VirtualBox 4.1.22 on FreeBSD 9.0-RELEASE problem: VBoxHeadless eats 100% CPU

[Alex Chistyakov]

Hello,

My system is an amd64 box running FreeBSD 9.0-RELEASE on top of ZFS.
I try to setup a VirtualBox VM from an Ubuntu 12.04 Server
installation CD in a headless mode using VNC.
Top shows that VBoxHeadless process consumes 100% CPU almost all the
time and it takes forever to boot from the CD image:

  PID USERNAME    THR PRI NICE   SIZE    RES STATE   C   TIME   WCPU COMMAND
 1652 vbox         19  22    0   358M   170M IPRT S  3   7:18 100.00%
VBoxHeadless

I get lots of repeating "ioctl(7,0x200056c1 { IO 0x56('V'), 193, 0
},0x0) = 0 (0x0)" lines every time I try to run truss on the running
VBoxHeadless process, like this:

ioctl(7,0x200056c1 { IO 0x56('V'), 193, 0 },0x0) = 0 (0x0)
ioctl(7,0x200056c1 { IO 0x56('V'), 193, 0 },0x0) = 0 (0x0)
ioctl(7,0x200056c1 { IO 0x56('V'), 193, 0 },0x0) = 0 (0x0)
ioctl(7,0x200056c1 { IO 0x56('V'), 193, 0 },0x0) = 0 (0x0)
ioctl(7,0x200056c1 { IO 0x56('V'), 193, 0 },0x0) = 0 (0x0)
ioctl(7,0x200056c1 { IO 0x56('V'), 193, 0 },0x0) = 0 (0x0)
ioctl(7,0x200056c1 { IO 0x56('V'), 193, 0 },0x0) = 0 (0x0)
ioctl(7,0x200056c1 { IO 0x56('V'), 193, 0 },0x0) = 0 (0x0)
ioctl(7,0x200056c1 { IO 0x56('V'), 193, 0 },0x0) = 0 (0x0)
ioctl(7,0x200056c1 { IO 0x56('V'), 193, 0 },0x0) = 0 (0x0)
ioctl(7,0x200056c1 { IO 0x56('V'), 193, 0 },0x0) = 0 (0x0)

and it looks like this system call prevails in truss stats:

[root at ci ~]# wc -l truss.vbox.log
 1174962 truss.vbox.log
[root at ci ~]# cat truss.vbox.log | grep 'ioctl(7,0x200056c1' | wc -l
 1013997
[root at ci ~]#

FD 7 is /dev/vboxdrv0, does this indicate a problem in communicating
with a kernel VirtualBox driver?
What should I do to resolve this situation?

Thank you!

--
SY,
Alex