kern/54023: assertion panic during shutdown

[Hauke Fath <hf%spg.tu-darmstadt.de@localhost>]

>Number:         54023
>Category:       kern
>Synopsis:       assertion panic during shutdown
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Feb 27 15:45:00 +0000 2019
>Originator:     Hauke Fath
>Release:        NetBSD 8.99.34
>Organization:
Technische Universitaet Darmstadt
>Environment:
	
	
System: NetBSD Aibel.nt.e-technik.tu-darmstadt.de 8.99.34 NetBSD 8.99.34 (PINE64-$Revision$) #0: Tue Feb 26 14:51:31 CET 2019 hf@Hochstuhl:/var/obj/netbsd-builds/developer/evbarm/sys/arch/evbarm/compile/PINE64 evbarm
Architecture: aarch64
Machine: evbarm
>Description:

	This pinebook panics during shutdown/reboot with an assertion
	failure:

kernel disgnostic assertion "xfer-ux_status != USBD_CANCELLED" failed: file "[...]/sys/dev/usb/ehci.c", line 3264

	Full stack trace at
	<https://www2.nt.tu-darmstadt.de/~hf/netbsd/pinebook/usb_ehci_c-assertion.jpg>

	It then locks up hard trying to dump core, and has to be
	powered off.

	>
How-To-Repeat:

	Reboot pinebook.

	<code/input/activities to reproduce the problem (multiple lines)>
>Fix:
	No idea.
	
	

>Unformatted: