[fedora-arm] Custom compiled kernel hangs on spawning /sbin/init

[Alex Villací­s Lasso]

El 15/03/12 12:49, Alex Villací­s Lasso escribió:
> I am having trouble booting a Fedora-15 ARM userspace on a pico-SAM9G45 with a custom-compiled kernel.
>
> http://arm.mini-box.com/index.php?title=Main_Page
>
> I am able to cross-compile a vendor-supplied kernel source with support for fbcon to see what I am doing. The boot microSD has a FAT boot partition with an uImage and a ext3 partition with Fedora 15. The ext3 filesystem previously booted correctly on a 
> qemu-system-arm emulation with -M versatilepb . On the LCD I see the penguin logo and the ordinary kernel messages, but stops right after "Freeing init memory: 140K" Then I have no output from userspace.
>
> I can plug in an USB keyboard and I see kernel messages. I can even scroll up and down on the LCD output using the USB kernel. That shows that the kernel is not dead. So I suspect I am having trouble running /sbin/init .However, I see no output that 
> could point me to what exactly is wrong. Nothing like a SIGSEGV or an incompatibility message. The root filesystem is being mounted, because I see "VFS: Mounted root (ext3 filesystem) on device 179:2"
>
> I have tried adding initcall_debug to the kernel command line but it has no effect in my case.
>
> The kernel is being booted without an initrd. At first I thought it could be the issue, but I tried replicating the problem on a x86 PC (removing the initrd directive from GRUB and adding root=/dev/sdb2) and the system does boot to completion.
>
> I also though maybe the Fedora 15 init requires /dev/ to be populated, so I checked. It has /dev/null , /dev/console, and /dev/zero. I tried adding /dev/mmcblk0, /dev/mmcblk0p1 and /dev/mmcblk0p2 but it also has no effect.
>
> I searched in Google and found a post that described a problem similar to my own, and resolved it to an OABI/EABI incompatibility. However, the .config I used for the kernel has CONFIG_AEABI=y and CONFIG_OABI_COMPAT=y , just the same as 
> config-2.6.41.6-1.fc15.armv5tel being used to compare.
>
> The config file used to compile the kernel is attached.
I tried compiling the following program statically in the qemu-system-arm emulation:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main(void)
{
     FILE * f;

     f = fopen("/tmp/test-static.txt", "wt");
     if (f != NULL) {
         fputs("Esto es una prueba\n", f);
         fclose(f);
     }
     sync();

     puts("Hola mundo");
     fflush(stdout);

     return 0;
}

I then pointed the init parameter to the resulting executable. When booting, I do *not* see the string being output with puts(), but after examining the filesystem, I do see the test file /tmp/test-static.txt with the expected content. So somehow the 
program does not have access to the console, but does have access to the filesystem. I suppose the initrd has the same issue.