[CentOS] rebuilding anaconda for centos 4.0

Wed Apr 27 19:24:18 UTC 2005
David Thompson <thomas at cs.wisc.edu>

David Thompson wrote:
>Hi all:
>I'm trying to rebuild the anaconda installer for Centos 4.0 (i386) to add some
>RPMs and do some other things, and I've run into a problem.  I've done lots of
>anaconda rebuilds for Tao Linux 1.0, and I'm bringing those bits forward into 
>Centos 4.0.  The all-knowing web hasn't turned up anything useful.  It looks 
>like the PXE-loaded kernel unpacked and mounted the initrd OK, but then things
>went awry (quickly).  Anyone seen this on a PXE boot of an anaconda build?
>RAMDISK: Compressed image found at block 0
>VFS: Mounted root (ext2 filesystem).
>VFS: Cannot open root device "<NULL>" or unknown-block(3,2)
>Please append a correct "root=" boot option
>Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(3,2)

Well, since no one replied to this I'll follow up my own post.

It turns out that the 2.6.9-5.0.3.EL series of kernels has a bug in loop back 
mounting file systems:


(the bug is filed against fc3 but affects the original centos 4.0 kernels as 
well.)  The bug prevents the initrd.img in anaconda from being populated, and 
everything goes kaplooey as soon as the PXE boot tries to do anything with 
it's initrd.  It would also affect rebuilt ISO images.

The fix is to upgrade the host running buildinstall to a 2.6.9-5.0.5.EL 
kernel, which has a fix for bug 105595.  Then everything works just fine.

Dave Thompson  ( thomas(at)cs(dot)wisc(dot)edu )

Associate Researcher                  Department of Computer Science
University of Wisconsin-Madison       http://www.cs.wisc.edu/(twiddle)thomas
1210 West Dayton Street
Madison, WI 53706-1685