Created attachment 258351 [details]
logs from boot through attempted-poweroff

This bug has a few symptoms, which I will describe in chronological
order (not in order of severity).

I get periodic complaints in my system logs about a kworker blocking
for more than 120 seconds. Each instance includes a stack trace. In
the attached logfile, this starts at timestamp 245.426296 on line
1136, and continues throughout.

wpa_supplicant refuses to die, even after root-level processes send
it SIGKILL multiple times. See timestamps 1209.706528, 1299.955722,
1390.206410, and 1480.455734.

After the journal stops and the system reports it has finished the
final step of shutdown, the computer still remains on. I left it like
this for several minutes with no change until I forced the computer
to power off by holding down the power button. (This means I cannot
reboot the computer remotely.)

Oddly enough, I can still use wi-fi just fine. Upload and download
speeds are not perceptibly affected, and neither is latency. It is
only when I try to STOP using wi-fi that the bug visibly affects
anything outside of system logs.

The bug occurs on Linux 4.13.1 but not 4.12.12, so I will be using
4.12.12 until I need to gather more info or until this is fixed.

Here's what "lspci -knn" says about my wi-fi card:

02:00.0 Network controller [0280]: Qualcomm Atheros QCA9377 802.11ac Wireless Network Adapter [168c:0042] (rev 31)
        Subsystem: Foxconn International, Inc. QCA9377 802.11ac Wireless Network Adapter [105b:e0a1]
        Kernel driver in use: ath10k_pci
        Kernel modules: ath10k_pci

Let me know if you need any more info.