9p regression linux-next next-20230327

[Luis Chamberlain]

kdevops uses 9p for its client / host setup to enable rapid kernel
development on guests using the host to compile / guest to install
a read-only-mount.

I updated the kernel today to next-20230327 and see the 9p mount won't
come up and so boot fails. I'm starting to bisect and see next-20230301
was OK. So at least have:

next-20230301: GOOD                                                             
next-20230315: GOOD
next-20230327: BAD

Once I narrow this down a bit further I'll poke back.

What sort of tests are run for 9p before some development changes get
pushed into a tree that lands on linux-next? If none exists, simply
testing 'make linux' works with kdevops could perhaps be a start.

  Luis