Attached a .blend as an example.

If you Duplivert a buffered spot on a mesh and then enable the Show Cone feature on that Spot lamp, Blender crashes.

GDB backtrace:

Program received signal SIGSEGV, Segmentation fault.
0x0000000000931fae in draw_object (scene=0x3c91048, ar=0x3c61b98,
v3d=0x3c620b8, base=0x7fffffffddb0, flag=2)
at source/blender/editors/space_view3d/drawobject.c:5620
5620 if(!(ob->mode & OB_MODE_PARTICLE_EDIT)) {
(gdb) bt
#0 0x0000000000931fae in draw_object (scene=0x3c91048, ar=0x3c61b98,
v3d=0x3c620b8, base=0x7fffffffddb0, flag=2)
at source/blender/editors/space_view3d/drawobject.c:5620
#1 0x00000000009544ad in view3d_draw_transp (scene=0x3c91048, ar=0x3c61b98,
v3d=0x3c620b8) at source/blender/editors/space_view3d/view3d_draw.c:1397
#2 0x000000000095742e in view3d_main_area_draw (C=0x1f6e108, ar=0x3c61b98)
at source/blender/editors/space_view3d/view3d_draw.c:2452
#3 0x0000000000b2ff58 in ED_region_do_draw (C=0x1f6e108, ar=0x3c61b98)
at source/blender/editors/screen/area.c:344
#4 0x00000000008e18b1 in wm_method_draw_triple (C=0x1f6e108, win=0x3b3ecc8)
at source/blender/windowmanager/intern/wm_draw.c:593
#5 0x00000000008e1fa8 in wm_draw_update (C=0x1f6e108)
at source/blender/windowmanager/intern/wm_draw.c:770
#6 0x00000000008ca9f9 in WM_main (C=0x1f6e108)
at source/blender/windowmanager/intern/wm.c:348
#7 0x00000000008c7e0a in main (argc=1, argv=0x7fffffffe168)
at source/creator/creator.c:1195