Comment 3 for bug 817304

about the hanged process, it seems to be " /usr/share/debconf/frontend /var/lib/dpkg/info/lava-dashboard.postinst configure 0.6-0ubuntu0~lava1"

16:09:45 liuyq:~$ pstree -ap 2119
bash,2119
  └─apt-get,2330 install mumble
      └─dpkg,2335 --status-fd 31 --configure man-db lava-server lava-dashboard
          └─frontend,3815 -w /usr/share/debconf/frontend /var/lib/dpkg/info/lava-dashboard.postinst configure 0.6-0ubuntu0~lava1
              └─(lava-dashboard.,3886)
16:09:49 liuyq:~$ sudo kill -9 3815

but when execute "lava-dashboard.postinst", it will do as follows:
16:25:22 liuyq:~$ sudo sh -x /var/lib/dpkg/info/lava-dashboard.postinst configure 0.6-0ubuntu0~lava1
+ set -e
+ '[' -f /usr/share/debconf/confmodule ']'
+ . /usr/share/debconf/confmodule
++ '[' '!' '' ']'
++ PERL_DL_NONLAZY=1
++ export PERL_DL_NONLAZY
++ '[' '' ']'
++ exec /usr/share/debconf/frontend /var/lib/dpkg/info/lava-dashboard.postinst configure 0.6-0ubuntu0~lava1

it will call "/usr/share/debconf/frontend /var/lib/dpkg/info/lava-dashboard.postinst" again, this cause an infinite loop.

may be it's either a bug of "/var/lib/dpkg/info/lava-dashboard.postinst" or a bug of "/usr/share/perl5/Debconf/ConfModule.pm"