| Somewhat misleading but whatever. I doubt that user stack space
| needs special allocation. I always thought that that's one of VM's
| responsibilities. I think it should be enough just to tell VM
| where stack should be and VM will provide anon memory when it
| needed(faulted). VM should check process' limits though.
| Well, I might be wrong and I haven't looked at uvm code enough yet.

The stack needs to be explicitly mapped in as a ZFOD mapping.  Look
at vmcmd_map_zero().

Eduardo