install/54864: A creating a file in root directory in a shell called from sysinst goes to panic

[guest01%vp.pl@localhost]

>Number:         54864
>Category:       install
>Synopsis:       A creating a file in root directory in a shell called from sysinst goes to panic
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    install-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Jan 16 19:55:00 +0000 2020
>Originator:     guest01
>Release:        http://nycdn.netbsd.org/pub/NetBSD-daily/netbsd-9/202001160600Z/images/NetBSD-9.0_RC1-amd64-install.img.gz
>Organization:
-
>Environment:
NetBSD  9.0_RC1 NetBSD 9.0_RC1 (GENERIC) #0: Thu Jan  9 17:18:43 UTC 2020  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/amd64/compile/GENERIC amd64
>Description:
You have computer booted from USB installation image and sysinst is started. When you go to shell and run command:
uname -a >> file.txt
in root directory, you will get panic message starting with:
[111.8389853] panic: ffs_newvnode:
>How-To-Repeat:
1. Boot computer with installation disk prepared form image
2. Select Install NetBSD
3. Keyboard type: US-English
4. Utility menu
5. Run /bin/sh
6. uname -a >> file.txt
   and panic message is displayed
>Fix: