panic: pmap_enter: attempted pmap_enter on 4MB page

I've been getting this panic a lot in the past week.  Unfortunately it's on my 
file server so I can't use gdb to get more details than what ddb provides 
(the kernel is on the machine that's panic'd).  This is a UP x86 box.  The 
stack trace is:

pmap_enter
kmem_malloc
page_alloc
slab_zalloc
uma_zone_slab
uma_zalloc_bucket
uma_zalloc_arg
uma_zalloc_arg
ffs_vget
ufs_lookup
ufs_vnoperate
vfs_cache_lookup
ufs_voperate
lookup
nfs_namei
nfsrv_lookup
nfssvc_nfsd
nfssvc

Contact me for more details. This really needs to be fixed.

	Sam