Comment 2 for bug 941530

StacktraceTop:
 g_str_hash (v=0x0) at /build/buildd/glib2.0-2.31.18/./glib/ghash.c:1730
 g_hash_table_lookup_node (hash_return=<synthetic pointer>, key=0x0, hash_table=0x1b4b520) at /build/buildd/glib2.0-2.31.18/./glib/ghash.c:401
 g_hash_table_lookup (hash_table=0x1b4b520, key=0x0) at /build/buildd/glib2.0-2.31.18/./glib/ghash.c:1074
 g_string_chunk_insert_const (chunk=0x1b4cd60, string=0x0) at /build/buildd/glib2.0-2.31.18/./glib/gstringchunk.c:260
 zeitgeist_subject_set_interpretation (self=0x7ff8dc032b00, value=<optimized out>) at datamodel.c:2876