Re: Request For Help - Embedded x86, Kernel 2.6.33 boots, MountsJFFS2 rootfs, Stops at init

From: Mike Rapoport
Date: Wed Apr 28 2010 - 11:33:22 EST


Graeme Russ wrote:
Hi All,

I've been working for a while now getting the x86 U-Boot port up to speed
to boot a linux kernel

I now have a root fs (build from Linux-From-Scratch and trimmed to <15M
using qemu) but all attempts to get any serial console output past
launching of init have failed.

I have taken the root fs which successfully boots using qemu and created a
jffs2 image and flashed it onto one of the on-board flash chips. U-Boot can
successfully 'ls' the root fs

My bootags are:

root=/dev/mtdblock1 rw rootfstype=jffs2 console=ttyS0,115200

as Linux can mount the root partition:
[ 1.447819] Serial: 8250/16550 driver, 6 ports, IRQ sharing disabled

[ snip ]

[ 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?

Have you tried with init=/bin/sh?
Also, make sure you have /dev/null and /dev/console nodes.


Regards,

Graeme
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--
Sincerely yours,
Mike.
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