s390x RHEL8 Refleaks 3.10:
https://buildbot.python.org/all/#/builders/669/builds/121

Reformatted output:

0:19:31 load avg: 2.74 [316/427/1] test_asyncio failed (env changed) (14 min 36 sec) -- running: test_statistics (37.6 sec), test_signal (16 min 51 sec), test_pydoc (5 min 36 sec), test_xmlrpc (1 min 49 sec), test_subprocess (1 min 15 sec)
beginning 6 repetitions
123456

Unknown child process pid 1398289, will report returncode 255
Loop <_UnixSelectorEventLoop running=False closed=True debug=False> that handles pid 1398289 is closed

.

Unknown child process pid 1404140, will report returncode 255
Loop <_UnixSelectorEventLoop running=False closed=True debug=False> that handles pid 1404140 is closed

.

/home/dje/cpython-buildarea/3.10.edelsohn-rhel8-z.refleak/build/Lib/asyncio/sslproto.py:320: ResourceWarning: unclosed transport <asyncio.sslproto._SSLProtocolTransport object at 0x3ffb8cc9da0>
  _warn(f"unclosed transport {self!r}", ResourceWarning, source=self)
ResourceWarning: Enable tracemalloc to get the object allocation traceback

Warning -- Unraisable exception
Exception ignored in: <function _SSLProtocolTransport.__del__ at 0x3ffba2adde0>
Traceback (most recent call last):
  File "/home/dje/cpython-buildarea/3.10.edelsohn-rhel8-z.refleak/build/Lib/asyncio/sslproto.py", line 321, in __del__
    self.close()
  File "/home/dje/cpython-buildarea/3.10.edelsohn-rhel8-z.refleak/build/Lib/asyncio/sslproto.py", line 316, in close
    self._ssl_protocol._start_shutdown()
  File "/home/dje/cpython-buildarea/3.10.edelsohn-rhel8-z.refleak/build/Lib/asyncio/sslproto.py", line 590, in _start_shutdown
    self._abort()
  File "/home/dje/cpython-buildarea/3.10.edelsohn-rhel8-z.refleak/build/Lib/asyncio/sslproto.py", line 731, in _abort
    self._transport.abort()
  File "/home/dje/cpython-buildarea/3.10.edelsohn-rhel8-z.refleak/build/Lib/asyncio/selector_events.py", line 680, in abort
    self._force_close(None)
  File "/home/dje/cpython-buildarea/3.10.edelsohn-rhel8-z.refleak/build/Lib/asyncio/selector_events.py", line 731, in _force_close
    self._loop.call_soon(self._call_connection_lost, exc)
  File "/home/dje/cpython-buildarea/3.10.edelsohn-rhel8-z.refleak/build/Lib/asyncio/base_events.py", line 745, in call_soon
    self._check_closed()
  File "/home/dje/cpython-buildarea/3.10.edelsohn-rhel8-z.refleak/build/Lib/asyncio/base_events.py", line 510, in _check_closed
    raise RuntimeError('Event loop is closed')
RuntimeError: Event loop is closed

/home/dje/cpython-buildarea/3.10.edelsohn-rhel8-z.refleak/build/Lib/asyncio/selector_events.py:704: ResourceWarning: unclosed transport <_SelectorSocketTransport closing fd=9>
  _warn(f"unclosed transport {self!r}", ResourceWarning, source=self)
ResourceWarning: Enable tracemalloc to get the object allocation traceback

Task was destroyed but it is pending!
task: <Task pending name='Task-8581' coro=<BaseSelectorEventLoop._accept_connection2() running at /home/dje/cpython-buildarea/3.10.edelsohn-rhel8-z.refleak/build/Lib/asyncio/selector_events.py:218> wait_for=<Future pending cb=[Task.task_wakeup()]>>

Unknown child process pid 1411156, will report returncode 255
Loop <_UnixSelectorEventLoop running=False closed=True debug=False> that handles pid 1411156 is closed

.

Unknown child process pid 1415148, will report returncode 255
Loop <_UnixSelectorEventLoop running=False closed=True debug=False> that handles pid 1415148 is closed

..

Unknown child process pid 1426190, will report returncode 255
Loop <_UnixSelectorEventLoop running=False closed=True debug=False> that handles pid 1426190 is closed

.

PPC64LE RHEL8 LTO 3.10:
https://buildbot.python.org/all/#/builders/680/builds/279

0:01:14 load avg: 8.67 [236/427/1] test_asyncio failed (env changed) (1 min 5 sec) -- running: test_gdb (1 min 2 sec), test_tokenize (47.0 sec)
Warning -- Unraisable exception
Exception ignored in: <function _SSLProtocolTransport.__del__ at 0x7fffa2979ab0>
Traceback (most recent call last):
  File "/home/buildbot/buildarea/3.10.cstratak-RHEL8-ppc64le.lto/build/Lib/asyncio/sslproto.py", line 321, in __del__
    self.close()
  File "/home/buildbot/buildarea/3.10.cstratak-RHEL8-ppc64le.lto/build/Lib/asyncio/sslproto.py", line 316, in close
    self._ssl_protocol._start_shutdown()
  File "/home/buildbot/buildarea/3.10.cstratak-RHEL8-ppc64le.lto/build/Lib/asyncio/sslproto.py", line 590, in _start_shutdown
    self._abort()
  File "/home/buildbot/buildarea/3.10.cstratak-RHEL8-ppc64le.lto/build/Lib/asyncio/sslproto.py", line 731, in _abort
    self._transport.abort()
  File "/home/buildbot/buildarea/3.10.cstratak-RHEL8-ppc64le.lto/build/Lib/asyncio/selector_events.py", line 680, in abort
    self._force_close(None)
  File "/home/buildbot/buildarea/3.10.cstratak-RHEL8-ppc64le.lto/build/Lib/asyncio/selector_events.py", line 731, in _force_close
    self._loop.call_soon(self._call_connection_lost, exc)
  File "/home/buildbot/buildarea/3.10.cstratak-RHEL8-ppc64le.lto/build/Lib/asyncio/base_events.py", line 745, in call_soon
    self._check_closed()
  File "/home/buildbot/buildarea/3.10.cstratak-RHEL8-ppc64le.lto/build/Lib/asyncio/base_events.py", line 510, in _check_closed
    raise RuntimeError('Event loop is closed')
RuntimeError: Event loop is closed

asyncio ssl implementation has been rewritten with bpo-44011: This is outdated now and should be closed @vstinner.

I didn't see this issue recently, I close the issue.