kern/56536: shutdown issue in usbnet

[Thomas Klausner <wiz%NetBSD.org@localhost>]

>Number:         56536
>Category:       kern
>Synopsis:       shutdown issue in usbnet
>Confidential:   no
>Severity:       non-critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Dec 04 09:35:00 +0000 2021
>Originator:     Thomas Klausner
>Release:        NetBSD 9.99.92
>Organization:

>Environment:
	
	
Architecture: evbarm
Machine: aarch64
>Description:
On a Raspberry 3B+ running NetBSD-current from about a week ago, shutdown leads to a panic.
>How-To-Repeat:
'shutdown -p' a Raspberry Pi 3B+ (perhaps after using the LAN).

See (handcopied):

WARNING: powerdown failed
The operating system has halted.
Please press any key to reboot.
Skipping crash dump on recursive panic
panic: usbd_transfer: not done
cpu2: Begin traceback...
trace fp fff...
vpanic()
panic()
usbd_transfer()
usbd_do_request_len()
mue_csr_read.part.0()
mue_wait_for_bits()
mue_uno_mii_read_reg()
usbnet_mii_readreg()
mii_phy_tick()
ukphy_service()
mii_tick()
usbnet_tick_task()
usb_task_thread()
address 0x100 is invalid
address 0xf0 is invalid
address 0xe8 is invalid
cpu2: End traceback
vcmbox0: workqueue busy: updates stopped

From dmesg:
mue0 at uhub2 port 1
mue0: vendor 0424 (0x0424) product 7800 (0x7800), rev 2.10/3.00, addr 7
mue0: LAN7800 id 0x7800 rev 0x2
ukphy0 at mue0 phy 1: OUI 0x00800f, model 0x0013, rev. 2
ukphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseT, 1000baseT-FDX, auto
mue0: Ethernet address xx:xx:xx:xx:xx:xx


>Fix:
Yes, please.

>Unformatted: