[Dynamo] Catch unserialisable NN modules (#153503)

Pull Request resolved: https://github.com/pytorch/pytorch/pull/153503
Approved by: https://github.com/c00w, https://github.com/jansel

test/dynamo/test_modules.py

@@ -3359,6 +3359,24 @@ class OptimizedModuleTest(torch._dynamo.test_case.TestCase):
         res = compiled_module(input_tensor)
         self.assertEqual(ref, res)
 
+    def test_unhashable_nn_submodule(self):
+        class UnhashableModule(torch.nn.Module):
+            def __hash__(self):
+                raise TypeError("Unhashable module")
+
+        class MyModule(torch.nn.Module):
+            def __init__(self):
+                super().__init__()
+                self.unhashable_attr = UnhashableModule()
+
+            def forward(self, x):
+                return x
+
+        mod = MyModule()
+        x = torch.randn(1)
+        compiled_mod = torch.compile(mod, backend="eager")
+        compiled_mod(x)
+
 
 devices = ["cuda", "hpu"]
 instantiate_device_type_tests(NNModuleTestsDevice, globals(), only_for=devices)

torch/_dynamo/variables/builder.py

@@ -78,7 +78,7 @@ from torch.utils.weak import TensorWeakRef
 
 from .. import config, graph_break_hints, mutation_guard, replay_record, trace_rules
 from ..device_interface import get_registered_device_interfaces
-from ..exc import InternalTorchDynamoError, unimplemented_v2
+from ..exc import InternalTorchDynamoError, raise_observed_exception, unimplemented_v2
 from ..guards import GuardBuilder, install_guard, make_dupe_guard
 from ..pgo import (
     auto_dynamic,
@@ -1686,6 +1686,7 @@ class VariableBuilder:
             self.install_guards(GuardBuilder.TYPE_MATCH)
             if torch._dynamo.config.inline_inbuilt_nn_modules:
                 freezing = is_parameter_freezing()
+
                 # Guard against the case where user may overwrite named parameters
                 # / named buffers
                 # NOTE: This is not likely to happen but worth guarding to avoid
@@ -1695,15 +1696,21 @@ class VariableBuilder:
                     and value.named_parameters.__func__
                     is og_module_named_parameters_fn_ptr
                 ):
+                    try:  # catch TypeErrors in named_parameters() from unserializable nn modules
                         for _, p in value.named_parameters():
                             self.mark_static_input(p, guard=freezing)
+                    except TypeError as e:
+                        raise_observed_exception(type(e), self.tx, args=list(e.args))
 
                 if (
                     callable(value.named_buffers)
                     and value.named_buffers.__func__ is og_module_named_buffers_fn_ptr
                 ):
+                    try:  # catch TypeErrors in named_parameters() from unserializable nn modules
                         for _, b in value.named_buffers():
                             self.mark_static_input(b, guard=freezing)
+                    except TypeError as e:
+                        raise_observed_exception(type(e), self.tx, args=list(e.args))
 
                 if freezing:
                     # we need to add the module to tracing context