Install vmlinux on Ubunut

Reference: http://superuser.com/questions/62575/where-is-vmlinux-on-my-ubuntu-installation

Why I need install vmlinux ? Because i will use `crash` tool to debug kernel :D   

you can step by step to install vmlinux on below:

1. apt install vmlinux 

echo "deb http://ddebs.ubuntu.com $(lsb_release -cs)-updates main restricted universe multiverse
deb http://ddebs.ubuntu.com $(lsb_release -cs)-security main restricted universe multiverse
deb http://ddebs.ubuntu.com $(lsb_release -cs)-proposed main restricted universe multiverse" | \
sudo tee -a /etc/apt/sources.list.d/ddebs.list

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 428D7C01

sudo apt-get update
sudo apt-get install linux-image-$(uname -r)-dbgsym

2. find out vmlinux :

/usr/lib/debug/boot/vmlinux-$(uname -r)