Panic on 8-STABLE at boot

Tue Jun 29 16:22:15 UTC 2010

i've got a panic with zfs only machine so i decided to build a witness kernel
and just after the first reboot:
http://img190.imageshack.us/img190/3314/panicflowtable2.jpg

the second boot: no prob

uname -a
FreeBSD cg196.security-mail.net 8.1-PRERELEASE FreeBSD 8.1-PRERELEASE
#8: Tue Jun 29 14:30:12 CEST 2010
root at cg196.security-mail.net:/usr/obj/usr/src/sys/SECUMAIL  amd64

dmesg: http://freelooser.fr/freebsd/dmesg.cg196.2010-06-29.log
conf:http://freelooser.fr/freebsd/SECUMAIL.txt