[Buildroot] Problem with NFS boot

[Buildroot] Problem with NFS boot

[Santhosh Ramani]

Hello,

I'm using buildroot to create my rootfs for AM335x device and have been
able to successfully boot using an SD Card. However, when I try to use NFS
and boot it always gives me the following

[    3.628326] VFS: Mounted root (nfs filesystem) on device 0:14.
[    3.635009] Freeing init memory: 228K
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
Populating /dev using udev: /etc/init.d/S10udev: line 45: can't create
/proc/sys/kernel/hotplug: nonexistent directory
cannot open /dev/null
done
Starting system message bus: done
Starting network...
ip: RTNETLINK answers: File exists
can't open /dev/ttyO0: No such file or directory
can't open /dev/ttyO0: No such file or directory
can't open /dev/ttyO0: No such file or directory
can't open /dev/ttyO0: No such file or directory
can't open /dev/ttyO0: No such file or directory
can't open /dev/ttyO0: No such file or directory
can't open /dev/ttyO0: No such file or directory

I must clarify that I am using the Linux kernel not built by Buildroot but
by manually building from the TI SDK. So the only thing I use from
Buildroot is the rootfs..it works fine when I untar it on my sd card, but
doesn't seems to work over the network  Also I've selected udev option in
buildroot.

Thanks for your replies.
Regards

Ssanthosh

-- 
Greater the Difficulty....Sweeter is the Victory
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[Buildroot] Problem with NFS boot

[Stephan Hoffmann]

Am 01.12.2012 17:38, schrieb Santhosh Ramani:
> I must clarify that I am using the Linux kernel not built by Buildroot
> but by manually building from the TI SDK. So the only thing I use from
> Buildroot is the rootfs..it works fine when I untar it on my sd card,
> but doesn't seems to work over the network  Also I've selected udev
> option in buildroot.
How did you create the directory that you export via nfs? You have to
untar the target root created by buildroot using sudo.

Kind regards

Stephan

-- 
reLinux     -    Stephan Hoffmann
Am Schmidtgrund 124    50765 K?ln
Tel. +49.221.95595-19    Fax: -64
www.reLinux.de     sho at reLinux.de

[Buildroot] Problem with NFS boot

[Santhosh Ramani]

Hello Stephan,

Thank you for your reply, yes I did untar the rootfs.tar.bz2 into the
folder that is exported as NFS using sudo.

Note:
Linux kernel from TI SDK + buildroot rootfs = no nfs (only SD Card)
Linux kernle from buildroot + buildroot rootfs = everything works fine.

I actually have a script that performs a distclean on the Linux folder and
then tars and copies the linux kernel into the dl folder for buildroot. And
I have set it up so that buildroot uses this custom kernel.

However there are times when I make minor modifications to the Kernel code
and then try it out in which case it fails. That's what I'm trying to fix.

Please do let me know if I can provide more information.
Thank you
Regards

Santhosh


-- 
Greater the Difficulty....Sweeter is the Victory
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[Buildroot] Problem with NFS boot

[Stephan Hoffmann]

Am 02.12.2012 02:51, schrieb Santhosh Ramani:
> Hello Stephan,
>
> Thank you for your reply, yes I did untar the rootfs.tar.bz2 into the
> folder that is exported as NFS using sudo. 
>
> Note:
> Linux kernel from TI SDK + buildroot rootfs = no nfs (only SD Card)
> Linux kernle from buildroot + buildroot rootfs = everything works fine.
Hello Santhosh,

reading this I suggest double checking the kernel versions and
configurations. I assume the rootfs' are the same, aren't they?


>
> I actually have a script that performs a distclean on the Linux folder
> and then tars and copies the linux kernel into the dl folder for
> buildroot. And I have set it up so that buildroot uses this custom kernel.
>
> However there are times when I make minor modifications to the Kernel
> code and then try it out in which case it fails. That's what I'm
> trying to fix.
Why don't you build the modified kernel with buildroot?
>
> Please do let me know if I can provide more information.
> Thank you
> Regards
>
> Santhosh
>
>
> -- 
> Greater the Difficulty....Sweeter is the Victory
;-)

Good luck

Stephan
>
>
> _______________________________________________
> buildroot mailing list
> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot


-- 
reLinux     -    Stephan Hoffmann
Am Schmidtgrund 124    50765 K?ln
Tel. +49.221.95595-19    Fax: -64
www.reLinux.de     sho at reLinux.de


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[Buildroot] Problem with NFS boot

[Thomas Petazzoni]

Dear Santhosh Ramani,

On Sat, 1 Dec 2012 19:51:37 -0600, Santhosh Ramani wrote:

> Thank you for your reply, yes I did untar the rootfs.tar.bz2 into the
> folder that is exported as NFS using sudo.
> 
> Note:
> Linux kernel from TI SDK + buildroot rootfs = no nfs (only SD Card)
> Linux kernle from buildroot + buildroot rootfs = everything works fine.

What /dev management solution are you using? Static? Dynamic?

If you're using one of the dynamic solutions (devtmpfs, mdev or udev),
make sure that your kernel is built with CONFIG_DEVTMPFS and
CONFIG_DEVTMPFS_MOUNT. When the kernel is built by Buildroot, Buildroot
automatically enables those options. When your kernel is built
manually, you have to make sure those options are enabled.

Best regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

[Buildroot] Problem with NFS boot

[Santhosh Ramani]

Hello Stephen,

Thanks for your reply again, yes the rootfs are the same and the Linux
kernel is also the same since I tar the kernel and then buildroot uses that
as my custom kernel.

The only reason to not use the buildroot system to create the kernel image
is that it builds clean and this increases the build times. I would like to
get to a point where I can fix the rootfs temporarily, get the linux kernel
cleaned up and then go to the rootfs fixup.

Any thoughts on this one? In either case, the buildroot process should
create an identical kernel as compared to the TI -sdk should it not - if
the configurations are the same. Which I'm sure they are...

Thank you
Regards

Santhosh
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[Buildroot] Problem with NFS boot

[Stephan Hoffmann]

Am 03.12.2012 21:28, schrieb Santhosh Ramani:
> Any thoughts on this one? In either case, the buildroot process should
> create an identical kernel as compared to the TI -sdk should it not -
> if the configurations are the same. Which I'm sure they are...
Hi Santosh,

did you act upon Thomas' mail about 12 hours ago?

Another thought: Why not create a working kernel with buildroot and use
this binary for further work without rebuilding it each time?

Good luck

Stephan

-- 
reLinux     -    Stephan Hoffmann
Am Schmidtgrund 124    50765 K?ln
Tel. +49.221.95595-19    Fax: -64
www.reLinux.de     sho at reLinux.de

[Buildroot] Problem with NFS boot

[Santhosh Ramani]

Hello Stephen, Thomas,

Yes the solution mentioned by Thomas fixed it. Once I enabled devtmpfs...it
mounts it first and the udev starts. Thank you sooo very much.

[    3.581359] VFS: Mounted root (nfs filesystem) on device 0:15.
[    3.588256] devtmpfs: mounted
[    3.591857] Freeing init memory: 228K
Starting logging: OK
Populating /dev using udev: [    4.088989] udevd[712]: starting version 182
done
Initializing random number generator... done.

This is really helpful. thank you
Regards

Santhosh
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