diff -r f3c36747f019 libgo/runtime/go-caller.c
--- a/libgo/runtime/go-caller.c	Thu Apr 30 13:40:30 2015 -0700
+++ b/libgo/runtime/go-caller.c	Tue May 05 07:12:06 2015 -0700
@@ -231,6 +231,8 @@
 String
 runtime_funcname_go (Func *f)
 {
+  if (f == NULL)
+    return runtime_gostringnocopy ((const byte *) "");
   return f->name;
 }