LOR (swap_pager.c:1323, swap_pager.c:1838, uma_core.c:876) (current:Nov17)

Here is the stack backtrace:

lock order reversal
 1st 0xc1da318c vm object (vm object) _at_ /usr/src/sys/vm/swap_pager.c:1323
 2nd 0xc0724900 swap_pager swhash (swap_pager swhash) _at_ /usr/src/sys/vm/swap_pager.c:1838
 3rd 0xc0c358c4 vm object (vm object) _at_ /usr/src/sys/vm/uma_core.c:876
Stack backtrace:
backtrace(c0692be9,c0c358c4,c06a376c,c06a376c,c06a464d) at backtrace+0x17
witness_lock(c0c358c4,8,c06a464d,36c,1) at witness_lock+0x672
_mtx_lock_flags(c0c358c4,0,c06a464d,36c,1) at _mtx_lock_flags+0xba
obj_alloc(c0c22480,1000,c976f9db,101,c06f3f50) at obj_alloc+0x3f
slab_zalloc(c0c22480,1,c06a464d,68c,c0c22494) at slab_zalloc+0xb3
uma_zone_slab(c0c22480,1,c06a464d,68c,c0c22520) at uma_zone_slab+0xd6
uma_zalloc_internal(c0c22480,0,1,5c1,72e,c06f55a8) at uma_zalloc_internal+0x3e
uma_zalloc_arg(c0c22480,0,1,72e,2) at uma_zalloc_arg+0x3ab
swp_pager_meta_build(c1da318c,7,0,2,0) at swp_pager_meta_build+0x174
swap_pager_putpages(c1da318c,c976fbb8,8,0,c976fb20) at swap_pager_putpages+0x32d
default_pager_putpages(c1da318c,c976fbb8,8,0,c976fb20) at default_pager_putpages+0x2e
vm_pageout_flush(c976fbb8,8,0,0,c06f36a0) at vm_pageout_flush+0x17a
vm_pageout_clean(c0dae2d8,0,c06a4468,32a,0) at vm_pageout_clean+0x305
vm_pageout_scan(0,0,c06a4468,5a9,1f4) at vm_pageout_scan+0x65f
vm_pageout(0,c976fd48,c068d4ed,311,0) at vm_pageout+0x31b
fork_exit(c0625250,0,c976fd48) at fork_exit+0xb4
fork_trampoline() at fork_trampoline+0x8
--- trap 0x1, eip = 0, esp = 0xc976fd7c, ebp = 0 ---
Debugger("witness_lock")
Stopped at      Debugger+0x54:  xchgl   %ebx,in_Debugger.0
db>

I'm running the sources from yesterday, nov 17:

FreeBSD 5.1-CURRENT #0: Mon Nov 17 06:40:05 CST 2003     root_at_:/usr/obj/usr/src/sys/GALAXY