I was copying files between directories on an SMBFS mounted share and  
died.

simple_lock: locking against myself
lock: 0xd33a4070, currently at: /usr/src/sys/uvm/uvm_readahead.c:131  
on CPU 0
last locked: /usr/src/sys/uvm_uvm_vnode.c:312
last unlocked: /usr/src/sys/uvm/uvm_vnode.c:308
ra:statrtio+0x82
uvm_ra_request+0x162
uvn_get+0xba
uvm_fault+0xecc
trap() at netbsd:trap+0x36f
--- trap (number 6) ---
i386_copyin+0x3c
mb_put_uio+0x70
smb_smb_writex+0x13b
smb_write+0x52
smbfs_writevnode+0x102
smbfs_write+0x2d
VOP_WRITE+0x34
vn_write+0xc6
dofilewrite+0x8d
sys_write+0x72
syscall_plain+0x1a5
--- syscall (number 4) ---

If I get a succesful dump I'll post back with the trace after I  
finish what I was working on.