USB devices cannot be connected on Fedora 11 host - should not be using /proc/bus/usb

[Robert Hancock]

With the default permissions in Fedora 11 VirtualBox is unable to connect any USB devices to guests (the devices show up in the list but are all grayed out). It appears this is because all the /proc/bus/usb files are owned by root and inaccessible. Doing a chgrp/chmod of the files to be owned by vboxusers group and readable/writable by the group seems to allow it to work. Unmounting /proc/bus/usb entirely also seems to allow it to work. (It seems that it's mounted by /etc/rc.sysinit.)

Apparently VirtualBox uses /proc/bus/usb (which is deprecated) if it's available, but doesn't check if the permissions actually allow it to be used. It seems the newer /dev/bus/usb is only used if /proc/bus/usb is entirely unmounted. Seems like it should be the other way around and /dev/bus/usb should be used unless it's not present.

[Alex Villacís Lasso]

Replying to robhancock:

Apparently VirtualBox uses /proc/bus/usb (which is deprecated) if it's available, but doesn't check if the permissions actually allow it to be used. It seems the newer /dev/bus/usb is only used if /proc/bus/usb is entirely unmounted. Seems like it should be the other way around and /dev/bus/usb should be used unless it's not present.

This bug is still present in VirtualBox 3.0.6. Same symptoms and same workarounds apply. Tested on Fedora 10 host, WinXP-SP2 guest.

[Frank Mehnert]

The next release will allow to override the default.

[Mark Scarton]

This bug is still present in VirtualBox 3.0.10. I found this to be necessary for RHEL 5.4 host running a Windows XP guest after upgrading from 3.0.6 to 3.0.10.The alternative solutions altering the udev permissions did not work, probably because /proc is being used in lieu of /dev even though it has been deprecated.

By the way, the site is littered with defects, issues, and forum discussions regarding USB device management problems. For examples, please see 5249, 3394, and ​http://forums.virtualbox.org/viewtopic.php?f=7&t=19381&p=83833&hilit=opensuse+usbfs#p83833. I have to believe that a contributing factor is that udev is not being used in a fashion consistent with current implementation standards, per the use of /dev/bus/usb. Fixing this would be of great benefit to allow of us, even if the fix is simply to expose an operational control allowing us to moderate which device access is to be used.

[Michael Thayer]

Is this still relevant with current distributions and versions of VirtualBox?

[Robert Hancock]

It appears /proc/bus/usb is no longer mounted automatically anymore as of Fedora 14 (possibly earlier) so the problem doesn't show up there. Not sure if any of this handling has changed in VirtualBox, however if it is still preferably using /proc/bus/usb if available then this should likely be changed as it will still cause problems on older distributions.

[Michael Thayer]

Perhaps refining the test to check whether the devices under /proc/bus/usb are writeable would be a better solution.