prison_ip_restrict() is called in loop FOREACH_PRISON_DESCENDANT_LOCKED. While under low memory, it is still possible that subsequent round prison_ip_restrict() succeed and redo_ip[4,6] flip over from true to false, thus leave some prisons's IPv[4,6] addresses unrestricted.
Fixes: 8bce8d28abe6 jail: Avoid multipurpose return value of function prison_ip_restrict()