Rottserver UTCB Bug?

Hi!
I was wondering why Sigma0/1 and Roottask share the same UTCB? Is this
on purpose?

I'm talking about:
http://l4hq.org/viewcvs/pistachio/kernel/src/api/v4/thread.cc?revision=1
.65.4.15

In init_root_servers() the function create_root_server() is called with
ROOT_UTCB_START for any rootserver. Thus every rootserver uses the same
TCRs - e. g. message registers. Wouldn't it be possible that one
rootserver overwrites values in the message registers, which another
rootserver still needs? E. g. sigma0 gets interrupted during pagefault
handling and roottask sends some IPC in between.

Best,

Martin.