install/54863: Editing disklabel partitions in utility menu of sysinst goes to panic

[guest01%vp.pl@localhost]

>Number:         54863
>Category:       install
>Synopsis:       Editing disklabel partitions in utility menu of 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 19:40:00 +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:
When you try to edit any disklabel partiion in utility menu os sysinst you get message starting with:

[411.1746730] panic: ffs_newvnode: dup alloc ino=10730 on /: mode 100644/100644 gen 3f229c94/3f229c94 size 29 blocks 4
>How-To-Repeat:
First create partitions on entire disk with default partition sizes:
Start an installation of NetBSD 9.0_RC1:
1. Boot computer with installation disk prepared form image
2. Select Install NetBSD
3. Keyboard type: US-English
4. Install NetBSD to hard disk
5. Shall we continue ? Yes
6. On which disk do you want to install NetBSD ? wd0 (149G)
7. This is the correct geometry
8. Use the entire disk
9. Use default partition sizes
10. Partition sizes ok
11. Shall we continue ? Yes
12. Selected bootblock: BIOS console
    Continue
13. Abandon installation
You have partitioned disk.

Next go to Utility menu:
1. Utility menu
2. Partition a disk
3. b: wda on/(FFSv2)(unused)     145GB
4. a: Edit
   and panic is displayed
>Fix: