(gdb) bt
#0  gen7_update_renderbuffer_surface (brw=0x2b8adf0, rb=0x2d92110, unit=0) at gen7_wm_surface_state.c:471
#1  0x00007fffeef50fb0 in brw_update_renderbuffer_surfaces (brw=0x2b8adf0) at brw_wm_surface_state.c:1205
#2  0x00007fffeef3a442 in brw_upload_state (brw=0x2b8adf0) at brw_state_upload.c:498
#3  0x00007fffeef274a7 in brw_try_draw_prims (max_index=<optimized out>, min_index=<optimized out>, ib=0x7fffffffd7d8, nr_prims=45711736, prim=0x7fffffffd7c0, arrays=<optimized out>,
    ctx=0x2b8adf0) at brw_draw.c:493
#4  brw_draw_prims (ctx=0x2b8adf0, prim=0x7fffffffd7c0, nr_prims=45711736, ib=0x7fffffffd7d8, index_bounds_valid=<optimized out>, min_index=0, max_index=3, tfb_vertcount=0x0) at brw_draw.c:589
#5  0x00007fffeea9f3c9 in vbo_draw_arrays (ctx=0x2b8adf0, mode=6, start=0, count=<optimized out>, numInstances=1, baseInstance=<optimized out>) at ../../../src/mesa/vbo/vbo_exec_array.c:645
#6  0x00007fffeeb4752f in _mesa_meta_glsl_Clear (ctx=0x2b8adf0, buffers=<optimized out>) at ../../../src/mesa/drivers/common/meta.c:2081
#7  0x00007fffeef1aee3 in brw_clear (mask=0, ctx=0x2b8adf0) at brw_clear.c:239
#8  brw_clear (ctx=0x2b8adf0, mask=<optimized out>) at brw_clear.c:208
#9  0x00000000004db1a6 in GL_Clear ()
#10 0x0000000000468a2a in CL_UpdateScreen ()
#11 0x00000000005282b9 in Host_Main ()
#12 0x00000000004047a4 in main ()