd/5284:
3 locks held by dhcpcd/5590:
1 lock held by dhcpcd/5591:
2 locks held by getty/5674:
 #0: ffff888026f9c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000291b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
2 locks held by syz-executor/5831:
 #0: ffff88804b039f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140
 #1: ffff88804b024008 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880
2 locks held by syz-executor/5845:
 #0: ffffffff8f73f808 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
 #1: ffffffff8e342838 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730
1 lock held by syz-executor/6723:
 #0: ffffffff8f73f808 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
1 lock held by syz.2.337/6797:
 #0: ffffffff8f73f808 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
3 locks held by kworker/1:5/7724:
4 locks held by syz-executor/7725:
2 locks held by syz-executor/7732:
3 locks held by syz-executor/7733:

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

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+0x47f/0x820
 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: 47 Comm: kworker/1:1 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:check_preemption_disabled+0x40/0x120
Code: 08 65 8b 05 d6 a4 43 07 65 8b 0d cb a4 43 07 f7 c1 ff ff ff 7f 74 23 65 48 8b 0d ab a4 43 07 48 3b 4c 24 08 0f 85 cc 00 00 00 <48> 83 c4 10 5b 41 5e 41 5f 5d e9 51 c9 02 00 cc 48 c7 04 24 00 00
RSP: 0018:ffffc900001dfa80 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffffffff90dba001 RCX: 93f292b1f942a100
RDX: ffffc900001dfb01 RSI: ffffffff8c0370e0 RDI: ffffffff8c0370a0
RBP: dffffc0000000000 R08: ffffc900001e0a88 R09: 0000000000000000
R10: ffffc900001dfbf8 R11: fffff5200003bf81 R12: ffffc900001e0a98
R13: ffffc900001d9000 R14: ffffc900001dfba8 R15: ffffffff8173bd85
FS:  0000000000000000(0000) GS:ffff8881a39fa000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000557b933e4078 CR3: 000000000e138000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 rcu_is_watching+0x15/0xb0
 unwind_next_frame+0x1965/0x2390
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_track+0x3e/0x80
 __kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5b/0x80
 kmem_cache_free+0x19a/0x690
 netlink_broadcast_filtered+0xec7/0x1000
 nlmsg_notify+0xf0/0x1a0
 br_fdb_update+0x4c8/0x690
 br_handle_frame_finish+0x573/0x19b0
 br_nf_hook_thresh+0x3c6/0x4a0
 br_nf_pre_routing_finish_ipv6+0x999/0xd60
 br_nf_pre_routing_ipv6+0x37e/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+0x47f/0x820
 ret_from_fork_asm+0x1a/0x30
 </TASK>
