I have a VirtualBox process hanging around which I tried to kill (KILL/ABORT) but without success. The parent pid is 1 (init).
top shows the process as D which is documented as "uninterruptible sleep".
strace shows up nothing.
How can I get rid of this? It prevents me from unloading the VirtualBox kernel driver to load a newer one.
Simple answer: you cannot.
Longer answer: the uninterruptable sleep means the process will not be woken up by signals. It can be only woken up by what it's waiting for. When I get such situations eg. with CD-ROM, I usually reset the computer by using suspend-to-disk and resuming.