kern/57691: NFS client regression with macOS 14 server

[schmonz%NetBSD.org@localhost]

>Number:         57691
>Category:       kern
>Synopsis:       NFS client regression with macOS 14 server
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Nov 10 19:10:00 +0000 2023
>Originator:     Amitai Schleier
>Release:        NetBSD 9.3 and 10.0_BETA
>Organization:
Latent Agility
>Environment:
NetBSD netbsd9-amd64.pet-power-plant.local 9.3 NetBSD 9.3 (GENERIC) #0: Thu Aug  4 15:30:37 UTC 2022  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/amd64/compile/GENERIC amd64

NetBSD netbsd10-arm64.magnetic-babysitter.local 10.0_BETA NetBSD 10.0_BETA (GENERIC64) #0: Wed Feb  1 19:00:10 UTC 2023  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/evbarm/compile/GENERIC64 evbarm
>Description:
After upgrading my NFS server from macOS 13 to 14, I started
encountering this error regularly on my netbsd-9 and -10 clients,
in ordinary pkgsrc usage:

    bmake: Cannot open `.' (Invalid argument)

Once this has happened in a subtree of the NFS mount, file operations
in that subtree all fail until the NetBSD client (a VM on the same
physical machine) has been rebooted.

I didn't have this interoperability problem with macOS 13's NFS
server, and I haven't been able to reproduce this problem with any
of the other OSes (FreeBSD, OpenBSD, Tribblix, many Linuxes) also
running in VMs on the same machine.

NFS in this state has become unusable for me.
>How-To-Repeat:
On either netbsd-9 or netbsd-10, with an NFS mount in $HOME/trees
from a macOS 14 host:

    cd $HOME/trees/pkgsrc-cvs/shells/oksh
    bmake

ktrace of that:
https://netbsd.schmonz.com/tmp/nfs/make-in-pkgsrc-shells-oksh-over-nfs-kdump.txt

tcpdump of "ls" after the problem has manifested:
https://netbsd.schmonz.com/tmp/nfs/ls-after-the-problem-tcpdump.txt
>Fix:
none known