Bug#435241: XEN: "4gb seg fixup" in Dom0 reproducible with xen-tools

[<galahad_debian@inode.at>]

Package: linux-image-2.6.18-4-xen-686
Version: 2.6.18.dfsg.1-12etch2
Severity: important

When using XEN in Debian I get repeatably lots of pages containing "4gb
seg fixup"-errors (details below) although i'm using libc6-xen and retried
with /lib/tls removed as well.
I was able to reproduce it every time and on different machines. Without
starting any DomU enter the following command in Dom0 to create a new DomU
with bootstraping (package xen-tools):

    xen-create-image --hostname testetch2 --debootstrap --dist etch

I already assigned this bug report to "xen-utils" where I was hinted that
this is not an issue with xen-tools
(http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=431041).


ERROR-DESCRIPTION:

The errors apear shortly after this line appears...

    Installing your system with debootstrap mirror
http://debian.inode.at/debian/

... and won't stop until the next line ("Done") from xen-tools
appears.Errors (400+ lines) like this clutter up the the console:

    printk: 148430 messages suppressed.
    4gb seg fixup, process apt-get (pid 12238), cs:ip 73:b7d09ccc

And can be found in the syslog too:

    Jun 28 17:33:32 debian kernel: printk: 148430 messages suppressed.
    Jun 28 17:33:32 debian kernel: 4gb seg fixup, process apt-get (pid
12238), cs:ip 73:b7d09ccc

They vary in the numbers and the process; other processes besides apt-get
are e.g.:
mount, base-files.post, dpkg, tar, update-alternat, tar, frontend, locale,
dpkg-deb, dpkg-divert, preinst, ls
... and much more.


USED CONFIGURATION:

I am using Debian GNU/Linux 4.0 "etch" with the following components (from
dpkg -l, value in brackets is column "version"):

linux-image-2.6.18-4-xen-686 (2.6.18.dfsg.1-12etch2)
libc6-xen (2.3.6.ds1-13)
linux-modules-2.6.18-4-xen-686 (2.6.18.dfsg.1-12etch2)
xen-hypervisor-3.0.3-1-i386-pae (3.0.3-0-2)
xen-linux-system-2.6.18-4-xen-686 (2.6.18.dfsg.1-12etch2)
xen-utils-3.0.3-1 (3.0.3-0-2)
xen-tools (2.8-2)
xen-utils-common (3.0.3-0-2)

Both machines have "pae" in their /proc/cpuinfo.


FURTHER INFOS:

Another interesting fact is that the same approach in "Ubuntu 7.04 Server"
(which is a Debian-derivate after all) works fine. Maybe it's possible to
narrow the bug hunt by looking what's different there? I give the
information about the Ubuntu packages as well, probably they will be
useful. If not feel free to ignore the information:
The xen-tools version in Ubuntu is 3.0.3-0ubuntu1 and libc6-xen is
2.5-0ubuntu14.


Regards,
Andreas