hand over arg/env pages on exec (was: Deadlock on fragmented memory?)

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

vfork childs aside, the kernel could just zero out what it wouldn't copy; 
no new interface needed.
However, how do you deal with the case that the strings are scattered around 
the dying process' address space?
Or is it intentional to have a new exec interface only to be used when the 
caller knows the arguments are contigous?