Updated: I've rephrased this problem as I understand it a bit more now (and have encountered another problem).

I'm using a Fedora 15 guest on a Windows 7 host using VirtualBox. I am trying to mount a partition on the host PC as a shared folder for use in the guest.

The folder appears in /media and is accessible when I use the auto-mount feature when setting up the shared folder, but when I attempt to mount without auto-mount I get the following error:

$ sudo mount.vboxsf data /mnt/host_data
/sbin/mount.vboxsf: Could not add an entry to the mount table.: Invalid argument

In addition a popup appears (part of Fedora/GNOME) reporting a crash in the kernel package:

WARNING: at lib/list_debug.c:26 __list_add+0x3e/0x81()

However the shared folder seems to work, I can certainly browse it (although everything seems to be executable, probably down to a Windows host).

Is there something wrong with what I'm doing or is this a bug (and in which case should it be reported to the Linux Kernel team or VirtualBox)?