Notice, that the www.foo�bar.com has a non-printable UTF-8 character. 

Here is a better backtrace:
Program received signal SIGSEGV, Segmentation fault.
0x019e4801 in IA__g_hostname_to_ascii (hostname=0x85ba9e8 "www.foo�bar.com")
    at /build/buildd/glib2.0-2.23.2/glib/ghostutils.c:402
402	/build/buildd/glib2.0-2.23.2/glib/ghostutils.c: No such file or directory.
	in /build/buildd/glib2.0-2.23.2/glib/ghostutils.c
(gdb) bt
#0  0x019e4801 in IA__g_hostname_to_ascii (hostname=0x85ba9e8 "www.foo�bar.com")
    at /build/buildd/glib2.0-2.23.2/glib/ghostutils.c:402
#1  0x0191a870 in IA__g_resolver_lookup_by_name_async (resolver=0x8181800, 
    hostname=0x85ba9e8 "www.foo�bar.com", cancellable=0x0, callback=0x176c390, user_data=0x828e3b8)
    at /build/buildd/glib2.0-2.23.2/gio/gresolver.c:323
#2  0x0176c266 in soup_address_resolve_async () from /usr/lib/libsoup-2.4.so.1
#3  0x0178d7c4 in soup_session_prepare_for_uri () from /usr/lib/libsoup-2.4.so.1
#4  0x00cea19b in WebCore::prefetchDNS (hostname=...) at ../WebCore/platform/network/soup/DNSSoup.cpp:40
#5  0x00807c17 in WebCore::HTMLAnchorElement::parseMappedAttribute (this=0xb3356240, attr=0xb34df438)
    at ../WebCore/html/HTMLAnchorElement.cpp:282
#6  0x0075e897 in WebCore::StyledElement::attributeChanged (this=0xb3356240, attr=0xb34df438, 
    preserveDecls=false) at ../WebCore/dom/StyledElement.cpp:190
#7  0x0072e0d3 in WebCore::Element::setAttributeMap (this=0xb3356240, list=..., 
    scriptingPermission=WebCore::FragmentScriptingAllowed) at ../WebCore/dom/Element.cpp:668
#8  0x00845416 in WebCore::HTMLParser::parseToken (this=0xb666e6c0, t=0xb666c01c)
    at ../WebCore/html/HTMLParser.cpp:280
#9  0x008582c4 in WebCore::HTMLTokenizer::processToken (this=0xb666c000)
    at ../WebCore/html/HTMLTokenizer.cpp:1939
#10 0x0085bbf8 in WebCore::HTMLTokenizer::parseTag (this=0xb666c000, src=..., state=...)
    at ../WebCore/html/HTMLTokenizer.cpp:1511
#11 0x0085e285 in WebCore::HTMLTokenizer::write (this=0xb666c000, str=..., appendData=false)
    at ../WebCore/html/HTMLTokenizer.cpp:1762
#12 0x00859b75 in WebCore::HTMLTokenizer::executeExternalScriptsIfReady (this=0xb666c000)
    at ../WebCore/html/HTMLTokenizer.cpp:2093
#13 0x008a203c in WebCore::CachedScript::checkNotify (this=0xb6649c00) at ../WebCore/loader/CachedScript.cpp:105
#14 0x008fae38 in WebCore::Loader::Host::didFinishLoading (this=0xb662d540, loader=0xb66cc200)
    at ../WebCore/loader/loader.cpp:391
#15 0x008eaacd in WebCore::SubresourceLoader::didFinishLoading (this=0xb66cc200)
    at ../WebCore/loader/SubresourceLoader.cpp:184
#16 0x008e5321 in WebCore::ResourceLoader::didFinishLoading (this=0xb66cc200)
    at ../WebCore/loader/ResourceLoader.cpp:403
#17 0x00ced21e in finishedCallback (session=0x8180408, msg=0x85b8740, data=0xb66c2e80)
    at ../WebCore/platform/network/soup/ResourceHandleSoup.cpp:332
#18 0x01791341 in ?? () from /usr/lib/libsoup-2.4.so.1
#19 0x019850ec in IA__g_cclosure_marshal_VOID__VOID (closure=0x8180408, return_value=0x0, n_param_values=1, 
    param_values=0x8729918, invocation_hint=0xbfffdb40, marshal_data=0x85fd980)
    at /build/buildd/glib2.0-2.23.2/gobject/gmarshal.c:77
#20 0x01976e52 in IA__g_closure_invoke (closure=0x85f7b98, return_value=0x0, n_param_values=1, 
    param_values=0x8729918, invocation_hint=0xbfffdb40) at /build/buildd/glib2.0-2.23.2/gobject/gclosure.c:767
#21 0x0198d088 in signal_emit_unlocked_R (node=<value optimised out>, detail=<value optimised out>,