Comment 2 for bug 830563

StacktraceTop:
 lookup_composite_function (out_func=<optimized out>, out_imp=<optimized out>, dest_flags=<optimized out>, dest_format=<optimized out>, mask_flags=<optimized out>, mask_format=<optimized out>, src_flags=<optimized out>, src_format=<optimized out>, op=<optimized out>) at ../../pixman/pixman.c:378
 pixman_image_composite32 (op=<optimized out>, src=0x9f8c270, mask=0x0, dest=0x9f5f998, src_x=0, src_y=0, mask_x=0, mask_y=0, dest_x=0, dest_y=0, width=80, height=80) at ../../pixman/pixman.c:767
 _cairo_pattern_acquire_surface_for_gradient (attr=0xbfaf1e30, out=0xbfaf1ed0, height=80, width=80, y=0, x=0, dst=0x9f8d858, pattern=0xbfaf28c8) at /build/buildd/cairo-1.10.2/src/cairo-pattern.c:1524
 _cairo_pattern_acquire_surface (pattern=0xbfaf28c8, dst=0x9f8d858, x=0, y=0, width=80, height=80, flags=0, surface_out=0xbfaf1ed0, attributes=0xbfaf1e30) at /build/buildd/cairo-1.10.2/src/cairo-pattern.c:2534
 _cairo_pattern_acquire_surfaces (src=0xbfaf28c8, mask=0x0, dst=0x9f8d858, src_x=0, src_y=0, mask_x=0, mask_y=0, width=80, height=80, flags=0, src_out=0xbfaf1ed0, mask_out=0xbfaf1ed4, src_attributes=0xbfaf1e30, mask_attributes=0xbfaf1e78) at /build/buildd/cairo-1.10.2/src/cairo-pattern.c:2613