panic: lock (uidinfo hash) rw does not match earlier (sleep mutex) lock

This is with HEAD built today; sources updated from cvsup4.freebsd.org
as of about 0330 hrs. US/Pacific.

It occurred on the first boot after building/installing CURRENT, and it
happens right away -- both on my laptop & my build machine (both i386;
build machine is 2x850MHz PIII; laptop is 1x2.4GHz P4); the following is
from the build machine:

/boot/kernel/acpi.ko text=0x540f8 data=0x2640+0x186c syms=[0x4+0x8b40+0x4+0xbdcd]
GDB: no debug ports present
KDB: debugger backends: ddb
KDB: current backend: ddb
Copyright (c) 1992-2008 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
        The Regents of the University of California. All rights reserved.
FreeBSD is a registered trademark of The FreeBSD Foundation.
FreeBSD 8.0-CURRENT #72: Mon Mar 17 07:59:39 PDT 2008
    root_at_freebeast.catwhisker.org:/common/S4/obj/usr/src/sys/FREEBEAST
WARNING: WITNESS option enabled, expect reduced performance.
Timecounter "i8254" frequency 1193182 Hz quality 0
CPU: Intel Pentium III (846.32-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0x683  Stepping = 3
  Features=0x387fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,PN,MMX,FXSR,SSE>
real memory  = 2147418112 (2047 MB)
avail memory = 2093940736 (1996 MB)
ACPI APIC Table: <Intel  N440BX  >
FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
 cpu0 (BSP): APIC ID:  1
 cpu1 (AP): APIC ID:  0
panic: lock (uidinfo hash) rw does not match earlier (sleep mutex) lock
cpuid = 0
KDB: enter: panic
[thread pid 0 tid 0 ]
Stopped at      kdb_enter+0x3a: movl    $0,kdb_why
db> bt
cing pid 0 tid 0 td 0xc0c11470
kdb_enter(c0af1957,c0af1957,c0af64de,c1020c94,0,...) at kdb_enter+0x3a
panic(c0af64de,c0af1159,c0afccb7,c0b13b15,c0c12c8c,...) at panic+0x12c
enroll(c1020cd8,c075ce2a,c146d5a0,0,c0af1159,...) at enroll+0xe1
witness_init(c0c12c8c,c0bca2cc,c1020cf0) at witness_init+0x109
lock_init(c0c12c8c,c0baf888,c0af1159,0,2a0000) at lock_init+0x89
rw_init_flags(c0c12c8c,c0af1159,0,c1020d44,c0763a15,...) at rw_init_flags+0xaf
uihashinit(c0af0c88,290,c0763bd0,c0763d00,c0763a20,...) at uihashinit+0x51
procinit(c0c12b30,4,c0aec794,176,1,...) at procinit+0x125
proc0_init(0,101ec00,101ec00,101e000,1025000,...) at proc0_init+0x46
mi_startup() at mi_startup+0x96
begin() at begin+0x2c
db> ps
  pid  ppid  pgrp   uid   state   wmesg     wchan    cmd
    0     0     0     0
db> show locks
exclusive sleep mutex Giant r = 0 (0xc0c12b30) locked _at_ /usr/src/sys/kern/kern_linker.c:295
db> 


(Laptop's results look the same as the above at first blush.  Note
that the build machine runs headless -- it has neither a monitor
nor a keyboard connected now, and these are only connected during
unusual circumstances.)

As usual, I'm willing to try patches or circumventions.  I have
serial console access to both the laptop & the build machine, and
each has a local private mirror of the FreeBSD CVS repository.

Peace,
david
-- 
David H. Wolfskill				david_at_catwhisker.org
I submit that "conspiracy" would be an appropriate collective noun for cats.

See http://www.catwhisker.org/~david/publickey.gpg for my public key.