Buildroot - built a file system, how to login? boot hangs

Question

Can someone help me to understand how I need to configure buildroot, so that I will be able to successfully boot my own file system and login to it ?

I have a (seemingly) working kernel, and now I created my own file system (didn't change any settings in build root really, except set console to ttyAMA0), but the boot process just seems to hang without any problems to this:

....
[    3.130000] VFS: Mounted root (ext3 filesystem) on device 179:2.
[    3.140000] Freeing init memory: 144K
Starting logging: OK
Starting network...
ip: RTNETLINK answers: Operation not permitted
ip: SIOCSIFFLAGS: Permission denied

Whole boot log is visible here: http://paste.ubuntu.com/1364407/

I understand that /etc/inittab controls the boot process, the contents looks like this:

# Startup the system
null::sysinit:/bin/mount -t proc proc /proc
null::sysinit:/bin/mount -o remount,rw / # REMOUNT_ROOTFS_RW
null::sysinit:/bin/mkdir -p /dev/pts
null::sysinit:/bin/mkdir -p /dev/shm
null::sysinit:/bin/mount -a
null::sysinit:/bin/hostname -F /etc/hostname
# now run any rc scripts
::sysinit:/etc/init.d/rcS

# Put a getty on the sttyAMA0::respawn:/sbin/getty -L ttyAMA0 115200 vt100 # GENERIC_SERIAL

# Stuff to do for the 3-finger salute
::ctrlaltdel:/sbin/reboot

# Stuff to do before rebooting
null::shutdown:/etc/init.d/rcK
null::shutdown:/bin/umount -a -r
null::shutdown:/sbin/swapoff -a

Any advice on what is wrong in my configuration ? Any tips on where I could get a good overview of "the usual necessary configurations" needed when creating my own linux system ?

Answer 1

This problem was raised by the submitter on the Buildroot mailing list. The solution was that the submitter was using Buildroot the contents of output/target directory directly as its root filesystem, even though the Buildroot documentation explicitly tells not to do so. This is because Buildroot does not run as root, and therefore cannot create device files or adjust permissions/ownerships properly in output/target. These steps are done when creating the root filesystem images, thanks to a magic tool called fakeroot.

Therefore, if someone wants the root filesystem to extract on a SD card partition or something like that, one should ask Buildroot to generate a tar image, and then extract it as root in the SD card partition.

Since this problem was quite common, we have now added a file in output/target called THIS_IS_NOT_YOUR_ROOT_FILESYTEM which contains details about this issue. See http://git.buildroot.net/buildroot/commit/?id=9226a9907c4eb0fffab777f50e88b74aa14d1737.