Thread 1 (Thread 47378426343632 (LWP 16002)):
#0  0x00002b1725884738 in __lll_mutex_lock_wait () from /lib/libpthread.so.0
#1  0x00002b1725880901 in _L_mutex_lock_100 () from /lib/libpthread.so.0
#2  0x00002b17258802a5 in __pthread_mutex_lock (mutex=0xa91cf0) at pthread_mutex_lock.c:81
#3  0x00002aaaad17211a in gst_object_get_parent (object=0x126d260) at gstobject.c:841
#4  0x00002aaaad172848 in gst_object_get_path_string (object=0x126d260) at gstobject.c:1086
#5  0x00002aaaac69bf5f in _wrap_gst_object_tp_str (self=0x1106b40) at gstobject.override:66
#6  0x00002b172558bc82 in _PyObject_Str (v=0xa91cf0) at Objects/object.c:406
#7  0x00002b1725597514 in PyString_Format (format=0x1037d50, args=0x10207a0) at Objects/stringobject.c:4653
#8  0x00002b172555e2ce in binary_op1 (v=0x2aaab40ec710, w=0x0, op_slot=32) at Objects/abstract.c:398
#9  0x00002b172555ed81 in binary_op (v=0xa91cf0, w=0x0, op_slot=629701136, op_name=0xffffffffffffffff <Address 0xffffffffffffffff out of bounds>)
    at Objects/abstract.c:450
#10 0x00002b17255cb746 in PyEval_EvalFrameEx (f=0x1379960, throwflag=<value optimized out>) at Python/ceval.c:1115
#11 0x00002b17255d0d26 in PyEval_EvalCodeEx (co=0x10a88a0, globals=<value optimized out>, locals=<value optimized out>, args=0x10bc118, argcount=4, kws=0x0, kwcount=0, 
---Type <return> to continue, or q <return> to quit---
    defs=0x0, defcount=0, closure=0x0) at Python/ceval.c:2831
#12 0x00002b1725578b2f in function_call (func=0x10b2758, arg=0x10bc100, kw=0x0) at Objects/funcobject.c:517
#13 0x00002b172555c0e3 in PyObject_Call (func=0xa91cf0, arg=0x0, kw=0x2b1725887a10) at Objects/abstract.c:1860
#14 0x00002b17255630bb in instancemethod_call (func=0x10b2758, arg=0x10bc100, kw=0x0) at Objects/classobject.c:2497
#15 0x00002b172555c0e3 in PyObject_Call (func=0xa91cf0, arg=0x0, kw=0x2b1725887a10) at Objects/abstract.c:1860
#16 0x00002b17255c962d in PyEval_CallObjectWithKeywords (func=0x101c4b0, arg=0x10f95a0, kw=0x0) at Python/ceval.c:3433
#17 0x00002b1726c9a127 in pyg_closure_marshal (closure=0x138d020, return_value=0x0, n_param_values=2, param_values=0x7fff857a5950, invocation_hint=<value optimized out>, 
    marshal_data=<value optimized out>) at pygtype.c:1129
#18 0x00002b1726ed6c9e in IA__g_closure_invoke (closure=0x138d020, return_value=0x0, n_param_values=2, param_values=0x7fff857a5950, invocation_hint=0x7fff857a5830)
    at gclosure.c:490
#19 0x00002b1726eea920 in signal_emit_unlocked_R (node=0x105e2f0, detail=671, instance=0x1619190, emission_return=0x0, instance_and_params=0x7fff857a5950)