__assert_fail_base (fmt=0xb6dfaff4 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", assertion=assertion@entry=0xb6bb8c44 "((*&(&surface->ref_count)->ref_count) > 0)", file=file@entry=0xb6bb8bc0 "/build/buildd/cairo-1.13.0~20140204/src/cairo-surface.c", line=line@entry=953, function=function@entry=0xb6bb90fe <__PRETTY_FUNCTION__.10934> "cairo_surface_destroy") at assert.c:92
__GI___assert_fail (assertion=assertion@entry=0xb6bb8c44 "((*&(&surface->ref_count)->ref_count) > 0)", file=file@entry=0xb6bb8bc0 "/build/buildd/cairo-1.13.0~20140204/src/cairo-surface.c", line=line@entry=953, function=function@entry=0xb6bb90fe <__PRETTY_FUNCTION__.10934> "cairo_surface_destroy") at assert.c:101
INT_cairo_surface_destroy (surface=surface@entry=0x9ab7e00) at /build/buildd/cairo-1.13.0~20140204/src/cairo-surface.c:953
_get_image_surface (surface=surface@entry=0x9ac01d8, extents=extents@entry=0xbfe636c0, try_shm=try_shm@entry=1) at /build/buildd/cairo-1.13.0~20140204/src/cairo-xlib-surface.c:1014
_cairo_xlib_surface_acquire_source_image (abstract_surface=0x9ac01d8, image_out=0xbfe637c0, image_extra=0xbfe637f0) at /build/buildd/cairo-1.13.0~20140204/src/cairo-xlib-surface.c:1403