This may be a reason, because I run VirtulBox (latest 5.0.10) with Ubuntu 15.04 (guest OS) on my laptop with Windows 7 x64 (host OS). Here I'm building a docker image - compile perl 5.22, based on Ubuntu 14.04 image. I tried to build the same image (same Dockerfile) on workstation with Ubuntu 14.04 host (without VirtualBox) - issue is not observed. -- Sergey