Overlay structure not present in vtypes

[samduy]

$ volatility -f mem.dump  imageinfo
Volatility Foundation Volatility Framework 2.6
INFO    : volatility.debug    : Determining profile based on KDBG search...
WARNING : volatility.debug    : Overlay structure tty_struct not present in vtypes
WARNING : volatility.debug    : Overlay structure sockaddr_un not present in vtypes
WARNING : volatility.debug    : Overlay structure net_device not present in vtypes
WARNING : volatility.debug    : Overlay structure in_ifaddr not present in vtypes
WARNING : volatility.debug    : Overlay structure tty_struct not present in vtypes
WARNING : volatility.debug    : Overlay structure sockaddr_un not present in vtypes
WARNING : volatility.debug    : Overlay structure net_device not present in vtypes
WARNING : volatility.debug    : Overlay structure in_ifaddr not present in vtypes
          Suggested Profile(s) : No suggestion (Instantiated with LinuxKali3-amd64x64)
                     AS Layer1 : FileAddressSpace (/root/project/source/uClinux-dist/mem.dump)
                      PAE type : No PAE
                           DTB : -0x1L