Re: Request For Help - Embedded x86, Kernel 2.6.33 boots, Mounts JFFS2 rootfs, Stops at init

From: Graeme Russ
Date: Wed Apr 28 2010 - 19:14:32 EST


On Thu, Apr 29, 2010 at 1:37 AM, Alexander Clouter <alex@xxxxxxxxxxxxx> wrote:
> Graeme Russ <graeme.russ@xxxxxxxxx> wrote:
>>
>> I've been working for a while now getting the x86 U-Boot port up to speed
>> to boot a linux kernel
>>
> ...ewww x86.

Yeah, nothing like a challange ;)

>
>> [snipped]
>>
>> [ 1.911896] Write protecting the kernel read-only data: 596k
>> [ 1.915842] kernel_execve(/sbin/init)
>>
>> (I've added a printk in kernel_execve() which gives me the last line)
>>
>> I initially had hot-plug support compiled into the kernel and was getting
>> a lot of kernel_execve(/sbin/hotplug) messages as well (plus a udev:
>> starting version 151 message which appear 100+ seconds and the above
>> messages), but I have since removed that and used mknod to create
>> /dev/ttyS0 directly
>>
>> I have also tried the following test script:
>>
>> #!/bin/bash
>> stty -F /dev/ttyS0 115200
>> cat hello > /dev/ttyS0
>>
>> but still no luck
>>
>> Does anyone have any advise on how I can debug this problem?
>>
> What does you /dev directory look like? You need to have at least the
> following:
> ----
> mknod console c 5 1
> mknod null c 1 3
> mknod ttyS0 c 4 64
> ----
>

tick, tick, tick

A little further background (should have included this last night but it
was late and I thought the problem must be trivial)...

I had originally mounted this root fs using NFS with (very) limited
success. After mounting and performing a few NFS requests (observed using
wireshark) the NFS activity would simply stop with 'server not responding'
messages. I turned on debugging in the 8139too and NFS drivers. With
debugging output enabled I was still getting 'server not responding'
messages, but (eventually) the boot sequence would continue. This even
resulted in logs in /var/log of the NFS share for the device (filled with
raw network packet data).

But no console...

What if I init with the following:

#!/bin/bash
echo hello > /hello.txt

and then rebooted and checked the root fs in U-Boot? How long will it
take for hello.txt to be flushed? Can I force the flush?

Regards,

Graeme
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