Emacs exited with message “X protocol error: BadPixmap”

[Joe Wells <jbw@macs.hw.ac.uk>]

I'm using Emacs 22.1.  Emacs suddenly exited (with no core dump file
to be found).  It seems it left this message on stderr:

  X protocol error: BadPixmap (invalid Pixmap parameter) on protocol request 55

A similar crash happened just a bit earlier.  Only the second time did
I see the error message.  I think the first time stderr had been
disconnected from any useful file/tty, so I'm not sure if the same
error message was there for the first crash.

It is troublesome that there is no core dump file.  I checked that
core dumps are enabled, so that is not the problem.  It seems to me
that it would be helpful if Emacs aborted to leave a core dump file in
this case.

How do I debug this if it happens again?  (Please don't tell me to
always run Emacs under gdb!)

Other details below (from a fresh Emacs invocation obviously).

Joe

P.S.  There is only one unusual thing I've done in the last day that I
can think of that seems like it could trigger a crash.  The problem
*might* have something to do with using the MPH 2B Damase font in
Ubuntu (i.e., Debian) package ttf-mph-2b-damase.  I use it like this
to substitute more readable glyphs for some characters:

  (set-fontset-font "fontset-startup" 342486 '("mark-mph" . "iso10646-1")); U+2056 “⁖” THREE DOT PUNCTUATION
  (set-fontset-font "fontset-startup" 342488 '("mark-mph" . "iso10646-1")); U+2058 “⁘” FOUR DOT PUNCTUATION
  (set-fontset-font "fontset-startup" 342489 '("mark-mph" . "iso10646-1")); U+2059 “⁙” FIVE DOT PUNCTUATION

Notes:  (1) I have been doing the same thing for more than a year for
lots of other characters from other fonts with no trouble at all.
(2) Only ASCII characters are visible on the screen at the time of the
crash.  (3) The crash happens some time _after_ the above expressions
are evaluated.  Overall, it is not clear if there is a connection.

======================================================================
In GNU Emacs 22.1.1 (i686-pc-linux-gnu, GTK+ Version 2.8.20)
 of 2007-06-27 on artemis
Windowing system distributor `The X.Org Foundation', version 11.0.70000000
configured using `configure  '--prefix=/home/jbw/local2' '--enable-debug' '--disable-nls' '--with-x-toolkit=gtk' 'CFLAGS=-O0 -g3 -ggdb''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: en_US.UTF-8
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: jbw
  value of $LANG: nil
  locale-coding-system: utf-8
  default-enable-multibyte-characters: t

Minor modes in effect:
  shell-dirtrack-mode: t
  outline-minor-mode: t
  url-handler-mode: t
  partial-completion-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  auto-compression-mode: t
  temp-buffer-resize-mode: t
  size-indication-mode: t
  line-number-mode: t
  transient-mark-mode: t