/var/log/messages
Jul 16 07:22:52 kernel: vm_thread_new: kstack allocation failed
Jul 16 07:30:00 kernel: vm_thread_new: kstack allocation failed
Jul 16 07:31:54 last message repeated 3 times
Jul 16 07:32:54 kernel: sonewconn: pcb 0xc5ed88dc: pru_attach() failed

/var/log/cron
Jul 16 07:01:00 /usr/sbin/cron[866]: (root) CMD (periodic daily)
Jul 16 07:30:00 /usr/sbin/cron[763]: (CRON) error (can’t fork)
Jul 16 07:31:00 /usr/sbin/cron[763]: (CRON) error (can’t fork)
Jul 16 07:31:01 /usr/sbin/cron[957]: (CRON) error (can’t vfork)