Reporting Bugs against Xen Project

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How to Report a Bug Against Xen

The primary location for reporting bugs against the Xen hypervisor and associated bundled tools (e.g. against xen-unstable.hg or xen-X.Y-testing.hg) is by posting to the xen-devel mailing list. However please read the following before posting.

Although a bugzilla instance does exist it is not well maintained or widely used by developers. If you really want to file a bug in bugzilla you are strongly recommended to also post to the mailing list.

If you are having a problem with Xen you should consider initially posting your issue to the xen-users mailing list, in order to rule out common configuration issues and user errors.

Before posting a bug report you are strongly encouraged to read Simon Tatham's excelent "How to Report Bugs Effectively". Please do not report Xen bugs to Simon Tatham!

Before posting you should check your favourite search engine and the list archives for both xen-users and xen-devel to see if your issue has been reported (and perhaps solved) already.

List Etiquette

xen-devel, like many open-source mailing lists, keeps to a set of conventions established in the '80s and '90s. They may seem a bit archaic these days, but breaking them is considered bad form and may cause people to skip over your bug report. There are a number of guides on the web, but some particular points that seem to show up on xen-devel are:

  • Please post in plain text (i.e. not HTML), word-wrapped to somewehere around 72 characters.
  • Please don't top-post.
  • Please start a new thread for a new bug (don't just reply to a random email from the list).
  • Please don't email bugs directly to xen developers. Keep the conversation on the list where other people (and search engines) can see it.

Bug Report Contents

The following contains suggestions of the sort of information, log files and command output you should consider providing as part of your bug report. If you are unsure then it is normally better to err on the side of providing too much information.


First and foremost please provide a clear description of the issue you are seeing. What exacly happened and what did you expect. Try to be as clear as you can, properly explaining your issue is key to us being able to help. See "How to Report Bugs Effectively" (which you have already read, right?) for examples of the sorts of bug reports which are not likely to garner a response from developers, as well as advice on how to produce a good bug report.

Also please always include the precise version of Xen you are running, i.e. a reference to the particular mercurial tree and a changeset number or the name of the distribtion which provided the packages you are using along with the version of those packages.

Where possible, please include precise steps to reproduce the issue. An issue which can be reproduced by a developer is an order of magnitude more likely to get fixed quickly.

Be sure to also include any relevant domain configuration files.

In addition there are many log files which can contain useful information:

  • /var/log/xen/xen-hotplug.log
  • /var/log/xen/qemu-dm-${DOMNAME}.log
  • /var/log/xen/console/guest-${DOMNAME}
  • Host console output (perhaps including hypervisor debug key output)
  • Guest console output (often in /var/log/xen/console)

Finally various bits of system configuration can be found in:

  • /etc/network/interfaces or /etc/sysconfig/network-scripts/*
  • /etc/xen/*
  • Network device configuration: ifconfig -a
  • Network bridging configuration: brctl show
  • Network routing configuration: route -vn
  • PCI devices: lspci -vvv
  • Xenstore contents: xenstore-ls -fp

xl specific

If you are using the xl toolstack then please consider running all xl commands with the global "-v" option e.g. xl -v create <create-options>. Also please include the output of the following commands:

  • xl info

In addition you should include the logs from /var/log/xen/xl-${DOMNAME}.log

xend specific

If you are using the xend toolstack then there are several other log files which may be of interest.

  • /var/log/xen/xend.log
  • /var/log/xend-debug.log
  • /var/log/xen/domain-builder-ng.log

Linux paravirt ops kernel issues

You should also provide the information requested on the XenParavirtOpsHelp page.