I just wanted to add a note here to clarify things a little bit, since
from the comments here it's all a bit muddled. There are two loosely
related things happening.

The first problem, which is fixed by setting
CONFIG_HARDENED_USERCOPY_PAGESPAN=n, is that some security enhancements
were added in kernel version 4.8 related to copying memory from
userspace. One of these hardening features was to check for copies from
userspace which cross a page boundary, and when this happens the kernel
logs an error and terminates the running task immediately by causing it
to oops. This turned out to be too aggressive for now, because the
vmwgfx module is doing these sorts of memory copies from userspace.
Therefore when CONFIG_HARDENED_USERCOPY_PAGESPAN was enabled and the
kernel booted in VMWare Fusion, Barry was getting an oops.

This triggered the second problem. There's also a patch in 4.8 which
aims to make oopsing behave more reliably by calling do_exit() with a
clean stack, and this seems to be causing some sort of problems on
VMWare Fusion when the kernel oopses. The exact nature of those problems
isn't yet clear. Fixing the problem above side steps the problems caused
by this patch as it prevents the oops from happening, however I suspect
that the problem remains.

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https://bugs.launchpad.net/bugs/1627198

Title:
  4.8.0 kernels do not complete boot process on VM

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