double fault -> PAGE_KERNEL flagged memory

[Frank Ch. Eigler]

zanussi wrote:

> [...]  What would cause a double fault would be if the vmalloc_fault
> tried logging before the page table was updated, which would cause
> the same vmalloc fault.

Then this is analogous to the problem of calling printk from within an
inconveniently placed kprobe.  What can we do to eliminate this
vulnerability?  Can we somehow arrange to "fault in" all probe-related
kernel-space vmalloc areas into new process' address spaces, so we don't
encounter this unintentional and undesirable reentrancy?

- FChE