Você tem que parar o serviço mysql. "sudo service stop"
sudo service mysql stop #or mysqld
sudo killall -9 mysql
sudo killall -9 mysqld
sudo apt-get remove --purge mysql-server mysql-client mysql-common
sudo apt-get autoremove
sudo apt-get autoclean
sudo deluser mysql
sudo rm -rf /var/lib/mysql
sudo apt-get purge mysql-server-core-5.5
sudo apt-get purge mysql-client-core-5.5
sudo rm -rf /var/log/mysql
sudo rm -rf /etc/mysql
apt-get autoclean
apt-get update
apt-get upgrade
apt-get install -f
você faz o mysql fresco instalar
OR
sudo apt-get remove --purge mysql-server mysql-client mysql-common
apt-get autoclean
apt-get update
apt-get upgrade
apt-get install -f