Program received signal SIGSEGV, Segmentation fault.
0x00007ffff3227964 in _mesa_compute_max_transform_feedback_vertices (obj=0x6c5dd0, info=0x50) at ../../src/mesa/main/transformfeedback.c:357
357        for (i = 0; i < info->NumBuffers; ++i) {
(gdb) bt
#0  0x00007ffff3227964 in _mesa_compute_max_transform_feedback_vertices (obj=0x6c5dd0, info=0x50) at ../../src/mesa/main/transformfeedback.c:357
#1  0x00007ffff3532d31 in brw_begin_transform_feedback (ctx=0x7ffff7fa4040, mode=0, obj=0x6c5dd0) at gen6_sol.c:258
#2  0x00007ffff3227cd2 in _mesa_BeginTransformFeedback (mode=0) at ../../src/mesa/main/transformfeedback.c:483
#3  0x00007ffff7985410 in glBeginTransformFeedback (mode=0) at ../../src/mapi/glapi/glapi_mapi_tmp.h:7072
#4  0x0000000000401709 in display () at main.c:157
#5  0x00007ffff76b9244 in ?? () from /usr/lib/x86_64-linux-gnu/libglut.so.3
#6  0x00007ffff76bcaa9 in fgEnumWindows () from /usr/lib/x86_64-linux-gnu/libglut.so.3
#7  0x00007ffff76b97fd in glutMainLoopEvent () from /usr/lib/x86_64-linux-gnu/libglut.so.3
#8  0x00007ffff76ba065 in glutMainLoop () from /usr/lib/x86_64-linux-gnu/libglut.so.3
#9  0x00000000004017bb in main (nargs=1, args=0x7fffffffe208) at main.c:177
(gdb) f 0
#0  0x00007ffff3227964 in _mesa_compute_max_transform_feedback_vertices (obj=0x6c5dd0, info=0x50) at ../../src/mesa/main/transformfeedback.c:357
357        for (i = 0; i < info->NumBuffers; ++i) {
(gdb) info args
obj = 0x6c5dd0
info = 0x50
(gdb) f 1
#1  0x00007ffff3532d31 in brw_begin_transform_feedback (ctx=0x7ffff7fa4040, mode=0, obj=0x6c5dd0) at gen6_sol.c:258
258        unsigned max_index
(gdb) info args
ctx = 0x7ffff7fa4040
mode = 0
obj = 0x6c5dd0
(gdb) info locals
brw = 0x7ffff7fa4040
shaderprog = 0x0
linked_xfb_info = 0x50
xfb_obj = 0x6c5dd0
__PRETTY_FUNCTION__ = "brw_begin_transform_feedback"
max_index = 4
(gdb) list -20
228
229        free(brw_obj);
230     }
231
232     void
233     brw_begin_transform_feedback(struct gl_context *ctx, GLenum mode,
234                                  struct gl_transform_feedback_object *obj)
235     {
236        struct brw_context *brw = brw_context(ctx);
237        const struct gl_shader_program *shaderprog;
(gdb) list
238        const struct gl_transform_feedback_info *linked_xfb_info;
239        struct gl_transform_feedback_object *xfb_obj =
240           ctx->TransformFeedback.CurrentObject;
241
242        assert(brw->gen == 6);
243
244        if (brw->geometry_program) {
245           /* BRW_NEW_GEOMETRY_PROGRAM */
246           shaderprog =
247              ctx->_Shader->CurrentProgram[MESA_SHADER_GEOMETRY];
(gdb) list
248        } else {
249           /* BRW_NEW_VERTEX_PROGRAM */
250           shaderprog =
251              ctx->_Shader->CurrentProgram[MESA_SHADER_VERTEX];
252        }
253        linked_xfb_info = &shaderprog->LinkedTransformFeedback;
254
255        /* Compute the maximum number of vertices that we can write without
256         * overflowing any of the buffers currently being used for feedback.
257         */
(gdb) print brw->geometry_program 
$1 = (const struct gl_geometry_program *) 0xaa74b0
(gdb) print ctx->_Shader->CurrentProgram[MESA_SHADER_GEOMETRY]
$2 = (struct gl_shader_program *) 0x0
(gdb) print linked_xfb_info 
$3 = (const struct gl_transform_feedback_info *) 0x50
(gdb) l
258        unsigned max_index
259           = _mesa_compute_max_transform_feedback_vertices(xfb_obj,
260                                                           linked_xfb_info);
261
262        /* 3DSTATE_GS_SVB_INDEX is non-pipelined. */
263        intel_emit_post_sync_nonzero_flush(brw);
264
265        /* Initialize the SVBI 0 register to zero and set the maximum index. */
266        BEGIN_BATCH(4);
267        OUT_BATCH(_3DSTATE_GS_SVB_INDEX << 16 | (4 - 2));
(gdb) print xfb_obj
$4 = (struct gl_transform_feedback_object *) 0x6c5dd0
(gdb) print xfb_obj[0]
$5 = {Name = 0, Label = 0x0, RefCount = 2, Active = 1 '\001', Paused = 0 '\000', EndedAnytime = 0 '\000', EverBound = 1 '\001', shader_program = 0x767650, 
  GlesRemainingPrims = 0, BufferNames = {2, 0, 0, 0}, Buffers = {0x72ba30, 0x0, 0x0, 0x0}, Offset = {0, 0, 0, 0}, Size = {16, 0, 0, 0}, RequestedSize = {0, 0, 0, 0}}