Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1263252560 (LWP 6239)]
0x08446205 in ambient_occlusion (shi=0xb4b3f454)
    at source/blender/render/intern/source/shadeoutput.c:971
971             if((R.r.mode & R_RAYTRACE) && shi->mat->amb!=0.0f)
(gdb) bt
#0  0x08446205 in ambient_occlusion (shi=0xb4b3f454)
    at source/blender/render/intern/source/shadeoutput.c:971
#1  0x0843d5b4 in shade_samples_do_AO (ssamp=0xb4b3efa4)
    at source/blender/render/intern/source/shadeinput.c:919
#2  0x08440ed4 in shade_sample_sss (ssamp=0xb4b3efa4, mat=0x8f89060,
    vlr=0x8f6fb84, quad=134217728, x=354, y=150, z=2.1112352e+09,
    co=0xb4267028, color=0xb4200028, area=0xb41dd028)
    at source/blender/render/intern/source/rendercore.c:1219
#3  0x08441474 in zbufshade_sss_tile (pa=0x8f63640)
    at source/blender/render/intern/source/rendercore.c:1341
#4  0x08410de0 in do_part_thread (pa_v=0x8f63640)
    at source/blender/render/intern/source/pipeline.c:1169
#5  0xb7654341 in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#6  0xb77504ee in clone () from /lib/tls/i686/cmov/libc.so.6