Automount devtmpfs at /dev, after the kernel mounted the rootfs


Linux Kernel Configuration
└─>Device Drivers
└─>Generic Driver Options
└─>Automount devtmpfs at /dev, after the kernel mounted the rootfs
In linux kernel since version 2.6.32 (release Date: 2009-12-02)  
This will instruct the kernel to automatically mount the
devtmpfs filesystem at /dev, directly after the kernel has
mounted the root filesystem. The behavior can be overridden
with the commandline parameter: devtmpfs.mount=0|1.
This option does not affect initramfs based booting, here
the devtmpfs filesystem always needs to be mounted manually
after the rootfs is mounted.
With this option enabled, it allows to bring up a system in
rescue mode with init=/bin/sh, even when the /dev directory
on the rootfs is completely empty.