Application that crashed: plasmoidviewer Version of the application: 1.0 KDE Version: 4.3.4 (KDE 4.3.4) Qt Version: 4.5.2 Operating System: Linux 2.6.31-16-generic i686 Distribution: Ubuntu 9.10 What I was doing when the application crashed: In a python applet-plasmoid, I had some code calling KIO.NetAccess.download and emitting some (arbitrary) signals when done, which was working fine. I put this code in a QThread to make it work asynchronously, and now the applet crashes the entire plasma-desktop on exit. Note that the plasmoid does complete all tasks, including secondary-threaded ones; it crashes only on exit. The QThread job is launched from the applet "init" method (not "__init__"). PyKDE documentation advises about such cases as a result of not subclassing KMainWindow, but this is not possible for plasmoids. I'm on Kubuntu 9.10 with ptyhon-kde4-dbg, python-qt4-dbg, kdelibs5-dbg, let me know if I need to reproduce with other packages installed. -- Backtrace: Application: Plasma Widget Viewer (plasmoidviewer), signal: Segmentation fault [Current thread is 1 (Thread 0xb772d710 (LWP 3791))] Thread 2 (Thread 0xaafb6b70 (LWP 3796)): #0 0x00dbf422 in __kernel_vsyscall () #1 0x0184f142 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0 #2 0x01f167e4 in pthread_cond_timedwait () from /lib/tls/i686/cmov/libc.so.6 #3 0x00a8adef in QWaitConditionPrivate::wait (this=0x9453ba0, mutex=0x9453b9c, time=30000) at thread/qwaitcondition_unix.cpp:85 #4 QWaitCondition::wait (this=0x9453ba0, mutex=0x9453b9c, time=30000) at thread/qwaitcondition_unix.cpp:159 #5 0x00a7f9ae in QThreadPoolThread::run (this=0x93b6520) at concurrent/qthreadpool.cpp:140 #6 0x00a89e32 in QThreadPrivate::start (arg=0x93b6520) at thread/qthread_unix.cpp:188 #7 0x0184a80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #8 0x01f097ee in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 1 (Thread 0xb772d710 (LWP 3791)): [KCrash Handler] #6 0x0211492a in PySys_GetObject (name=0x218653b "exitfunc") at ../Python/sysmodule.c:53 #7 0x0210ebd6 in call_sys_exitfunc () at ../Python/pythonrun.c:1681 #8 Py_Finalize () at ../Python/pythonrun.c:399 #9 0x01b66200 in KPythonPluginFactoryCleanup_PostRoutine () at ../../../../python/pykde4/kpythonpluginfactory/kpythonpluginfactory.cpp:67 #10 0x00b7ac00 in qt_call_post_routines () at kernel/qcoreapplication.cpp:163 #11 0x00ee9ba8 in ~QApplication (this=0xbfe9b2cc, __in_chrg=<value optimized out>) at kernel/qapplication.cpp:971 #12 0x00399a9a in ~KApplication (this=0xbfe9b2cc, __in_chrg=<value optimized out>) at ../../kdeui/kernel/kapplication.cpp:904 #13 0x0804f99d in _start () Reported using DrKonqi
Offtopic detail: KIO functions shouldn't be used with Threads... (as it can cause problems AFAIK). You should use the SIGNAL-SLOTS method. This could be a problem in bindings too. Regards
I tried removing the KIO calls and I still got a crash. I'll try to reduce the scope further...
The culprit was a call to time.sleep(1) in the secondary thread. Guess I just verified the old assumption that mixing QThreads and python threads is not a good idea.
I have a very similar problem with my plasmoid : #5 0x00007f5d50dcdc3d in PySys_GetObject (name=0x7f5d50e3d377 "exitfunc") at ../Python/sysmodule.c:53 I can remove the applet from plasmoidviewer (or plasma-desktop) without a problem, but when plasmoidviewer or plasma-desktop exits I get the crash. If you have any hint/idea please help me - I already spent hours on that.. What I do in the code: 1. load a library via ctypes (pulseaudio library) 2. install a callback function (to get notified by state-changes of pulseaudio) 3. start an external thread that "runs inside the library" OnExit: I stop that external thread and do the required cleanup - When I call sys.exit(0) inside my code plasmoidviewer exits without a crash (bot I don't want plasma-desktop to exit when I remove the plasmoid). - When I do not set a callback function, I get no crash --- Is this a threading problem? Maybe ctypes starts a thread for the callback function? Whats the relation between PySys_GetObject("exitfunc") and threads? the plasmoid: http://www.kde-look.org/content/show.php/?content=116676
Could be related to this python-bug: http://bugs.python.org/issue6869
*** Bug 221049 has been marked as a duplicate of this bug. ***
*** Bug 248412 has been marked as a duplicate of this bug. ***
This crash report is at least 3 years old and there were no further comments or status updates since then. Therefore we believe that this crash is already fixed in recent KDE 4 versions or the backtrace is no longer applicable to the current KDE 4 sources. If the crash still happens with a recent KDE version (4.10.5 or 4.11), please add an updated backtrace or provide steps to reproduce. For more information, see http://techbase.kde.org/Development/Tutorials/Debugging/How_to_create_useful_crash_reports (To prevent automatic closing of this bug in the future, please set the bug status to ASSIGNED or CONFIRMED)
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Dear Bug Submitter, This bug has been in NEEDSINFO status with no change for at least 30 days. The bug is now closed as RESOLVED > WORKSFORME due to lack of needed information. For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging Thank you for helping us make KDE software even better for everyone!