INFO: task kworker/0:2:792 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:2     state:D stack:22616 pid:792   tgid:792   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+0x4bc/0x870
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e33d660 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by kswapd0/90:
2 locks held by kswapd1/91:
3 locks held by kworker/1:2/973:
 #0: ffff88801a875548 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900067a7ba0 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8e3430f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730
3 locks held by kworker/u9:5/4576:
 #0: ffff88801a889148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90002e77ba0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f7452c8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60
1 lock held by klogd/5284:
4 locks held by udevd/5295:
3 locks held by dhcpcd/5593:
2 locks held by getty/5680:
 #0: ffff88802870f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900025302f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
1 lock held by syz-executor/5778:
1 lock held by syz-executor/7380:
 #0: ffffffff8f7452c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
3 locks held by kworker/0:5/7526:
 #0: ffff88801a875548 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90003c07ba0 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f7452c8 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20
4 locks held by syz.2.1094/8376:
 #0: ffff8880243c4dc8 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x510
 #1: ffff8880243c40b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x66a/0x1330
 #2: ffffffff8f8a9b88 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x230
 #3: ffff88810b485b38 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x70/0x680
2 locks held by syz-executor/8384:
1 lock held by syz-executor/8386:
2 locks held by dhcpcd/8392:

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

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+0xf60/0xfa0
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 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: 8385 Comm: kworker/u9:7 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 cfg80211_wiphy_work
RIP: 0010:validate_chain+0x1/0x2140
Code: 89 e6 4c 89 ff 29 f5 0f 82 91 fe ff ff eb b3 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 <41> 57 41 56 41 55 41 54 53 48 81 ec e0 00 00 00 49 89 cf 65 48 8b
RSP: 0018:ffffc900000077b8 EFLAGS: 00000086
RAX: ffffffff936cc8a8 RBX: 0000000000000004 RCX: 750056423fe9602d
RDX: 0000000000000000 RSI: ffff88802224a8d0 RDI: ffff888022249d00
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8173bd25
R10: ffffc90000007a18 R11: ffffffff81ac44a0 R12: 00000000312ea683
R13: ffff88802224a830 R14: ffff88802224a8d0 R15: 750056423fe9602d
FS:  0000000000000000(0000) GS:ffff8880b83e0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbc1236abd0 CR3: 000000010edc8000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 __lock_acquire+0xab9/0xd20
 lock_acquire+0x120/0x360
 unwind_next_frame+0xc2/0x2390
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 ref_tracker_free+0xef/0x7d0
 dst_destroy+0x10f/0x350
 rcu_core+0xcab/0x1770
 handle_softirqs+0x286/0x870
 do_softirq+0xec/0x180
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x17d/0x1c0
 ieee80211_ibss_work+0x300/0x1060
 cfg80211_wiphy_work+0x2bb/0x470
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 ret_from_fork_asm+0x1a/0x30
 </TASK>
