[PyKDE] pyqt/mysqld thread deadlock

["Martin v. Löwis"]

Kaleb Pederson wrote:
> (gdb) thread 1
> #0  0x4024b1be in select () from /lib/libc.so.6
[...]
> #16 0x080a81d2 in PyImport_ImportModuleEx (name=0x818a924 "gem.src.gui.gui", 
> globals=0x8145154, locals=0x8145154, fromlist=0x8114484) at 
> Python/import.c:1658
[...]
>>From my limited knowledge of the Python interpreter, it looks like the lock 
> only gets acquired once in the third thread.  In which case, there would be 
> no reason for it to block.  But, the first thread also had some relevant 
> import calls, so I'm not sure.  Where do I look now?

See the source of PyImport_ImportModuleEx. It acquires the import lock, 
so you are holding the import lock while QApplication_exec_loop is 
running. That means you deadlock.

gem.src.gui.gui should not run the mainloop, but expose a function to 
run the mainloop, which the importer of gui should then invoke.

Regards,
Martin