Possibly triggered by a combination of USB disconnect/connect + suspend/resume events. vsp@google.com reports that he plugged/unplugged USB-C connectors that hook up external displays + input devices.

Board: Eve
Version: 11021.56.0

Crash report at https://crash.corp.google.com/browse?stbtiq=f82dc39cf8224106
Corresponding feedback report (taken after reboot): https://listnr.corp.google.com/product/208/report/85795674257?dateRange=All

Hung task stack trace per crash report:

<3>[86041.958215] INFO: task kworker/1:2:9498 blocked for more than 120 seconds.
<3>[86041.958234] Not tainted 4.4.153-15155-g656ec00c3ce2 #1
<3>[86041.958241] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
<6>[86041.958249] kworker/1:2 D 0000000000000000 0 9498 2 0x00000000
<6>[86041.958282] Workqueue: pm pm_runtime_work
<4>[86041.958294] ffff88042f80ed00 ffff88047ec95900 ffff88046cad2ac0 ffff880384374740
<4>[86041.958314] 0000000000000001 ffff88000333f6a0 ffffffffbdfe7e7a ffffffffbdfec524
<4>[86041.958333] 00000000bdfec530 ffffffffbdfec524 ffffffffbdfec530 e3773d1649d0c350
<4>[86041.958353] Call Trace:
<4>[86041.958370] [<ffffffffbdfe7e7a>] ? __schedule+0x3d6/0x923
<4>[86041.958383] [<ffffffffbdfec524>] ? __switch_to_asm+0x34/0x70
<4>[86041.958394] [<ffffffffbdfec524>] ? __switch_to_asm+0x34/0x70
<4>[86041.958404] [<ffffffffbdfec530>] ? __switch_to_asm+0x40/0x70
<4>[86041.958414] [<ffffffffbdfe7a68>] schedule+0x40/0x7c
<4>[86041.958426] [<ffffffffbdfea361>] schedule_timeout+0x3a/0x5d9
<4>[86041.958439] [<ffffffffbd96aa30>] ? update_cfs_rq_load_avg+0x6e/0x2f8
<4>[86041.958451] [<ffffffffbdfe8ffa>] do_wait_for_common+0xab/0x131
<4>[86041.958462] [<ffffffffbdfea327>] ? console_conditional_schedule+0x2d/0x2d
<4>[86041.958474] [<ffffffffbd960e23>] ? scheduler_tick+0xd6/0xd6
<4>[86041.958484] [<ffffffffbdfe8e26>] wait_for_common+0x4c/0x63
<4>[86041.958495] [<ffffffffbdfe8dd8>] wait_for_completion+0x1b/0x1d
<4>[86041.958508] [<ffffffffbdd7501f>] xhci_stop_device+0x134/0x16e
<4>[86041.958521] [<ffffffffbdd74081>] xhci_hub_control+0x4ca/0x12bf
<4>[86041.958533] [<ffffffffbd9615dd>] ? __might_sleep+0x41/0x7d
<4>[86041.958543] [<ffffffffbdfe7ee1>] ? __schedule+0x43d/0x923
<4>[86041.958555] [<ffffffffbdd4316a>] usb_hcd_submit_urb+0x504/0x776
<4>[86041.958566] [<ffffffffbd8fcdb1>] ? SyS_alarm+0x12/0x12
<4>[86041.958578] [<ffffffffbdd457c2>] usb_submit_urb+0x4fd/0x52c
<4>[86041.958590] [<ffffffffbd9615dd>] ? __might_sleep+0x41/0x7d
<4>[86041.958602] [<ffffffffbdd4602e>] usb_start_wait_urb+0x52/0xd5
<4>[86041.958614] [<ffffffffbdd45e10>] usb_control_msg+0xc5/0x122
<4>[86041.958628] [<ffffffffbdd3c010>] set_port_feature+0x31/0x37
<4>[86041.958641] [<ffffffffbdd3cf72>] usb_port_suspend+0x197/0x275
<4>[86041.958653] [<ffffffffbdd51659>] generic_suspend+0x27/0x30
<4>[86041.958666] [<ffffffffbdd48fe1>] usb_suspend_both+0x144/0x21b
<4>[86041.958681] [<ffffffffbdd494af>] ? usb_autopm_get_interface_no_resume+0x2c/0x2c
<4>[86041.958694] [<ffffffffbdd494e1>] usb_runtime_suspend+0x32/0x5c
<4>[86041.958706] [<ffffffffbdcd2e52>] __rpm_callback+0xd6/0x185
<4>[86041.958720] [<ffffffffbdd494af>] ? usb_autopm_get_interface_no_resume+0x2c/0x2c
<4>[86041.958731] [<ffffffffbdcd2caf>] rpm_callback+0x27/0x7e
<4>[86041.958745] [<ffffffffbde8366c>] rpm_suspend+0x261/0x418
<4>[86041.958759] [<ffffffffbdd495fd>] ? usb_runtime_resume+0x1c/0x1c
<4>[86041.958773] [<ffffffffbde8393e>] __pm_runtime_suspend+0x90/0xb9
<4>[86041.958785] [<ffffffffbdd495fd>] ? usb_runtime_resume+0x1c/0x1c
<4>[86041.958797] [<ffffffffbdd49625>] usb_runtime_idle+0x28/0x2e
<4>[86041.958808] [<ffffffffbdcd2e52>] __rpm_callback+0xd6/0x185
<4>[86041.958821] [<ffffffffbdcd1f35>] rpm_idle+0x107/0x1ec
<4>[86041.958834] [<ffffffffbdcd28b7>] pm_runtime_work+0x67/0x93
<4>[86041.958846] [<ffffffffbd95e76e>] worker_thread+0x25f/0x77a
<4>[86041.958860] [<ffffffffbd95e50f>] ? list_move_tail+0x26/0x26
<4>[86041.958875] [<ffffffffbd8cff74>] kthread+0xb9/0xc9
<4>[86041.958893] [<ffffffffbdfec530>] ? __switch_to_asm+0x40/0x70
<4>[86041.958909] [<ffffffffbd8cfebb>] ? rcu_read_unlock_sched_notrace+0x48/0x48
<4>[86041.958921] [<ffffffffbdfec5ae>] ret_from_fork+0x4e/0x80
<4>[86041.958933] [<ffffffffbd8cfebb>] ? rcu_read_unlock_sched_notrace+0x48/0x48