Fork in general is fine, although most/all CPAN modules will leak resources with fork unless they specifically say they are psuedo fork safe (have a CLONE method or use mg_dup magic). Doing a kill on a child absolutely isn't safe and never will be completely safe see ( https://rt.perl.org/rt3/Ticket/Display.html?id=88840 ). Previously doing a kill on the child the moment the parent starts the child (why would you do that in production code?) would hang the parent interp later in the parent interp's execution. I am not doing a kill anywhere. I need to, and have the child exiting voluntarily.