xen.xend.XendProtocol.XendError: Invalid memory / mem_kb: None

[Chris Bainbridge <chris.bainbridge@gmail.com>]

I have a domain which is rebooting. When I do xm list I sometimes get
the following error; it's probably a race condition when the domain
restarts in the middle of being queried by xm.

xen # xm list
Unexpected error: xen.xend.XendProtocol.XendError

Please report to xen-devel@lists.xensource.com
Traceback (most recent call last):
  File "/usr/sbin/xm", line 10, in ?
    main.main(sys.argv)
  File "/usr/lib/python/xen/xm/main.py", line 689, in main
    rc = cmd(args)
  File "/usr/lib/python/xen/xm/main.py", line 236, in xm_list
    info = server.xend_domain(dom)
  File "/usr/lib/python/xen/xend/XendClient.py", line 215, in xend_domain
    return self.xendGet(self.domainurl(id))
  File "/usr/lib/python/xen/xend/XendClient.py", line 150, in xendGet
    return self.client.xendGet(url, args)
  File "/usr/lib/python/xen/xend/XendProtocol.py", line 90, in xendGet
    return self.xendRequest(url, "GET", args)
  File "/usr/lib/python/xen/xend/XendProtocol.py", line 180, in xendRequest
    val = self.handleResponse(data)
  File "/usr/lib/python/xen/xend/XendProtocol.py", line 129, in handleResponse
    return self.handleException(err)
  File "/usr/lib/python/xen/xend/XendProtocol.py", line 136, in handleException
    raise err
xen.xend.XendProtocol.XendError: Invalid memory / mem_kb: None