diff --git a/python/hidet/backend/codegen.py b/python/hidet/backend/codegen.py
index 567009068..7791944a0 100644
--- a/python/hidet/backend/codegen.py
+++ b/python/hidet/backend/codegen.py
@@ -237,7 +237,7 @@ def visit_Function(self, func: Function) -> Doc:
         doc += ') {'
 
         # comments
-        label = func.get_attr('label')
+        label = func.get_attr('label', default=None, allow_missing=True)
         if label:
             doc += (NewLine() + '// label: {}'.format(label)).indent()
 
diff --git a/python/hidet/ir/func.py b/python/hidet/ir/func.py
index 7547691eb..cc4ea2ed8 100644
--- a/python/hidet/ir/func.py
+++ b/python/hidet/ir/func.py
@@ -72,15 +72,40 @@ def __init__(self, name: str, params, body, ret_type, kind: str, extern_vars=Non
     def __call__(self, *args, **kwargs) -> Call:
         raise ValueError('Can only call script function in another script function, or lower it to execute.')
 
-    def get_attr(self, attr_name, default=None):
+    def get_attr(self, attr_name, default=None, allow_missing=False):
+        """
+        Get attribute of this function.
+
+        When default is not None or allow_missing is True, this function will return the default value (in case
+        default is not None) or None (in case default is None) when the attribute is not found. Otherwise,
+        this function will raise a KeyError.
+
+        Parameters
+        ----------
+        attr_name: str
+            The name of attribute
+
+        default: Any, optional
+            The default value of attribute
+
+        allow_missing: bool, default False
+
+        Returns
+        -------
+        attr_value: Any
+            The value of attribute
+        """
         if attr_name in self.attrs:
             return self.attrs[attr_name]
-        return default
+        if default is not None or allow_missing:
+            return default
+        else:
+            raise KeyError('Attribute {} is not found in function {}'.format(attr_name, self.name))
 
 
 class IRModule(Node):
     """
-    The intermidiate representation of tensor programs.
+    The intermediate representation of tensor programs.
 
     An IRModule contains one or more functions. It is the basic compilation unit of hidet.
     """
diff --git a/python/hidet/transforms/generate_packed_func.py b/python/hidet/transforms/generate_packed_func.py
index 18b14edc6..66c3f7e66 100644
--- a/python/hidet/transforms/generate_packed_func.py
+++ b/python/hidet/transforms/generate_packed_func.py
@@ -28,11 +28,12 @@ def process_module(self, ir_module: IRModule) -> IRModule:
             if func.kind not in ['cuda_kernel', 'host_kernel']:
                 # only generate packed func for entry function
                 continue
-            if func.get_attr('packed_func', None) is not None:
+            if func.get_attr('packed_func', allow_missing=True) is not None:
                 # this function itself is a packed function
                 continue
             if any(
-                f.get_attr('packed_func', None) is ir_module.lookup_var(func.name) for f in ir_module.functions.values()
+                f.get_attr('packed_func', allow_missing=True) is ir_module.lookup_var(func.name)
+                for f in ir_module.functions.values()
             ):
                 # the packed function for current function has existed, skip
                 continue
diff --git a/python/hidet/transforms/tools/generate_packed_func.py b/python/hidet/transforms/tools/generate_packed_func.py
index f8773d301..ce250c546 100644
--- a/python/hidet/transforms/tools/generate_packed_func.py
+++ b/python/hidet/transforms/tools/generate_packed_func.py
@@ -86,7 +86,7 @@ def extract_params_and_call(num_args: Expr, arg_types: Expr, args: Expr) -> Stmt
                 [param2arg[param] for param in func.params],
                 grid_dim=_rewrite_dim3(_normalize_dim3(func.get_attr('cuda_grid_dim')), param2arg),
                 block_dim=_rewrite_dim3(_normalize_dim3(func.get_attr('cuda_block_dim')), param2arg),
-                shared_mem=rewrite(int32(func.get_attr('shared_mem', 0)), param2arg),
+                shared_mem=rewrite(int32(func.get_attr('cuda_dynamic_smem_bytes', 0)), param2arg),
             )
         elif func.kind == 'host_kernel':
             sb += Call(func_var, [param2arg[param] for param in func.params])