The argument was changed from 'proc *p' to 'process *pr' in 2010.
Index: sys/kern/kern_proc.c =================================================================== RCS file: /cvs/src/sys/kern/kern_proc.c,v retrieving revision 1.65 diff -u -p -r1.65 kern_proc.c --- sys/kern/kern_proc.c 11 Sep 2015 08:27:39 -0000 1.65 +++ sys/kern/kern_proc.c 4 Mar 2016 12:36:26 -0000 @@ -150,7 +150,7 @@ chgproccnt(uid_t uid, int diff) } /* - * Is p an inferior of parent? + * Is pr an inferior of parent? */ int inferior(struct process *pr, struct process *parent) -- Michal Mazurek