Yes, the big issue is exactly what VirtualBox screws up in this matter,
how to detect it, and how to work around it.
It's pretty clear it's a VirtualBox f*ckup at this point, but the
failure mechanism isn't at all obvious and so far the workaround is elusive.
I'm strongly suspect this is a VirtualBox tcache management failure, but
that doesn't help the situation without knowing how it happens.
-hpa
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