kern/54956: Cannot run /usr/sbin/wsconscfg if /usr uses ZFS

[syllopsium%syllopsium.com@localhost]

>Number:         54956
>Category:       kern
>Synopsis:       Cannot run /usr/sbin/wsconscfg if /usr uses ZFS
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Feb 10 22:50:00 +0000 2020
>Originator:     Peter Kay
>Release:        9.0RC2
>Organization:
>Environment:
NetBSD localhost 9.0_RC2 NetBSD 9.0_RC2 (GENERIC) #0: Fri Jan 31 12:19:17 UTC 2020  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/amd64/compile/GENERIC amd64
>Description:
If /usr is copied to a ZFS volume, and then mounted
on boot, a few non critical programs such as /usr/sbin/wsconscfg
will not run, leaving the system with only one virtual terminal

This is not the case when /usr is an FFS filesystem

Standard install of NetBSD amd64 on a Core2Quad system with an SSD
and 8GB RAM
>How-To-Repeat:
Install NetBSD. Create ZFS pool and volume. Copy /usr (using cp -pR)
to ZFS volume, set mount option of ZFS volume to /usr, and remove
/usr from fstab.

Boot will mostly work fine, but /usr/sbin/wsconscfg will not run
despite the ZFS component loading earlier in the boot sequence
>Fix:
Either keep /usr on ZFS, or alternatively should boot critical or
important components be on a non root filesystem?

For instance, if /usr can't be mounted the absence of 
/usr/libexec/getty will stop pretty much any interaction with the
system other than a power off shutdown