Error message for invalid initramfs cpio format?

[Ville Herva <vherva@vianova.fi>]

On Mon, Jan 23, 2006 at 09:02:16PM -0500, you [Phillip Susi] wrote:
> Ville Herva wrote:
> >PS: Speaking of debugging failing initrd init scripts; it would be nice if
> >the kernel gave an error message on wrong initrd format rather than 
> >silently
> >failing... Yes, I forgot to make the cpio with the "-H newc" option :-/.
> >  
> 
> LOL, yea, that one got me too when I was first getting back into linux a 
> few months ago and had to customize my initramfs to include dmraid to 
> recognize my hardware fakeraid raid0.  Then I discovered the mkinitramfs 
> utility which makes things much nicer ;)

Sure does, that's what I first used, too. But then I had to hack with the
init script and it seemed quicker to 

  gzip -d < /boot/initrd-2.6.15.1.img | cpio --extract --verbose --make-directories --no-absolute-filenames
  vi init 
  ...
  find . | cpio -H newc --create --verbose | gzip -9 > /boot/initrd-2.6.15.1.img

It seems do_header() in init/initramfs.c checks for the "070701" magic (that
is specific to the newc format [1]), and populate_rootfs() should then
panic() with "no cpio magic" error message, but I'm fairly sure I didn't see
an error about wrong initramfs format when booting with an initrd made with
cpio without the -H newc option. 

This is what I see:

 RAMDISK: Couldn't find valid RAM disk starting at 0.
 VFS: Cannot open root device "LABEL=/" or unknown-block(0,0)
 Please append correct "root=" boot option
 Kernel panic - not syncing: VFS: Unable to mount root fs on
 unknown-block(0,0)

seems the "no cpio magic" message is somehow lost. It would be useful.


-- v -- 

v@iki.fi



[1] "The new (SVR4) portable format, which supports file systems having more
     than 65536 i-nodes."