double-free after virtualbox guest additions installed

This should be 100% reproducible with VirtualBox 3.1.4. Just install arwinss (I used the current debug build ISO From the forum) under virtualbox 3.1.4. You'll need to disable USB for it to boot. The VM has 192MB RAM. Then, choose "install guest additions" which will mount the guest additions ISO under the guest, and run the installer there.

That finishes successfully. Reboot the machine, and click on start. The kernel will dump core.