Comment 28 for bug 61303

On a batch of machines I just dist-upgraded from Breezy to Dapper, Firefox
(and gimp) will segfault when they are run from gnome via XDMCP
(thin-client).

It doesn't segfault from KDE via XDMCP, and it doesn't segfault from
gnome from non-XDMCP X (monitor plugged directly into server). Further, it doesn't segfault when the gnome theme is changed from 'Human' to 'LegacyHuman'.

I installed 'firefox-dbg' and run firefox -g, with the following output:

---
drallen@host:~$ firefox
Segmentation fault
drallen@host:~$ firefox -g
GNU gdb 6.4-debian
Copyright 2005 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu"...Using host libthread_db
library"/lib/libthread_db.so.1".

(gdb) r
Starting program: /usr/lib/firefox/firefox-bin -a firefox
[Thread debugging using libthread_db enabled]
[New Thread 46912551651792 (LWP 7136)]
[New Thread 1082132832 (LWP 7147)]
[New Thread 1090525536 (LWP 7148)]
[New Thread 1098918240 (LWP 7149)]

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 46912551651792 (LWP 7136)]
0x00002aaaac8b4aa3 in _cairo_pixman_composite_tri_fan ()
  from /usr/lib/libcairo.so.2
(gdb) bt
#0 0x00002aaaac8b4aa3 in _cairo_pixman_composite_tri_fan ()
  from /usr/lib/libcairo.so.2
#1 0x00002aaaac8bb66d in _cairo_pixman_composite_tri_fan ()
  from /usr/lib/libcairo.so.2
#2 0x00002aaaac892f10 in cairo_image_surface_get_height ()
  from /usr/lib/libcairo.so.2
#3 0x00002aaaac898296 in cairo_surface_set_device_offset ()
  from /usr/lib/libcairo.so.2
#4 0x00002aaaac890732 in cairo_font_options_get_hint_metrics ()
  from /usr/lib/libcairo.so.2
#5 0x00002aaaac8909e3 in cairo_font_options_get_hint_metrics ()
  from /usr/lib/libcairo.so.2
#6 0x00002aaaac890ca7 in cairo_font_options_get_hint_metrics ()
  from /usr/lib/libcairo.so.2
#7 0x00002aaaac88b00d in cairo_fill_preserve () from /usr/lib/libcairo.so.2
#8 0x00002aaaac88b029 in cairo_fill () from /usr/lib/libcairo.so.2
#9 0x00002aaaafae4cd0 in ubuntulooks_draw_progressbar_trough ()
  from /usr/lib/gtk-2.0/2.4.0/engines/libubuntulooks.so
#10 0x00002aaaafadf0c7 in ubuntulooks_rc_style_register_type ()
  from /usr/lib/gtk-2.0/2.4.0/engines/libubuntulooks.so
#11 0x00002aaaab71ad69 in gtk_progress_bar_new_with_adjustment ()
  from /usr/lib/libgtk-x11-2.0.so.0
#12 0x00002aaaab71908f in gtk_progress_get_type ()
[...]

(I'll attach the entire trace).

I'll also attach a strace for: a segfaulting firefox; and a non-segfaulting firefox (where the only difference is that I've changed the gnome theme from Human to LegacyHuman).

Please let me know if there's anything else I should provide; this is one odd problem.