Ubuntu系统强制按电源键关机之后再重新启动失败，提示：
Killed
Mount: mounting /dev on /root/dev failed :no such file or directory
Mount: mounting /sys on /root/sys failed :no such file or directory
Mount: mounting /proc on /root/proc failed :no such file or directory
Target filesystem doesn’t have requested /sbin/init
No init found. Try passing init=bootarg
BusyBox v1.15.3 (Ubuntu 1:1.15.3-ubuntu5)built-in shell (ash)
Enter ‘help’ for a list of built-in commands.
(initramfs)_