LayoutTests/svg/custom/resource-invalidation-crash.svg

<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<defs>

    <pattern id="a" />
    <pattern id="b" >
        <rect  fill="url(#a)"/>
    </pattern>

    <pattern id="a" xlink:href="#b"/>
    <pattern id="b" >
        <rect  fill="url(#a)"/>
    </pattern>

    <pattern id="a" xlink:href="#b"/>
        <rect  fill="url(#a)"/>

</defs>

</svg>