pxelinux.0 3.63 hangs with boot ROMs from kvm-pxe

Binary package hint: etherboot

When trying to setup KVM virtual machines via PXE boot I came across this issue:

Booting via PXE works until the kernel should be loaded. I see in the tftpd logfile that pxelinux.0 is loaded, that the config file from pxelinux.cfg is loaded and additional files from that:

Apr 17 23:26:18 raman atftpd[11884]: Serving pxelinux.0 to 192.168.48.85:2001
Apr 17 23:26:18 raman atftpd[11884]: Serving pxelinux.cfg/01-00-50-56-00-00-1b to 192.168.48.85:57089
Apr 17 23:26:18 raman atftpd[11884]: Serving knoppix62/german.kbd to 192.168.48.85:57090
Apr 17 23:26:18 raman atftpd[11884]: Serving knoppix62/boot.msg to 192.168.48.85:57091
Apr 17 23:26:18 raman atftpd[11884]: Serving knoppix62/logo.16 to 192.168.48.85:57092

But after that the virtual machine only shows the boot: prompt (and the kvm process on the host uses 100% CPU).

This happens with pxelinux.0 from lucid's syslinux package:

# strings /usr/lib/syslinux/pxelinux.0 |grep PXELINUX
PXELINUX 3.63 Debian-2008-07-15

If I replace pxelinux.0 with a newer file:

# strings ./pxelinux.0 |grep PXELINUX
PXELINUX 3.83 Debian-2009-10-06

everything boots as expected.

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: kvm-pxe 5.4.4-1ubuntu1
ProcVersionSignature: Ubuntu 2.6.32-21.31-generic 2.6.32.11+drm33.2
Uname: Linux 2.6.32-21-generic x86_64
Architecture: amd64
Date: Sat Apr 17 23:29:40 2010
Dependencies:

PackageArchitecture: all
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: etherboot