Unmount busy filesystem and find process linux

sudo umount /mntumount: /mnt: device is busy.
        (In some cases useful info about processes that use
         the device is found by lsof(8) or fuser(1))

lsof /mntCOMMAND   PID     USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
bash            19005       user  cwd DIR   8,17        4096         2           /mnt


sudo kill -9 19005