[Buildroot] buildroot with SquashFS root file system

[Emmanuel BOUAZIZ <ebouaziz@neotion.com>]

Hi,

I'm trying to run buildroot 2011.11 on an atom based board, booting via PXE.

I've selected the SquashFS 4.x root filesystem (xz compressed), bzImage as the Kernel binary format, and
syslinux/pxelinux as the  bootloader.
In the system configuration, I checked "remount root filesystem read-write during boot"

In the kernel configuration, I checked Initial RAM filesystem and RAM disk support+XZ, and SquashFS/XZ filesystem support.

On the PXE server, I put these kernel parameters: append vga=0x305 fbcon=scrollback:4096k initrd=rootfs.squashfs

Here is what I get during the boot sequence:

(...)
RAMDISK: squashfs filesystem found at block 0
RAMDISK: Loading 14133KiB [1 disk] into ram disk.../
usb 1-7: new high speed USB device number 3 using ehci_hcd
VFS: Mounted root (squashfs filesystem) readonly on device 1:0
usb 2-2: new full speed USB device number 2 using uhci_hcd
can't open /dev/null: No such file or directory
can't open /dev/null: No such file or directory
can't open /dev/null: No such file or directory
can't open /dev/null: No such file or directory
can't open /dev/null: No such file or directory
can't open /dev/null: No such file or directory
Starting logging: OK
Starting mdev...
mdev: /sys/class: No such file or directory
Starting network...
hub 2-2:1.0: USB found
hub 2-2:1.0: 3 ports detected
ifup: can't open '/var/run/ifstate': Read-only file system
(...)

I get the exact same result if I try to use a cramfs instead of a SquashFS.

Oddly enough, it works perfectly with a cpio root filesystem, or when I integrate the root filesystem as an initramfs in
the kernel image.

I probably missed an important item, but can't figure which. Any help appreciated.

Thanks,

-- 
Emmanuel