Booting with SYSLINUX on Loopback Device: Kernel Panic - Where to Start?

[张云]

First your must know exactly how linux boot (not at source code level).

Most recent linux distributions boot as

        grub —> kernel —> initramfs’ /init executable

All the userspace affair is started by initramfs’ /init. Kernel no longer join the boot process.

From you description, I think you were blocked by the initramfs concept. Initramfs is the first root filesystem and reside in memeory. 
It’s loaded by grub, and the kernel automatically mount it, execute the /init. The /init executable can do some extra initialisation 
and switch to the real root filesystem on disk.
for detail /Documentaion/filesystems/ramfs-rootfs-initramfs

Hope that would be useful to your.  

> On Mar 5, 2016, at 2:38 AM, Patrick <plafratt at gmail.com> wrote:
> 
> Hello,
> 
> I was able to install SYSLINUX on a disk image and get the kernel I built to start booting Linux with QEMU pointing to a loopback device associated with the disk image. However, at some point far into the boot process, I get a kernel panic. I can't read the beginning of the error messages that the kernel prints, because the errors run off the screen.
> 
> I copied the bzImage onto the disk image, and I'm not sure where to go from there. Is the next step to build the initrd image? I don't yet know how to get the kernel to mount a device so it can find the root file system.
> 
> Any help is appreciated.
> 
> Patrick
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