In arch/um/os/start_up.c, function start_ptraced_child() does:
pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL);
where sp points into a newly- mmap()ed page. Instead, why not
avoid the mmap() entirely via:
pid = clone(ptrace_child, NULL, SIGCHLD, NULL);
Because the flags to clone() do not contain CLONE_VM, then the clone()
is equivalent to a fork() with respect to address space. The child does not
share VM with the parent, and using the same addresses for the stack
causes no overwrites. Perhaps the Dcache efficiency is slightly
less, but much less costly than mmap() and the eventual munmap().
--
John Reiser, [EMAIL PROTECTED]
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