diff --git a/angr/knowledge/function.py b/angr/knowledge/function.py
index <HASH>..<HASH> 100644
--- a/angr/knowledge/function.py
+++ b/angr/knowledge/function.py
@@ -64,7 +64,7 @@ class Function(object):
             if project.is_hooked(addr):
                 hooker = project.hooked_by(addr)
                 name = hooker.display_name
-            else:
+            elif project._simos.is_syscall_addr(addr):
                 syscall_inst = project._simos.syscall_from_addr(addr)
                 name = syscall_inst.display_name
 
diff --git a/angr/simos.py b/angr/simos.py
index <HASH>..<HASH> 100644
--- a/angr/simos.py
+++ b/angr/simos.py
@@ -246,6 +246,20 @@ class SimOS(object):
             basic_addr = self.project.loader.extern_object.get_pseudo_addr(symbol_name)
         return basic_addr, basic_addr
 
+    # Dummy stuff to allow this API to be used freely
+
+    def syscall(self, state, allow_unsupported=True):
+        return None
+
+    def is_syscall_addr(self, addr):
+        return False
+
+    def syscall_from_addr(self, addr, allow_unsupported=True):
+        return None
+
+    def syscall_from_number(self, number, allow_unsupported=True):
+        return None
+
 
 class SimUserland(SimOS):
     """
Add dummy shim for syscall stuff in SimOS base