On a Sun IPX, during a "make build" a kernel built of 19991119 sources
failed twice at exactly the same point with

[hauke@elmo] ~ > trap type 0x2: pc=0xf011e008 npc=0xf011e00c
psr=ffffffff909010c
1<EF,S,PS>
kernel: illegal instruction trapStopped in cpp at       pv_flushcache+0x24:
wr              %o0, 0x700, %ps
r
db> t
pmap_zero_page4_4c(0x27cc000, 0xfff7, 0x210, 0x2f87, 0x28, 0x8) at pmap_zero_pa
ge4_4c+0x3c
uvm_pagezero(0xf02d4d80, 0x4d27a, 0xf01a8080, 0xf01a8080, 0x0, 0x0) at uvm_page
zero+0x18
uvm_fault(0xf02d4d80, 0x4, 0x7, 0xffffffff, 0xf01a8080, 0xf9a157b8) at uvm_faul
t+0x120c
mem_access_fault(0xf99b9960, 0x8080, 0x4e008, 0x22ffc, 0x0, 0xf9a1dfb0) at mem_
access_fault+0x1b4
normal_mem_fault(0x40918, 0x4e000, 0x4d000, 0x0, 0xffffffff, 0xf9a1dfb0) at nor
mal_mem_fault+0x28
db>

with softupdates enabled on /dev/sd1a (/var) and /dev/sd2a (/home).
The relevant excerpts from df:

Filesystem                    1K-blocks     Used    Avail Capacity  Mounted on
/dev/sd2d                       1329765   230195  1033081    18%    /usr
/dev/sd1a                        266023    94178   158543    37%    /var
/dev/sd2a                        266023    65379   187342    25%    /home
<above>:/f/bsd/sup-netbsd/src   2029769   971061   968729    50%    /usr/src
<above>:/var/obj                1237084  1065239   158543    87%    /usr/src

-- objects were written to "/var/obj", and nohup output was written to
"/home/hauke/build.out".

Disabling softupdates on /dev/sd{1,2}a "fixes" the panic.

	hauke


--
"It's never straight up and down"     (DEVO)