Comment 123 for bug 148408

the problem seems to be with radeon_driver.c:9095:xf86ExecX86int10 (pInt); (see attached)

A quick description of the attachments:
gdb.log: probably the most helpful, it's a careful description of all my steps in gdb in order to come to the above conclusion.
xorg.worked.log: as requested, a copy of my xorg.0.log when slowed down by strace enough to work.
xorg_strace_worked.log: the strace that slowed down the above xorg.worked.log - so these both deal with the same VT switch
ltrace.log: ok, this is just a segfault.... when it attached it took down X and I couldn't get anything useful out of it. If an ltrace is required, someone is going to have to give me some tricks to try.

-Devin