Mine

Layer 1
	fork();
Layer 3
	/usr/src/servers/pm/main.c	-->	get_work()	-->	do_fork();
	/usr/src/servers/pm/forkexit.c	-->	do_fork()	-->	sys_fork();
Layer 4
	/usr/src/kernel/system.c	-->	system_task()	-->	do_fork();
	/usr/src/kernel/system/do_fork.c	/* does a fucking kernel level fork */

Layer 3
	/usr/src/servers/pm/forkexit.c	-->	returns at sys_fork();