shutdown -p now crashes

[Ganbold]

Hi,

Few hours ago I have updated my machine to latest RELENG_7.
daemon% uname -an
FreeBSD daemon.micom.mng.net 7.1-PRERELEASE FreeBSD 7.1-PRERELEASE #6: 
Tue Nov 18 02:05:57 ULAT 2008 
tsgan at daemon.micom.mng.net:/usr/obj/usr/src/sys/GDAEMON  i386
daemon%

When I try to issue command shutdown -p now, system paniced.
...
(kgdb) where
#0  doadump () at pcpu.h:196
#1  0xc062ba67 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:418
#2  0xc062bd72 in panic (fmt=Variable "fmt" is not available.
) at /usr/src/sys/kern/kern_shutdown.c:574
#3  0xc06ab8b3 in vput (vp=0xc3d11ac8) at /usr/src/sys/kern/vfs_subr.c:2202
#4  0xc06a69e6 in dounmount (mp=0xc3e59b30, flags=524288, td=0xc3b31d20) 
at /usr/src/sys/kern/vfs_mount.c:1288
#5  0xc06aa493 in vfs_unmountall () at /usr/src/sys/kern/vfs_subr.c:2939
#6  0xc062b7f4 in boot (howto=16392) at 
/usr/src/sys/kern/kern_shutdown.c:400
#7  0xc062bc17 in reboot (td=0xc3b31d20, uap=0xeef55cfc) at 
/usr/src/sys/kern/kern_shutdown.c:172
#8  0xc08171f5 in syscall (frame=0xeef55d38) at 
/usr/src/sys/i386/i386/trap.c:1090
#9  0xc07fd710 in Xint0x80_syscall () at 
/usr/src/sys/i386/i386/exception.s:255
#10 0x00000033 in ?? ()
(kgdb)
...

Is this known issue?

thanks,

Ganbold

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