Netwinder locks up

[Valery Ushakov <uwe%stderr.spb.ru@localhost>]

I have a diskless netwinder that I boot may be once or twice a year
for a test.

Its kernel is a slightly trimmed down GENERIC with most FS code
disabled and with root on nfs hardcoded.

The previos kernel:

  NetBSD 10.99.10 (SERIAL_FART) #0: Wed Dec 27 22:50:05 MSK 2023

worked ok and I build a few packages with it (no small feat, given it
has 32MB RAM and the size of modern gcc).

Current kernel

  NetBSD 10.99.12 (SERIAL_FART) #0: Thu Oct 17 01:50:07 MSK 2024

on the other hand, tends to wedge randomly while going multiuser.  On
a good run it can reach the login prompt, but on most attempts it
wedges hard anywhere between "Not checking /:" and "Building
databases:".  Doesn't respond to pings, doesn't react to break (for
ddb).  Sometimes it panics early in the mutex code.  Which makes me
suspect some mutex related changes, I suppose.

Things are a bit complicated as this unit is some development oddball
that has its quirks and instabilities.  But the current clearly has
way more troble with it than can be explained away with this machine
eccentricities.

Does this ring a bell?

-uwe