(In reply to comment #9)
> Created attachment 82616 [details] [review] [review]
> possible fix
> 
> This patch fixes the issue for me.

The patch itself is correct, but the problem is it shouldn't be necessary!

When the increment is incorrect we should just make allot of small page
directory updates instead of one big update, not as efficient but should work
also...

Could you try to setting the increment to something like 0xffffffff and so
disable the accumulation of updates and see if that still doesn't work?