LOR vm_object.c:434 vm_kern.c:329

I got this LOR when I started X.

Kernel rev:
FreeBSD roark.gnf.org 5.1-CURRENT FreeBSD 5.1-CURRENT #0: Thu Aug 21 09:39:38 PDT 2003     gtetlow_at_roark.gnf.org:/local/usr.obj/local/usr.src/sys/ROARK  i386

lock order reversal
 1st 0xc6856de0 vm object (vm object) _at_ /local/usr.src/sys/vm/vm_object.c:434
 2nd 0xc082f110 system map (system map) _at_ /local/usr.src/sys/vm/vm_kern.c:329
Stack backtrace:
backtrace(c033da41,c082f110,c034916c,c034916c,c0349001) at backtrace+0x17
witness_lock(c082f110,8,c0349001,149,c082f0b0) at witness_lock+0x671
_mtx_lock_flags(c082f110,0,c0349001,149,101) at _mtx_lock_flags+0xb2
_vm_map_lock(c082f0b0,c0349001,149,c0397d08,c0397d30) at _vm_map_lock+0x36
kmem_malloc(c082f0b0,1000,101,e7866b18,c02c59e0) at kmem_malloc+0x3a
page_alloc(c083a200,1000,e7866b0b,101,0) at page_alloc+0x27
slab_zalloc(c083a200,101,c083a214,8,c034a980) at slab_zalloc+0xc0
uma_zone_slab(c083a200,101,c034a980,695,0) at uma_zone_slab+0xd4
uma_zalloc_internal(c083a200,0,101,719,0) at uma_zalloc_internal+0x4f
uma_zfree_arg(c083a800,c686e000,0,e7866bc4,c02add19) at uma_zfree_arg+0x2a0
dev_pager_putfake(c686e000,0,c03486e4,bd,c6856de0) at dev_pager_putfake+0x34
dev_pager_dealloc(c6856de0,1,c034a909,104,0) at dev_pager_dealloc+0xb9
vm_pager_deallocate(c6856de0,0,c0349abb,261,1b2) at vm_pager_deallocate+0x3d
vm_object_terminate(c6856de0,0,c0349abb,1b2,c680d078) at vm_object_terminate+0x1e3
vm_object_deallocate(c6856de0,c67dad98,c6856de0,c67dad98,e7866ca0) at vm_object_deallocate+0x359
vm_map_entry_delete(c6490c00,c67dad98,c03491e2,8a4,c01cd655) at vm_map_entry_delete+0x3b
vm_map_delete(c6490c00,282e5000,282e6000,1000,282e5000) at vm_map_delete+0x3c0
vm_map_remove(c6490c00,282e5000,282e6000,0,c67d69e0) at vm_map_remove+0x55
munmap(c648b5f0,e7866d14,c034edf9,3eb,2) at munmap+0x9e
syscall(2f,2f,2f,f8000,1000) at syscall+0x253
Xint0x80_syscall() at Xint0x80_syscall+0x1d
--- syscall (73), eip = 0x28256c2f, esp = 0xbfbff99c, ebp = 0xbfbff9c8 ---