Re: [patch] user-vm-unlock-2.5.31-A2

[Linus Torvalds]

On Fri, 16 Aug 2002, Ingo Molnar wrote:
> > [...] In which case we sure as heck don't want the original child to
> > modify the VM that it now shares with a subthread.
> 
> in what way is clone() utilized? if it's via any threading library then
> the fork()-ed process has its own thread state, which must be freed when
> exiting.

See this:

	process X

	fork()			
			------->	Process Y
					clone()
								----> thread Z

					exit()
					THIS MUST NOT
					WRITE TO MEMORY
					IN Z!!

Notice how the exit() in Y will never be able to write into the address 
space of X - it would only write into the address space of Z, and Z is not 
expecting that at all!

		Linus