NFS root doen't work on next68k after NetBSD 9.2

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

In pullup-9 back in source-changes@ on March 2021:
 https://mail-index.netbsd.org/source-changes/2021/03/07/msg127582.html

> Module Name:	src
> Committed By:	martin
> Date:		Sun Mar  7 19:04:31 UTC 2021
> 
> Modified Files:
> 	src/sys/netinet [netbsd-9]: ip6.h ip_input.c tcp_subr.c
> 	src/sys/netinet6 [netbsd-9]: ip6_id.c ip6_var.h
> 
> Log Message:
> Pull up following revision(s) (requested by christos in ticket #1226):
> 
> 	sys/netinet6/ip6_id.c: revision 1.19-1.21
> 	sys/netinet6/ip6_var.h: revision 1.88
> 	sys/netinet/ip_input.c: revision 1.400
> 	sys/netinet/tcp_subr.c: revision 1.285
> 	sys/netinet/ip6.h: revision 1.30
> 
> netinet: Enable random IP fragment ids by default (from riastradh)

I've investigated a problem that NetBSD/next68k 9.3 GENERIC doesn't
boot on NFS root, and then it turns out the above "ip_do_randomid"
change in this pullup request cause the problem per git-bisect.

Just reverting the following line
 https://github.com/NetBSD/src/commit/de6d2db7d06c8e3c0e35995722ebaa259b78c2ba#diff-8a50bc8e5e7080ceff91c3ac7e159fc046834f0dc2096a060a79bb122d38e717L171
>> int ip_do_randomid = 1;
or changing do_ip_randomid=0 on DDB makes NetBSD/next68k 9.3 GENERIC
work on NFS root again:

---
[   1.0000000] Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
[   1.0000000]     2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017,
[   1.0000000]     2018, 2019, 2020, 2021, 2022
[   1.0000000]     The NetBSD Foundation, Inc.  All rights reserved.
[   1.0000000] Copyright (c) 1982, 1986, 1989, 1991, 1993
[   1.0000000]     The Regents of the University of California.  All rights reserved.

[   1.0000000] NetBSD 9.3 (GENERIC) #6: Thu Jan 26 03:25:33 JST 2023
[   1.0000000] 	tsutsui@mirage:/s/netbsd-9/src/sys/arch/next68k/compile/GENERIC
[   1.0000000] NeXT/MC68040 CPU+MMU+FPU, 4k on-chip physical I/D caches
[   1.0000000] total memory = 32760 KB
[   1.0000000] avail memory = 27548 KB

(..snip..)

[   4.7900080] boot device: xe0
[   4.8000080] root on xe0
[   4.8100080] nfs_boot: trying DHCP/BOOTP
[  22.8300080] nfs_boot: timeout...
[  27.8400080] nfs_boot: timeout...
[  32.8500080] nfs_boot: timeout...
[  37.8600080] Supported file systems: mfs ffs nfs umap procfs overlay null kernfs fdesc union tmpfs puffs ptyfs
[  37.9300080] no file system for xe0
[  37.9400080] cannot mount root, error = 79
[  37.9500080] root device (default xe0): 
[  37.9800080] dump device: 
[  38.0000080] file system (default generic): 
[  38.0200080] root on xe0
[  38.0300080] nfs_boot: trying DHCP/BOOTP
Stopped in pid 0.2 (system) at  netbsd:cpu_Debugger+0x6:        unlk    a6
db> write ip_do_randomid 0
netbsd:ip_do_randomid           = 0
db> c
nfs_boot: DHCP next-server: 192.168.20.1
[  41.0600080] nfs_boot: my_domain=ceres.dti.ne.jp
[  41.0700080] nfs_boot: my_addr=192.168.20.77
[  41.0800080] nfs_boot: my_mask=255.255.255.0
[  41.0900080] nfs_boot: gateway=192.168.20.1
[  53.1600080] root on mirage:/r/export/NetBSD/next68k/root
[  53.1700080] root file system type: nfs
[  53.1800080] kern.module.path=/stand/next68k/9.3/modules
[  53.2100080] init path (default /sbin/init): 
[  53.2400080] init: trying /sbin/init
/etc/rc.conf is not configured.  Multiuser boot aborted.
Enter pathname of shell or RETURN for /bin/sh: 
---
 
Somehow NetBSD/next68k 10.99.2 GENERIC works with ip_do_randomid=1,
but is there any possible workaround for this issue on netbsd-9?

(Note several other next68k specific fixes are necessary to make
 next68k GENERIC kernel working state:
 https://mail-index.netbsd.org/port-next68k/2023/01/20/msg000043.html )

Thanks,
---
Izumi Tsutsui