Hi Christoph,
Thank you very much for reporting this bug to us. It would be of tremendous
help if you could provide a minimal reproduceable example so we can try to
reproduce the issue ourselves and debug. Also, please do not hesitate to open a
bug report, that makes it easier for us to keep track of all related
information and progress. :)
Best regards,
Adrian Herrmann
Software Engineer, Qt for Python
Qt Group
Erich-Thilo-Str. 10 12489
Berlin, Germany
adrian.herrm...@qt.io
+49 1578 0598682
www.qt.io
Geschäftsführer: Mika Pälsi, Juha Varelius, Jouni Lintunen Sitz der
Gesellschaft: Berlin, Registergericht: Amtsgericht Charlottenburg, HRB 144331 B
________________________________________
Von: PySide <pyside-boun...@qt-project.org> im Auftrag von ic...@gmx.net
<ic...@gmx.net>
Gesendet: Samstag, 17. Juni 2023 19:27
An: PySide@qt-project.org
Betreff: [PySide] Deadlocks during signal.disconnect
Hi,
I thought before opening a bug I'd ask this question here and see if I'm doing
something stupid... The problem occurs very rarely (maybe in one of 100 tries),
but it is reproducable in a larger application. Please forgive to not have a
stripped down test, maybe someone can already see what is happening from the
information given. If not, I'd probably have to reproduce the issue in a
smaller test case.
It seems that the signal.disconnect deadlocks sometimes.
There are two classes involved:
class MyFilter(ClassDerivingFromQObject):
# snip
def onOpen(self):
logger.info("onOpen start")
pb = Services.getService("PlaybackControl")
pb.sequenceOpened.connect(self.seqOpened)
logger.info("onOpen stop")
def onClose(self):
logger.info("onClose start")
pb = Services.getService("PlaybackControl") # pb is a QSharedPointer to
a python class deriving from QObject (the project uses shiboken)
s = pb.sequenceOpened
s.disconnect(self.seqOpened) # this call deadlocks
logger.info("onClose stop")
def seqOpened(self, *args):
logger.info("seqOpened")
And the other involved class
class GenericReader(AnotherClassDerivingFromQObject):
# snip
def onClose(self):
pb = Services.getService("PlaybackControl") # pb is a QSharedPointer to
a python class deriving from QObject (the project uses shiboken)
pb.removeConnections(self) # this call deadlocks
I managed to get the python tracebacks using the very cool project py-spy:
Thread 197717 (idle): "Dummy-1"
onClose (myfilter.py:23)
_stateTransition (nexxT/core/FilterEnvironment.py:310)
close (nexxT/core/FilterEnvironment.py:366)
performOperation (nexxT/core/Thread.py:197)
run (nexxT/core/Thread.py:52)
Thread 197716 (idle)
onClose (nexxT/filters/GenericReader.py:361)
_stateTransition (nexxT/core/FilterEnvironment.py:310)
close (nexxT/core/FilterEnvironment.py:366)
performOperation (nexxT/core/Thread.py:197)
run (nexxT/core/Thread.py:52)
And the tracebacks from gdb of these threads are here:
Thread 10 (Thread 0x7f5aa4a8a6c0 (LWP 197717) "filter"):
#0 0x00007f5ac1dcf4f9 in syscall () from /lib/x86_64-linux-gnu/libc.so.6
#1 0x00007f5aab4cae95 in QBasicMutex::lockInternal() () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#2 0x00007f5aab38f2d5 in ?? () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#3 0x00007f5aab390307 in QMetaObject::disconnectOne(QObject const*, int,
QObject const*, int) () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#4 0x00007f5aac6af048 in PySide::qobjectDisconnectCallback(QObject*, char
const*, _object*) () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/libpyside6.abi3.so.6.4
#5 0x00007f5aabbd985b in ?? () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/QtCore.abi3.so
#6 0x0000000000547ac6 in ?? ()
#7 0x00000000005f7f50 in PyObject_CallObject ()
#8 0x00007f5aac6a489d in ?? () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/libpyside6.abi3.so.6.4
#9 0x00000000005230d0 in ?? ()
#10 0x000000000053ac2c in PyObject_Vectorcall ()
#11 0x000000000052b940 in _PyEval_EvalFrameDefault ()
#12 0x00000000005855a4 in ?? ()
#13 0x000000000058510e in ?? ()
#14 0x00007f5aac69d2f1 in
PySide::SignalManager::callPythonMetaMethod(QMetaMethod const&, void**,
_object*, bool) () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/libpyside6.abi3.so.6.4
#15 0x00007f5aac69d5d6 in
PySide::SignalManager::SignalManagerPrivate::qtMethodMetacall(QObject*, int,
void**) () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/libpyside6.abi3.so.6.4
#16 0x00007f5aab38937c in QObject::event(QEvent*) () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#17 0x00007f5aab33929a in QCoreApplication::notifyInternal2(QObject*, QEvent*)
() from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#18 0x00007f5aab33fdfd in QCoreApplicationPrivate::sendPostedEvents(QObject*,
int, QThreadData*) () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#19 0x00007f5aab5e11b3 in ?? () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#20 0x00007f5aab91c7a9 in g_main_context_dispatch () from
/lib/x86_64-linux-gnu/libglib-2.0.so.0
#21 0x00007f5aab91ca38 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#22 0x00007f5aab91cacc in g_main_context_iteration () from
/lib/x86_64-linux-gnu/libglib-2.0.so.0
#23 0x00007f5aab5e0b3a in
QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) ()
from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#24 0x00007f5aab344d5b in
QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#25 0x00007f5aab450eac in QThread::exec() () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#26 0x00007f5aabc729c0 in ?? () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/QtCore.abi3.so
#27 0x000000000051f567 in ?? ()
#28 0x000000000053ac2c in PyObject_Vectorcall ()
#29 0x000000000052b940 in _PyEval_EvalFrameDefault ()
#30 0x00000000005855a4 in ?? ()
#31 0x0000000000585148 in ?? ()
#32 0x00007f5aabc72915 in ?? () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/QtCore.abi3.so
#33 0x00007f5aab4cac7f in ?? () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#34 0x00007f5ac1d56fd4 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
#35 0x00007f5ac1dd75bc in ?? () from /lib/x86_64-linux-gnu/libc.so.6
Thread 9 (Thread 0x7f5a9c2896c0 (LWP 197716) "reader"):
#0 0x00007f5ac1d53d36 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
#1 0x00007f5ac1d566dc in pthread_cond_timedwait () from
/lib/x86_64-linux-gnu/libc.so.6
#2 0x00000000004f91da in ?? ()
#3 0x0000000000528bf2 in PyEval_RestoreThread ()
#4 0x000000000064dacc in PyGILState_Ensure ()
#5 0x00007f5ac141e16d in Shiboken::GilState::GilState() () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/shiboken6/libshiboken6.abi3.so.6.4
#6 0x00007f5ac08cae13 in FilterWrapper::disconnectNotify(QMetaMethod const&)
() from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/nexxT/binary/linux_x86_64/release/cnexxT.abi3.so
#7 0x00007f5aab39546a in QObject::~QObject() () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#8 0x00007f5aabbd6ae6 in ?? () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/QtCore.abi3.so
#9 0x00007f5ac141b93a in ?? () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/shiboken6/libshiboken6.abi3.so.6.4
#10 0x000000000058cedd in ?? ()
#11 0x0000000000515d7f in ?? ()
#12 0x000000000053fb3f in ?? ()
#13 0x000000000052b338 in _PyEval_EvalFrameDefault ()
#14 0x00000000005855a4 in ?? ()
#15 0x000000000058510e in ?? ()
#16 0x00007f5aac69d2f1 in
PySide::SignalManager::callPythonMetaMethod(QMetaMethod const&, void**,
_object*, bool) () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/libpyside6.abi3.so.6.4
#17 0x00007f5aac69d5d6 in
PySide::SignalManager::SignalManagerPrivate::qtMethodMetacall(QObject*, int,
void**) () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/libpyside6.abi3.so.6.4
#18 0x00007f5aab38937c in QObject::event(QEvent*) () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#19 0x00007f5aab33929a in QCoreApplication::notifyInternal2(QObject*, QEvent*)
() from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#20 0x00007f5aab33fdfd in QCoreApplicationPrivate::sendPostedEvents(QObject*,
int, QThreadData*) () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#21 0x00007f5aab5e11b3 in ?? () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#22 0x00007f5aab91c7a9 in g_main_context_dispatch () from
/lib/x86_64-linux-gnu/libglib-2.0.so.0
#23 0x00007f5aab91ca38 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#24 0x00007f5aab91cacc in g_main_context_iteration () from
/lib/x86_64-linux-gnu/libglib-2.0.so.0
#25 0x00007f5aab5e0b3a in
QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) ()
from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#26 0x00007f5aab344d5b in
QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#27 0x00007f5aab450eac in QThread::exec() () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#28 0x00007f5aabc729c0 in ?? () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/QtCore.abi3.so
#29 0x000000000051f567 in ?? ()
#30 0x000000000053ac2c in PyObject_Vectorcall ()
#31 0x000000000052b940 in _PyEval_EvalFrameDefault ()
#32 0x00000000005855a4 in ?? ()
#33 0x0000000000585148 in ?? ()
#34 0x00007f5aabc72915 in ?? () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/QtCore.abi3.so
#35 0x00007f5aab4cac7f in ?? () from
/home/wiedeman/develop/nexxT-deadlock/venv/lib/python3.11/site-packages/PySide6/Qt/lib/libQt6Core.so.6
#36 0x00007f5ac1d56fd4 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
#37 0x00007f5ac1dd75bc in ?? () from /lib/x86_64-linux-gnu/libc.so.6
Thank you for taking a look!
Kind Regards
Christoph
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