I noticed that perhaps starting from VirtualBox 3.0.0 /etc/init.d/vboxdrv was added, in previous versions there was no such service in /etc/init.d folder.
I also noticed that /etc/init.d/vboxdrv was already added to default runlevel.
Before I was loading the kernel module with vboxdrv added to /etc/conf.d/modules, so I tried to remove the module name from this file (I try to avoid as much as possible custom config files, so, if there is a standard way to do a thing I do prefer it to all other ways).
After reboot vboxdrv was not loaded.
Trying to run /etc/init.d/vboxdrv start manually everything worked as expected, the module is loaded and VirtualBox started VM as expected.
This does not happen automatically, despite /etc/init.d/vboxdrv is on default runlevel!!!
I tried to have a look to /var/log/messages file but there were no lines about vboxdrv.
I also tried to follow boot process interactively (typing I while booting), but nothing, /etc/init.d/vboxdrv is completely ignored.
How could this be possible?
What should I check?