9815713497c5:/bitcoin # ./test/functional/wallet_backup.py --descriptors
2021-11-21T07:11:10.648000Z TestFramework (INFO): Initializing test directory /tmp/bitcoin_func_test_ma4r2esy
2021-11-21T07:11:11.514000Z TestFramework (INFO): Generating initial blockchain
2021-11-21T07:11:15.931000Z TestFramework (INFO): Creating transactions
2021-11-21T07:11:30.282000Z TestFramework (INFO): Backing up
2021-11-21T07:11:30.303000Z TestFramework (INFO): More transactions
2021-11-21T07:11:43.899000Z TestFramework (INFO): Restoring wallets on node 3 using backup files
2021-11-21T07:11:44.287000Z TestFramework (ERROR): Unexpected exception caught during testing
Traceback (most recent call last):
  File "/bitcoin/test/functional/test_framework/authproxy.py", line 108, in _request
    return self._get_response()
  File "/bitcoin/test/functional/test_framework/authproxy.py", line 166, in _get_response
    http_response = self.__conn.getresponse()
  File "/usr/lib64/python3.8/http/client.py", line 1348, in getresponse
    response.begin()
  File "/usr/lib64/python3.8/http/client.py", line 316, in begin
    version, status, reason = self._read_status()
  File "/usr/lib64/python3.8/http/client.py", line 285, in _read_status
    raise RemoteDisconnected("Remote end closed connection without"
http.client.RemoteDisconnected: Remote end closed connection without response

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/bitcoin/test/functional/test_framework/test_framework.py", line 132, in main
    self.run_test()
  File "./test/functional/wallet_backup.py", line 186, in run_test
    self.nodes[3].restorewallet("res0", backup_file_0)
  File "/bitcoin/test/functional/test_framework/coverage.py", line 49, in __call__
    return_val = self.auth_service_proxy_instance.__call__(*args, **kwargs)
  File "/bitcoin/test/functional/test_framework/authproxy.py", line 142, in __call__
    response, status = self._request('POST', self.__url.path, postdata.encode('utf-8'))
  File "/bitcoin/test/functional/test_framework/authproxy.py", line 113, in _request
    self.__conn.request(method, path, postdata, headers)
  File "/usr/lib64/python3.8/http/client.py", line 1256, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/usr/lib64/python3.8/http/client.py", line 1302, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
  File "/usr/lib64/python3.8/http/client.py", line 1251, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "/usr/lib64/python3.8/http/client.py", line 1011, in _send_output
    self.send(msg)
  File "/usr/lib64/python3.8/http/client.py", line 951, in send
    self.connect()
  File "/usr/lib64/python3.8/http/client.py", line 922, in connect
    self.sock = self._create_connection(
  File "/usr/lib64/python3.8/socket.py", line 808, in create_connection
    raise err
  File "/usr/lib64/python3.8/socket.py", line 796, in create_connection
    sock.connect(sa)
ConnectionRefusedError: [Errno 111] Connection refused
2021-11-21T07:11:44.339000Z TestFramework (INFO): Stopping nodes
2021-11-21T07:11:44.343000Z TestFramework.node3 (ERROR): Unable to stop node.
Traceback (most recent call last):
  File "/bitcoin/test/functional/test_framework/test_node.py", line 335, in stop_node
    self.stop(wait=wait)
  File "/bitcoin/test/functional/test_framework/coverage.py", line 49, in __call__
    return_val = self.auth_service_proxy_instance.__call__(*args, **kwargs)
  File "/bitcoin/test/functional/test_framework/authproxy.py", line 142, in __call__
    response, status = self._request('POST', self.__url.path, postdata.encode('utf-8'))
  File "/bitcoin/test/functional/test_framework/authproxy.py", line 107, in _request
    self.__conn.request(method, path, postdata, headers)
  File "/usr/lib64/python3.8/http/client.py", line 1256, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/usr/lib64/python3.8/http/client.py", line 1267, in _send_request
    self.putrequest(method, url, **skips)
  File "/usr/lib64/python3.8/http/client.py", line 1093, in putrequest
    raise CannotSendRequest(self.__state)
http.client.CannotSendRequest: Request-sent
Traceback (most recent call last):
  File "./test/functional/wallet_backup.py", line 238, in <module>
    WalletBackupTest().main()
  File "/bitcoin/test/functional/test_framework/test_framework.py", line 155, in main
    exit_code = self.shutdown()
  File "/bitcoin/test/functional/test_framework/test_framework.py", line 304, in shutdown
    self.stop_nodes()
  File "/bitcoin/test/functional/test_framework/test_framework.py", line 555, in stop_nodes
    node.stop_node(wait=wait, wait_until_stopped=False)
  File "/bitcoin/test/functional/test_framework/test_node.py", line 349, in stop_node
    raise AssertionError("Unexpected stderr {} != {}".format(stderr, expected_stderr))
AssertionError: Unexpected stderr ERROR: The syscall "fstatfs" (syscall number 138) is not allowed by the syscall sandbox in thread "httpworker.2". Please report.
terminate called without an active exception != 
[node 3] Cleaning up leftover process
[node 2] Cleaning up leftover process
[node 1] Cleaning up leftover process
[node 0] Cleaning up leftover process