STINNER Victor added the comment:
I ran test_asyncio on my own FreeBSD VM, with the sandbox/issue21645 repository
and I got a new (different) error on signal handling: RuntimeError('reentrant
call inside') when writing into sys.stderr. To be fair: this bug was introduced
by my changes in this repository adding debug traces ("logger.error("handle
signal %s" % sig)").
IMO the Py_AddPendingCall() function in Python is dangerous: the callback
should be "signal-safe" but this concept is not defined Python. In the C
language, there is a strict list of allowed functions, in Python it's unclear:
the reentrant call is just an example. It's probably easy to deadlock if you
call the "wrong" function".
Py_AddPendingCall() injects arbitrary Python code between *any* other Python
bytecode, it's like the evil greenlet with greenthreads.
That's why I consider that it would be safer to call _handle_signal() from the
event loop, not using Py_AddPendingCall():
https://code.google.com/p/tulip/issues/detail?id=192
Output of the new bug on FreeBSD:
-----------
[1085] C signal_handler: sig_num=20, thread=34380739584
C signal_handler: trip signal (tripped=0)
[1085] trip_signal(20)
trip_signal(20); write()
trip_signal(20); write() -> 1
[1085] Py_AddPendingCall(checksignals_witharg), thread=34380739584
--- Logging error ---
Traceback (most recent call last):
File "/usr/home/haypo/prog/python/default/Lib/logging/__init__.py", line 980,
in emit
stream.write(self.terminator)
RuntimeError: reentrant call inside <_io.BufferedWriter name='<stderr>'>
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/home/haypo/prog/python/default/Lib/logging/__init__.py", line 980,
in emit
stream.write(self.terminator)
File "/usr/home/haypo/prog/python/default/Lib/asyncio/unix_events.py", line
95, in _handle_signal
logger.error("handle signal %s" % sig)
File "/usr/home/haypo/prog/python/default/Lib/logging/__init__.py", line
1302, in error
self._log(ERROR, msg, args, **kwargs)
File "/usr/home/haypo/prog/python/default/Lib/logging/__init__.py", line
1408, in _log
self.handle(record)
File "/usr/home/haypo/prog/python/default/Lib/logging/__init__.py", line
1418, in handle
self.callHandlers(record)
File "/usr/home/haypo/prog/python/default/Lib/logging/__init__.py", line
1480, in callHandlers
hdlr.handle(record)
File "/usr/home/haypo/prog/python/default/Lib/logging/__init__.py", line 852,
in handle
self.emit(record)
File "/usr/home/haypo/prog/python/default/Lib/logging/__init__.py", line 983,
in emit
self.handleError(record)
File "/usr/home/haypo/prog/python/default/Lib/logging/__init__.py", line 904,
in handleError
sys.stderr.write('--- Logging error ---\n')
RuntimeError: reentrant call inside <_io.BufferedWriter name='<stderr>'>
Call stack:
File "/usr/home/haypo/prog/python/default/Lib/runpy.py", line 170, in
_run_module_as_main
"__main__", mod_spec)
File "/usr/home/haypo/prog/python/default/Lib/runpy.py", line 85, in _run_code
exec(code, run_globals)
File "/usr/home/haypo/prog/python/default/Lib/test/__main__.py", line 3, in
<module>
regrtest.main_in_temp_cwd()
File "/usr/home/haypo/prog/python/default/Lib/test/regrtest.py", line 1562,
in main_in_temp_cwd
main()
File "/usr/home/haypo/prog/python/default/Lib/test/regrtest.py", line 763, in
main
match_tests=ns.match_tests)
File "/usr/home/haypo/prog/python/default/Lib/test/regrtest.py", line 978, in
runtest
display_failure=not verbose)
File "/usr/home/haypo/prog/python/default/Lib/test/regrtest.py", line 1278,
in runtest_inner
test_runner()
File "/usr/home/haypo/prog/python/default/Lib/test/test_asyncio/__init__.py",
line 29, in test_main
run_unittest(suite())
File "/usr/home/haypo/prog/python/default/Lib/test/support/__init__.py", line
1758, in run_unittest
_run_suite(suite)
File "/usr/home/haypo/prog/python/default/Lib/test/support/__init__.py", line
1724, in _run_suite
result = runner.run(suite)
File "/usr/home/haypo/prog/python/default/Lib/unittest/runner.py", line 168,
in run
test(result)
File "/usr/home/haypo/prog/python/default/Lib/unittest/suite.py", line 87, in
__call__
return self.run(*args, **kwds)
File "/usr/home/haypo/prog/python/default/Lib/unittest/suite.py", line 125,
in run
test(result)
File "/usr/home/haypo/prog/python/default/Lib/unittest/suite.py", line 87, in
__call__
return self.run(*args, **kwds)
File "/usr/home/haypo/prog/python/default/Lib/unittest/suite.py", line 125,
in run
test(result)
File "/usr/home/haypo/prog/python/default/Lib/unittest/suite.py", line 87, in
__call__
return self.run(*args, **kwds)
File "/usr/home/haypo/prog/python/default/Lib/unittest/suite.py", line 125,
in run
test(result)
File "/usr/home/haypo/prog/python/default/Lib/unittest/case.py", line 625, in
__call__
return self.run(*args, **kwds)
File "/usr/home/haypo/prog/python/default/Lib/unittest/case.py", line 577, in
run
testMethod()
File
"/usr/home/haypo/prog/python/default/Lib/test/test_asyncio/test_streams.py",
line 647, in test_read_all_from_pipe_reader
self.loop.run_until_complete(proc.wait())
File "/usr/home/haypo/prog/python/default/Lib/asyncio/base_events.py", line
265, in run_until_complete
self.run_forever()
File "/usr/home/haypo/prog/python/default/Lib/asyncio/base_events.py", line
238, in run_forever
self._run_once()
File "/usr/home/haypo/prog/python/default/Lib/asyncio/base_events.py", line
984, in _run_once
logger.error("[pid %s] _run_once: thread=%s" % (os.getpid(),
threading.get_ident()))
Message: '[pid 1085] _run_once: thread=34380739584'
-----------
----------
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<http://bugs.python.org/issue21645>
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