gdb --args glxinfo
GNU gdb (GDB) 7.1-ubuntu
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Reading symbols from /usr/bin/glxinfo...(no debugging symbols found)...done.
(gdb) run
Starting program: /usr/bin/glxinfo 
[Thread debugging using libthread_db enabled]
name of display: :0.0
libGL: XF86DRIGetClientDriverName: 4.3.0 r600 (screen 0)
libGL: OpenDriver: trying /usr/lib/dri/gallium/tls/r600_dri.so
libGL: OpenDriver: trying /usr/lib/dri/gallium/r600_dri.so
drmOpenDevice: node name is /dev/dri/card0
drmOpenDevice: open result is 6, (OK)
drmOpenByBusid: Searching for BusID pci:0000:01:05.0
drmOpenDevice: node name is /dev/dri/card0
drmOpenDevice: open result is 6, (OK)
drmOpenByBusid: drmOpenMinor returns 6
drmOpenByBusid: Interface 1.4 failed, trying 1.1
drmOpenByBusid: drmGetBusid reports pci:0000:01:05.0

Program received signal SIGSEGV, Segmentation fault.
0x00000000 in ?? ()
(gdb) bt
#0  0x00000000 in ?? ()
#1  0x006b4ecd in driCreateNewScreen (scrn=0, ddx_version=0xbffff208, 
    dri_version=0xbffff1fc, drm_version=0xbffff1f0, frame_buffer=0xbffff1d4, 
    pSAREA=0xb7ffb000, fd=6, extensions=0x17e2cc, driver_modes=0xbffff218, 
    loaderPrivate=0x805b628) at ../common/dri_util.c:830
#2  0x0016a820 in CallCreateNewScreen (screen=0, priv=0x805a2e0)
    at dri_glx.c:434
#3  driCreateScreen (screen=0, priv=0x805a2e0) at dri_glx.c:875
#4  0x00147a2c in AllocAndFetchScreenConfigs (dpy=0x8050008) at glxext.c:762
#5  __glXInitialize (dpy=0x8050008) at glxext.c:859
#6  0x0014485a in GetGLXPrivScreenConfig (dpy=0x8050008, scrn=0, 
    ppriv=0xbffff44c, ppsc=0xbffff448) at glxcmds.c:130
#7  0x001459c6 in glXChooseVisual (dpy=0x8050008, screen=0, 
    attribList=0x804f0e0) at glxcmds.c:1152
#8  0x080493a8 in ?? ()
#9  0x0804a44c in ?? ()
#10 0x002f9bd6 in __libc_start_main () from /lib/tls/i686/cmov/libc.so.6
#11 0x08048e11 in ?? ()

This is with xorg-edgers in Ubuntu Lucid, which has Mesa as of 20101122.  I'm running on a 785G.