I think we can do better. How about a /proc/bin/yes for this? Like most /proc files, it would appear to be empty. Executing it would involve a fs/binfmt_proc.c

I think we can do better. How about a /proc/bin/yes for this? Like most /proc files, it would appear to be empty. Executing it would involve a fs/binfmt_proc.c file in the kernel source, which would be a handler for this sort of executable. That would get the job done entirely in the kernel.