Hi all, It seems that, there is a memory leak bug in libvirt_virConnectDomainEventJobCompletedCallback() function of libvirt-override.c. We didn't decrease the reference of 'pyobj_dict' in this function or any other places while pyt0bj_ret is not zero. libvirt_virConnectDomainEventJobCompletedCallback() { ... ... pyobj_ret = PyObject_CallMethod(pyobj_conn, (char*)"_dispatchDomainEventJobCompletedCallback", (char*)"OOO", pyobj_dom, pyobj_dict, pyobj_cbData); Py_DECREF(pyobj_cbData); Py_DECREF(pyobj_dom); cleanup: if (!pyobj_ret) { DEBUG("%s - ret:%p\n", __FUNCTION__, pyobj_ret); PyErr_Print(); Py_XDECREF(pyobj_dict); } else { Py_DECREF(pyobj_ret); ret = 0; } LIBVIRT_RELEASE_THREAD_STATE; return ret; } I don't think the reference of pyobj_dict will be stolen by PyObject_CallMethod when it is passed to the Python function _dispatchDomainEventJobCompletedCallback. In fact, we have a test which triggered lots of events and found that the memory of the test process will keep raising slowly and could not be reclaimed even we called gc.collect() explicitly in our codes. So, is it a bug ? Any comments ?