page fault with NetBSD 4.0 with 4.5TB filesystem

[Stephen Borrill <netbsd%precedence.co.uk@localhost>]

As described in 
http://mail-index.netbsd.org/netbsd-users/2008/09/23/msg002009.html I've got a 
4.5TB FFSv2 filesystem at a customer's site on NetBSD 4.0. I've managed to 
recreate the problem that made them power-cycle:

uvm_fault(0xc0a1ca00, 0xdeec0000, 1) -> 0xe
kernel: supervisor trap page fault, code=0
Stopped in pid 5959.1 (chmod) at        netbsd:ffs_snapremove+0x3b0: movl    0
(%ebx,%edx,1),%esi
db> bt
ffs_snapremove(d51b9f18,0,feeebb7,0,1000) at netbsd:ffs_snapremove+0x3b0
ffs_truncate(d51b9f18,0,0,0,ffffffff) at netbsd:ffs_truncate+0xe50
ufs_inactive(d4a85b40,7c9ce412,cc873200,c07a63a0,d51b9f18) at 
netbsd:ufs_inactive+0x23d
VOP_INACTIVE(d51b9f18,d3d0f5c8,d4a85c2c,c048e9a6,d51b9f18) at 
netbsd:VOP_INACTIVE+0x25
vput(d51b9f18,d4a85b74,d3d0f5c8,c07a6460,130b) at netbsd:vput+0x6e
sys___lstat30(d3d0f5c8,d4a85c48,d4a85c68,246,0) at netbsd:sys___lstat30+0x86
syscall_plain() at netbsd:syscall_plain+0x149
--- syscall (number 389) ---
0xbbbb5e4b:

So before I reboot and check out Christos' fsck patch, is there any more 
information I can extract from ddb that might be of use?

There is not (and has not been) any ffs snapshots on this fs. It's newly 
newfs'd and since then has had a rsync running to a separate server. It was up 
to about 500GB full.

--
Stephen