haypo@selma$ gdb -args ./python ~/bug.py 
(gdb) run
python: Objects/object.c:2453: _PyTrash_thread_deposit_object: Assertion `PyObject_IS_GC(op)' failed.

Program received signal SIGABRT, Aborted.

(gdb) py-bt
Traceback (most recent call first):
  File "/home/haypo/bug.py", line 130, in bench_parse
    root1 = etree.parse(xml_file).getroot()
  File "/home/haypo/bug.py", line 171, in bench_etree
    bench_func(etree, file_path, xml_data, xml_root)
  File "/home/haypo/bug.py", line 197, in <module>
    bench_etree(1, ET, bench_func)



(gdb) where
#0  0x00007ffff711892f in raise () from /lib64/libc.so.6
#1  0x00007ffff711a52a in abort () from /lib64/libc.so.6
#2  0x00007ffff7110e37 in __assert_fail_base () from /lib64/libc.so.6
#3  0x00007ffff7110ee2 in __assert_fail () from /lib64/libc.so.6
#4  0x0000000000463abe in _PyTrash_thread_deposit_object (op=<Element at remote 0x7fffec9152e0>) at Objects/object.c:2453
#5  0x00007fffecd29b17 in element_dealloc (self=0x7fffec9152e0) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:566
#6  0x000000000046346a in _Py_Dealloc (op=<Element at remote 0x7fffec9152e0>) at Objects/object.c:2262
#7  0x00007fffecd29058 in element_dealloc_extra (self=0x7fffec915280) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:301
#8  0x00007fffecd29abc in element_dealloc (self=0x7fffec915280) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:561
#9  0x000000000046346a in _Py_Dealloc (op=<Element at remote 0x7fffec915280>) at Objects/object.c:2262
#10 0x00007fffecd29058 in element_dealloc_extra (self=0x7fffec915220) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:301
#11 0x00007fffecd29abc in element_dealloc (self=0x7fffec915220) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:561
#12 0x000000000046346a in _Py_Dealloc (op=<Element at remote 0x7fffec915220>) at Objects/object.c:2262
#13 0x00007fffecd29058 in element_dealloc_extra (self=0x7fffec9151c0) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:301
#14 0x00007fffecd29abc in element_dealloc (self=0x7fffec9151c0) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:561
#15 0x000000000046346a in _Py_Dealloc (op=<Element at remote 0x7fffec9151c0>) at Objects/object.c:2262
#16 0x00007fffecd29058 in element_dealloc_extra (self=0x7fffec915160) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:301
#17 0x00007fffecd29abc in element_dealloc (self=0x7fffec915160) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:561
#18 0x000000000046346a in _Py_Dealloc (op=<Element at remote 0x7fffec915160>) at Objects/object.c:2262
#19 0x00007fffecd29058 in element_dealloc_extra (self=0x7fffec915100) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:301
#20 0x00007fffecd29abc in element_dealloc (self=0x7fffec915100) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:561
#21 0x000000000046346a in _Py_Dealloc (op=<Element at remote 0x7fffec915100>) at Objects/object.c:2262
#22 0x00007fffecd29058 in element_dealloc_extra (self=0x7fffec9150a0) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:301
#23 0x00007fffecd29abc in element_dealloc (self=0x7fffec9150a0) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:561
#24 0x000000000046346a in _Py_Dealloc (op=<Element at remote 0x7fffec9150a0>) at Objects/object.c:2262
#25 0x00007fffecd29058 in element_dealloc_extra (self=0x7fffec915040) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:301
#26 0x00007fffecd29abc in element_dealloc (self=0x7fffec915040) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:561
#27 0x000000000046346a in _Py_Dealloc (op=<Element at remote 0x7fffec915040>) at Objects/object.c:2262
#28 0x00007fffecd29058 in element_dealloc_extra (self=0x7fffec90ffa0) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:301
#29 0x00007fffecd29abc in element_dealloc (self=0x7fffec90ffa0) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:561
#30 0x000000000046346a in _Py_Dealloc (op=<Element at remote 0x7fffec90ffa0>) at Objects/object.c:2262
#31 0x00007fffecd29058 in element_dealloc_extra (self=0x7fffec90ff40) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:301
#32 0x00007fffecd29abc in element_dealloc (self=0x7fffec90ff40) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:561
#33 0x000000000046346a in _Py_Dealloc (op=<Element at remote 0x7fffec90ff40>) at Objects/object.c:2262
#34 0x00007fffecd29058 in element_dealloc_extra (self=0x7fffec90fee0) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:301
#35 0x00007fffecd29abc in element_dealloc (self=0x7fffec90fee0) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:561
#36 0x000000000046346a in _Py_Dealloc (op=<Element at remote 0x7fffec90fee0>) at Objects/object.c:2262
#37 0x00007fffecd29058 in element_dealloc_extra (self=0x7fffec90fe80) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:301
#38 0x00007fffecd29abc in element_dealloc (self=0x7fffec90fe80) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:561
#39 0x000000000046346a in _Py_Dealloc (op=<Element at remote 0x7fffec90fe80>) at Objects/object.c:2262
#40 0x00007fffecd29058 in element_dealloc_extra (self=0x7fffec90fe20) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:301
#41 0x00007fffecd29abc in element_dealloc (self=0x7fffec90fe20) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:561
#42 0x000000000046346a in _Py_Dealloc (op=<Element at remote 0x7fffec90fe20>) at Objects/object.c:2262
#43 0x00007fffecd29058 in element_dealloc_extra (self=0x7fffec90fdc0) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:301
#44 0x00007fffecd29abc in element_dealloc (self=0x7fffec90fdc0) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:561
#45 0x000000000046346a in _Py_Dealloc (op=<Element at remote 0x7fffec90fdc0>) at Objects/object.c:2262
#46 0x00007fffecd29058 in element_dealloc_extra (self=0x7fffec90fd60) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:301
#47 0x00007fffecd29abc in element_dealloc (self=0x7fffec90fd60) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:561
#48 0x000000000046346a in _Py_Dealloc (op=<Element at remote 0x7fffec90fd60>) at Objects/object.c:2262
#49 0x00007fffecd29058 in element_dealloc_extra (self=0x7fffec90fd00) at /home/haypo/prog/python/2.7/Modules/_elementtree.c:301
(...)