I've seen on various Xen/amd64 setups of mine hangs like those reported in the
attached dmesg.
They seem to occur especially when dom0 is under heavy load (typically when
running climateprediction.net, if you try a dist-upgrade or an install of any
package that touches mandb, the install will hang).
It can affect pretty much any process (I've experienced it with ssh, or bash...)
I'm afraid it gets really nasty when, as in the attached output, it affects key
kernel processes such as kjournald...
Kernel: Linux 2.6.26-1-xen-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Versions of packages linux-image-2.6.26-1-xen-amd64 depends on:
ii initramfs-tools 0.92m tools for generating an initramfs
ii linux-modules-2.6.26-1-xen-am 2.6.26-12 Linux 2.6.26 modules on AMD64
linux-image-2.6.26-1-xen-amd64 recommends no packages.
Versions of packages linux-image-2.6.26-1-xen-amd64 suggests:
ii grub 0.97-47lenny1 GRand Unified Bootloader (Legacy v
pn linux-doc-2.6.26 <none> (no description available)