.
Thread 1 (Thread 0xb73746c0 (LWP 4951)):
#0  composite_line (weights=0xa5f6800, n_x=2, n_y=2, dest=0xb54ec21c <Address 0xb54ec21c out of bounds>, dest_x=0, dest_end=0xb54ec258 <Address 0xb54ec258 out of bounds>, dest_channels=4, dest_has_alpha=1, src=0xa5fc880, src_channels=4, src_has_alpha=1, x_init=0, x_step=65536, src_width=16, check_size=0, color1=0, color2=0) at pixops.c:637
        w0 = <optimized out>
        w1 = 16646400
        w = 16646400
        g = <optimized out>
        a = <optimized out>
        x_scaled = 0
        r = <optimized out>
        b = <optimized out>
        pixel_weights = <optimized out>
        x = 0
        i = <optimized out>
        j = <optimized out>
#1  0xb624c44f in pixops_process (dest_buf=0xb54ec21c <Address 0xb54ec21c out of bounds>, render_x0=0, render_y0=0, render_x1=16, render_y1=16, dest_rowstride=192, dest_channels=4, dest_has_alpha=1, src_buf=0xa5f8c00 "", src_width=16, src_height=16, src_rowstride=64, src_channels=4, src_has_alpha=1, scale_x=1, scale_y=1, check_x=0, check_y=0, check_size=0, color1=0, color2=0, filter=0xbfa64098, line_func=0xb624a360 <composite_line>, pixel_func=0xb624b650 <composite_pixel>) at pixops.c:1352
        x_start = <optimized out>
        run_weights = 0xa5f6800
        new_outbuf = <optimized out>
        tcolor2 = 0
        dest_x = 0
        y_start = <optimized out>
        tcolor1 = 0
        outbuf = <optimized out>
        outbuf_end = 0xb54ec25c <Address 0xb54ec25c out of bounds>
        i = <optimized out>
        j = <optimized out>
        x = <optimized out>
        y = <optimized out>
        line_bufs = 0xa5fc880
        filter_weights = 0xa5f6800
        x_step = 65536
        y_step = 65536
        check_shift = <optimized out>
        scaled_x_offset = 0
        run_end_x = <optimized out>
        run_end_index = <optimized out>
#2  0xb624d3dc in _pixops_composite_real (overall_alpha=255, interp_type=PIXOPS_INTERP_BILINEAR, scale_y=1, scale_x=<optimized out>, src_has_alpha=1, src_channels=4, src_rowstride=64, src_height=16, src_width=16, src_buf=0xa5f8c00 "", dest_has_alpha=1, dest_channels=4, dest_rowstride=192, render_y1=<optimized out>, render_x1=<optimized out>, render_y0=<optimized out>, render_x0=<optimized out>, dest_buf=0xb54ec21c <Address 0xb54ec21c out of bounds>) at pixops.c:1810
        filter = {x = {n = 2, offset = 0, weights = 0xa5c51b8}, y = {n = 2, offset = 0, weights = 0xa5d0fa8}, overall_alpha = 1}
        line_func = <optimized out>
        found_mmx = <optimized out>
#3  _pixops_composite (dest_buf=0xb54eae34 <Address 0xb54eae34 out of bounds>, dest_width=48, dest_height=48, dest_rowstride=192, dest_channels=4, dest_has_alpha=1, src_buf=0xa5f8c00 "", src_width=16, src_height=16, src_rowstride=64, src_channels=4, src_has_alpha=1, dest_x=26, dest_y=26, dest_region_width=16, dest_region_height=16, offset_x=26, offset_y=26, scale_x=1, scale_y=1, interp_type=PIXOPS_INTERP_BILINEAR, overall_alpha=255) at pixops.c:1877
        new_dest_buf = 0xb54ec21c <Address 0xb54ec21c out of bounds>
#4  0xb62434f4 in gdk_pixbuf_composite (src=0xa5bd838, dest=0xa5adf50, dest_x=26, dest_y=26, dest_width=16, dest_height=16, offset_x=<optimized out>, offset_y=<optimized out>, scale_x=1, scale_y=1, interp_type=GDK_INTERP_BILINEAR, overall_alpha=255) at gdk-pixbuf-scale.c:214
        __PRETTY_FUNCTION__ = "gdk_pixbuf_composite"
#5  0xb6cb735a in ffi_call_SYSV () at ../src/x86/sysv.S:64
No locals.
#6  0xb6cb708f in ffi_call (cif=0xbfa6432c, fn=0xb6243280 <gdk_pixbuf_composite>, rvalue=0xbfa64454, avalue=0xbfa64260) at ../src/x86/ffi.c:303
        ecif = {cif = 0xbfa6432c, rvalue = 0xbfa64454, avalue = 0xbfa64260}
#7  0xb6f7229b in _g_callable_info_invoke (info=0xa5acb50, function=0xb6243280, in_args=0x9f64ce0, n_in_args=12, out_args=0x0, n_out_args=0, return_value=0xbfa64454, is_method=1, throws=0, error=0xbfa64464) at girepository/gicallableinfo.c:518
        cif = {abi = FFI_SYSV, nargs = 12, arg_types = 0xbfa642a0, rtype = 0xb6cb75e4, bytes = 64, flags = 0}
        rtype = 0xb6cb75e4
        atypes = 0xbfa642a0
        tinfo = <optimized out>
        ainfo = <optimized out>
        n_args = 11
        n_invoke_args = 12
        in_pos = 12
        out_pos = <optimized out>
        i = <optimized out>
        args = 0xbfa64260
        local_error = 0x0
        error_address = 0xbfa64344
        __PRETTY_FUNCTION__ = "_g_callable_info_invoke"
#8  0xb6f73891 in g_function_info_invoke (info=0xa5acb50, in_args=0x9f64ce0, n_in_args=12, out_args=0x0, n_out_args=0, return_value=0xbfa64454, error=0xbfa64464) at girepository/gifunctioninfo.c:273
        symbol = <optimized out>
        func = 0xb6243280
        is_method = 1
        throws = <optimized out>
#9  0xb6fb1037 in _arg_cache_new_for_interface (iface_info=0xc, callable_cache=0xa58714c, arg_info=0xc, transfer=GI_TRANSFER_NOTHING, direction=PYGI_DIRECTION_TO_PYTHON, c_arg_index=173737760, py_arg_index=167136480) at /build/buildd/pygobject-3.1.1/gi/pygi-cache.c:797
        callback_cache = 0xbfa64464
        iface_cache = <optimized out>
        arg_cache = <optimized out>
        child_offset = 164200528
        info_type = <optimized out>
        __PRETTY_FUNCTION__ = "_arg_cache_new_for_interface"
#10 0x0827e980 in ?? ()
No symbol table info available.
Backtrace stopped: previous frame inner to this frame (corrupt stack?)