从ppa中安装了virtualbox，这里没有注意，应该是有报错，载入以前的系统，报错如下：

kernel driver not installed (rc=-1908)

The VirtualBox Linux kernel driver (vboxdrv) is either not loaded or
there is a permission problem with /dev/vboxdrv. Please install
virtualbox-dkms package and load the kernel module by executing

'modprobe vboxdrv'

as root. If it is available in your distribution, you should install
the DKMS package first. This package keeps track of Linux kernel
changes and recompiles the vboxdrv kernel module if necessary.

where: suplibOsInit what: 3 VERR_VM_DRIVER_NOT_INSTALLED (-1908) - The
support driver is not installed. On linux, open returned ENOENT.

经过一番查找，需要重新安装kernel driver，方法如下

sudo apt-get install linux-headers-generic build-essential dkms
sudo apt-get remove virtualbox-dkms
sudo apt-get install virtualbox-dkms

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