(gdb) bt
#0  0x00000000 in ?? ()
#1  0xb78e2f12 in clip_quad_4 (ctx=0x805f570, v0=Variable "v0" is not available.
) at t_vb_cliptmp.h:281
#2  0xb78e3e8b in clip_render_quad_strip_verts (ctx=0x805f570, start=0,
    count=82, flags=56) at t_vb_rendertmp.h:378
#3  0xb78e6752 in run_render (ctx=0x805f570, stage=0x82c7d68)
    at t_vb_render.c:320
#4  0xb78d45f3 in _tnl_run_pipeline (ctx=0x805f570) at t_pipeline.c:159
#5  0xb785a9c3 in nouveauRunPipeline (ctx=0x805f570) at nouveau_swtcl.c:124
#6  0xb78d9b66 in _tnl_playback_vertex_list (ctx=0x805f570, data=0x873e6b4)
    at t_save_playback.c:210
#7  0xb787d81a in execute_list (ctx=0x805f570, list=Variable "list" is not available.
) at dlist.c:5783
#8  0xb788010f in _mesa_CallList (list=1) at dlist.c:6875
#9  0xb78cdbc5 in neutral_CallList (i=1) at vtxfmt_tmp.h:298
#10 0x08049afb in ?? ()