SunOS 4.1 kernel panic

[Eirik Fuller]

Has anyone else seen SunOS 4.1 panic while trying to write to a tmpfs?

We got this message:

vmunix: assertion failed: nzero > 0 && 			    segmap_offset + zoffset + nzero <= MAXBSIZE, file: ../../tmpfs/tmp_vnodeops.c, line: 367

This is the stack trace from adb:

_panic(0xf80c5e65,0xf80c8b8a,0xf80c8bca,0x16f,0xffffffff,0xf82cec70) + 6c
_assfail(0xf80c8b8a,0xf80c8bca,0x16f,0x1fff,0xf82ceea4,0x2000) + 3c
_rwtmp(0xff0c80e0,0xff0f29a0,0xf82ceeac,0x1,0xd,0x0) + 574
_tmp_rdwr(0xff0c80e0,0xf82ceeac,0x1,0x1,0xff10840c,0xff0f29a0) + 50
_vno_rw(0xf8122ec4,0x1,0xf82ceeac,0x47d,0xff0f29b8,0x1) + a4
_rwuio(0xf8122ec4,0xf82ceeac,0xf82ceea4,0x47d,0x47d,0xf82ceeac) + 2b0
_write(0xf82cefe0,0x20,0xf80c49b0,0xf80c49d0,0xf82cf000,0xf80c49d0) + 34
_syscall(0xf82cf000) + 3b4

This happened during a cp command whose last arg was "/tmp".  The other
args were names of plain NFS files from an expanded wildcard pattern.

The machine is a Sun 4/280 with its swap partition on this disk: vmunix:
xy0: <Hitachi DK815-10 cyl 1735 alt 2 hd 15 sec 67> vmunix: swap on xy0b
fstype spec size 144720K vmunix: dump on xy0b fstype spec size 144696K

Any hints about dodging this problem, particularly kernel patches, would
be appreciated.  "Mount /tmp elsewhere" is not a response I hope to see.
:-)

Eirik