> You either have to copy the pages immediately (in which cases there's no COW) or you have to make all mappings to the physical page RO. One of these enhanced

> You either have to copy the pages immediately (in which cases there's no COW) or you have to make all mappings to the physical page RO. One of these enhanced fork exec calls stops the parent until the child execs. Then you don't need to touch the parent page mappings or worry about concurrency. (Although it's not ideal if the parent is threaded)