head panic: mutex Giant owned at /d2/emaste/svn-head/src/sys/geom/geom_dev.c:184

I haven't looked into this yet, but just got the following panic on boot
from a GENERIC kernel built from svn head ~ 1 hour ago:

Loading configuration files.
panic: mutex Giant owned at /d2/emaste/svn-head/src/sys/geom/geom_dev.c:184
cpuid = 0
KDB: enter: panic
[thread pid 35 tid 100069 ]
Stopped at      kdb_enter+0x3a: movl    $0,kdb_why
db>

db> bt
Tracing pid 35 tid 100069 td 0xc7119230
kdb_enter(c0b46154,c0b46154,c0b44be1,e93899a4,0,...) at kdb_enter+0x3a
panic(c0b44be1,c0b64e7b,c0b3daac,b8,e93899e0,...) at panic+0x12c
_mtx_assert(c0c89570,0,c0b3daac,b8,2000,...) at _mtx_assert+0x127
g_dev_open(c707ad00,1,2000,c7119230,4,...) at g_dev_open+0xb4
devfs_open(e9389acc,c7119230,e9389ba8,0,e9389af4,...) at devfs_open+0xdf
VOP_OPEN_APV(c0c17580,e9389acc,c7119230,e9389a54,c710a860,...) at VOP_OPEN_APV+0xa5
vn_open_cred(e9389ba8,e9389c5c,9cd,c648b800,c70d7818,...) at vn_open_cred+0x429
vn_open(e9389ba8,e9389c5c,9cd,c70d7818,0,...) at vn_open+0x33
kern_openat(c7119230,ffffff9c,bfbfef70,0,1,...) at kern_openat+0x106
kern_open(c7119230,bfbfef70,0,0,80489df,...) at kern_open+0x35
open(c7119230,e9389cf8,c,c7119230,c0c1aad8,...) at open+0x30
syscall(e9389d38) at syscall+0x2a3
Xint0x80_syscall() at Xint0x80_syscall+0x20
--- syscall (5, FreeBSD ELF32, open), eip = 0x28159cb3, esp = 0xbfbfee2c, ebp = 0xbfbfee88 ---

- Ed