1) created on host machines with greater than 4GB of memory, and
   2) the active guest task at crash-time had been assigned a page
      directory page (cr3) with a machine address greater than 4GB.

  If both of the above apply, the crash session would fail with one of
  two error messages, either "crash: cannot read/find cr3 page", or
  "crash: cannot create xen pfn-to-mfn mapping".  (anderson@redhat.com)

- Fix for the "kmem -p [page-struct-address]" command construct, which
  would cause a segmentation violation when run on SPARSEMEM kernels.
  (anderson@redhat.com)

- Added a new "struct -u" option, which indicates that the subsequent
  address argument is a user virtual address in the current context.
  This option could be used, for example, if a known kernel data
  structure exists at user virtual address in the current context,
  or if the debuginfo data of a user program were loaded into the
  crash session via the gdb "add-symbol-file" command.
  (anderson@redhat.com)

- Added new "rd -f" and "struct -f" options, which indicate that the
  subsequent address argument is a dumpfile file offset.  These options
  could be used, for example, to print a known kernel data structure
  that exists in the dumpfile header, or to simply dump data directly
  from the dumpfile.  (anderson@redhat.com)

- Cosmetic fix to prevent double-printing of "kmem -p" and "kmem -v"
  headers when they are passed multiple address arguments.
  (anderson@redhat.com)
 

Download from: http://people.redhat.com/anderson