Kernel panic when using NFS!
 

Hello,

I've installed a NFS server on my host pc and run my embedded linux board using NFS as rootfs. I've loaded the kernel successfully but it will hang (kernel panic) because the NFS server returned an error.

The NFS server is verified working by mounting it using this command "mount -t nfs <server ip>:/home/nfsroot /mnt"

This is the kernel parameter used "console=ttyAM root=/dev/nfs ip=192.168.2.181:192.168.2.103:192.168.2.1:255.255.255.0 nfsroot=:192.168.2.103:/home/nfsroot"

Here's the message log:
...
...
ep93xx-rtc ep93xx-rtc: setting system clock to 1970-01-01 00:01:34 UTC(94)
IP-Config:
Complete:
device=eth0, addr=192.168.2.181, mask=255.255.255.0, gw=192.168.2.1,
host=192.168.2.181, domain=, nis-domain=(none),
bootserver=192.168.2.103, rootserver=192.168.2.103, rootpath=
Looking up port of RPC 100003/2 on 192.168.2.103
scsi 0:0:0:0: Direct-Access SanDisk Cruzer Micro 0.1 PQ: 0 ANSI: 2
sd 0:0:0:0: [sda] 4001760 512-byte hardware sectors (2049 MB)
sd 0:0:0:0: [sda] Write Protect is off
sd 0:0:0:0: [sda] Assuming drive cache: write through
sd 0:0:0:0: [sda] 4001760 512-byte hardware sectors (2049 MB)
sd 0:0:0:0: [sda] Write Protect is off
sd 0:0:0:0: [sda] Assuming drive cache: write through
sda:sda1
sd 0:0:0:0: [sda] Attached SCSI removable disk
rpcbind: server 192.168.2.103 not responding, timed out
Root-NFS: Unable to get nfsd port number from server, using default
Looking up port of RPC 100005/1 on 192.168.2.103
Root-NFS: Server returned error -13 while mounting /tftpboot/:192.168.2.103:/home/nfsroot
VFS: Unable to mount root fs via NFS, trying floppy.
VFS: Cannot open root device "nfs" or unknown-block(2,0)
Please append a correct "root=" boot option; here are the available partitions:
1f00 16384 mtdblock0 (driver?)
0800 2000880 sda driver:sd
0801 1999749 sda1
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(2,0)

Also, the connection between the two devices is working. I can ping from the host pc to client and ping from client using RedBoot bootloader to host pc.

What could be the problem? Hope to here response from this forum.

Thanks.

It has been a while since I tried this, but the article below helped me a lot when I was playing with it. I don't use Arch, but it should be a similar setup on any distribution. I hope it helps in some way.

http://wiki.archlinux.org/index.php/..._boot_NFS_root

That '/tftpboot/:192.168.2.103' seems a little fishy to me. Also, I believe that error (-13) means permission denied. Could you post up your '/etc/exports'?

For development purposes, just put '/home/nfsroot *(rw,no_root_squash,no_all_squash)' in your exports file.

I suggest first booting over NFS with an isolated switch (no gateway, etc). You can move over to your regular network once you have that working.