Help:about boot from PXE

grep_one

hi all,
im trying to setup a diskless environnement with Fedora.
I use etherboot (as a bootable CDROM) to load linux kernel via PXE.
I have a dhcp, nfs and a tftp server working properly.
I have rebuild a 2.6.9-1.667_FC3 fedora kernel
I have rebuild a kernel (as an rpm, or via make bzImage), with the
NFSROOT option, to allow / mounting via NFS
pxelinux.0 boot normaly, load the kernel and the initrd, but when the
kernel try to moun the / partition, i obtain a kernel panic message:


VFS: Cannont open root device "nfs" or unknow-block(0,255)
Please append a correct "root=" boot option
Kernel Panic - not syncing : VFS: Unable to mount root fs on
unknow-block(0,255)


After that, i have tried many other options in the linux kernel (using
devfs instead udev, yes i know it's obsolete ), and some other tips i
found but no one worked. Note that on the NFS Server i don't see any
packet using the NFS protocol.
Is there some special configuration with Fedora kernels and nfsroot option ?


Thanks for your suggest


¤ Here is my pxelinux.cfg/default file :
kernel vmlinuz
APPEND root=/dev/ram0 nfsroot=192.168.1.1:/tftpboot/192.168.1.55/root vga=normal
APPEND initrd=initrd.img devfs=nomount ramdisk_size=10000

¤ Here is the main kernel option needed (if i don't miss one!) and that
i have in my kernel:
grep -i "IP_PNP\|NFS\|RAMFS"
/DOC/PXE/root/boot/config-2.6.10-1.770_FC3nscheibl.20050525
CONFIG_INITRAMFS_SOURCE=""
CONFIG_IP_PNP=y
CONFIG_IP_PNP_DHCP=y
CONFIG_IP_PNP_BOOTP=y
CONFIG_IP_PNP_RARP=y
CONFIG_RAMFS=y
CONFIG_CRAMFS=m
CONFIG_NFS_FS=y
CONFIG_NFS_V3=y
CONFIG_NFS_V4=y
CONFIG_NFS_DIRECTIO=y
CONFIG_NFSD=m
CONFIG_NFSD_V3=y
CONFIG_NFSD_V4=y
CONFIG_NFSD_TCP=y
CONFIG_ROOT_NFS=y
CONFIG_NCPFS_NFS_NS=y


¤ Here is the config of the diskless client in my dhcp server
(/etc/dhcpd.conf):

host myclient
{
          hardware ethernet 00:14:5E:1E:00:09;
          fixed-address 192.168.1.55;
          filename "/tftpboot/pxelinux.0";
          option root-path "192.168.1.1:/tftpboot/192.168.1.55";
}


¤ And here is my nfsd config (/etc/exports):
/tftpboot/192.168.1.55 192.168.1.55(rw)

192.168.1.55 in tftpboot is a directory built manually.