If a file with bad memory addresses is configured but that file is empty (0 lines, 0 bytes), when loading it we end up returning an end pointer that is just _before_ the start of the (empty) file content. Adjust the code to make it clear what pre-condition are required to set the *list / *end pointers correctly, and explicitly set them to NULL when they are not matched. Reported by: marklmi@yahoo.com Reviewed by: kib MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D51717 (cherry picked from commit f90940ce6eb71df40538c35a65d77ad3093c679a)