Repository: pytorch
Issue: DISABLED test_fsdp_unsupported_module_cls (__main__.TestFSDPMiscMultiThread)
Labels: oncall: distributed,triaged,module: flaky-tests,skipped

Platforms: linux

This test was disabled because it is failing in CI. See [recent examples](https://hud.pytorch.org/flakytest?name=test_fsdp_unsupported_module_cls&suite=TestFSDPMiscMultiThread&limit=100) and the most recent trunk [workflow logs](https://github.com/pytorch/pytorch/runs/31522119419).

Over the past 3 hours, it has been determined flaky in 5 workflow(s) with 5 failures and 5 successes.

**Debugging instructions (after clicking on the recent samples link):**
DO NOT ASSUME THINGS ARE OKAY IF THE CI IS GREEN. We now shield flaky tests from developers so CI will thus be green but it will be harder to parse the logs.
To find relevant log snippets:
1. Click on the workflow logs linked above
2. Click on the Test step of the job so that it is expanded. Otherwise, the grepping will not work.
3. Grep for `test_fsdp_unsupported_module_cls`
4. There should be several instances run (as flaky tests are rerun in CI) from which you can study the logs.



<details><summary>Sample error message</summary>

```
Traceback (most recent call last):
  File "/opt/conda/envs/py_3.10/lib/python3.10/site-packages/torch/testing/_internal/common_distributed.py", line 1004, in wrapper
    self._join_threads(self.threads, fn)
  File "/opt/conda/envs/py_3.10/lib/python3.10/site-packages/torch/testing/_internal/common_distributed.py", line 1135, in _join_threads
    cls._check_return_codes(failed_ranks, timeout, fn)
  File "/opt/conda/envs/py_3.10/lib/python3.10/site-packages/torch/testing/_internal/common_distributed.py", line 1172, in _check_return_codes
    raise RuntimeError(error_msg)
RuntimeError: Thread 1 exited with exception:
Traceback (most recent call last):
  File "/opt/conda/envs/py_3.10/lib/python3.10/site-packages/torch/testing/_internal/common_distributed.py", line 1098, in run_test_with_threaded_pg
    getattr(self, test_name)()
  File "/opt/conda/envs/py_3.10/lib/python3.10/site-packages/torch/testing/_internal/common_distributed.py", line 1006, in wrapper
    fn()
  File "/opt/conda/envs/py_3.10/lib/python3.10/site-packages/torch/testing/_internal/common_utils.py", line 2983, in wrapper
    method(*args, **kwargs)
  File "/opt/conda/envs/py_3.10/lib/python3.10/site-packages/torch/testing/_internal/common_distributed.py", line 184, in wrapper
    return func(*args, **kwargs)
  File "/var/lib/jenkins/workspace/test/distributed/fsdp/test_fsdp_misc.py", line 978, in test_fsdp_unsupported_module_cls
    with self.assertWarnsRegex(UserWarning, regex):
  File "/opt/conda/envs/py_3.10/lib/python3.10/unittest/case.py", line 295, in __exit__
    self._raiseFailure("{} not triggered".format(exc_name))
  File "/opt/conda/envs/py_3.10/lib/python3.10/unittest/case.py", line 163, in _raiseFailure
    raise self.test_case.failureException(msg)
AssertionError: UserWarning not triggered

To execute this test, run the following from the base repo dir:
    python test/distributed/fsdp/test_fsdp_misc.py TestFSDPMiscMultiThread.test_fsdp_unsupported_module_cls

This message can be suppressed by setting PYTORCH_PRINT_REPRO_ON_FAILURE=0
```

</details>


Test file path: `distributed/fsdp/test_fsdp_misc.py`

cc @XilunWu @H-Huang @awgu @kwen2501 @wanchaol @fegin @fduwjj @wz337 @wconstab @d4l3k @c-p-i-o @clee2000