Hi,

sometimes (but not reliably reproducibly, one has to run it a few times) I get a segmentation fault when running the following networkx based Python code on large input graphs: https://gitlab.mister-muffin.de/debian-bootstrap/botch/blob/master/tools/graph-difference.py

I'm running Debian unstable with the python3.4 package of version 3.4.3-7 on architecture amd64.

The core dump is 1GB large so I'm just attaching the traceback from gdb.

The string "hscolour:amd64 (= 1.20.3-2)" that you see in the traceback is one of the vertex attributes in the input graph.

What else do you need to debug the problem?

#0  asciilib_split_char.lto_priv () at ../Objects/stringlib/split.h:126
#1  0x000000000058e65a in asciilib_split (maxcount=<optimized out>, sep_len=1, sep=0x7f1b3088dfb0 ",", str_len=27, 
    str=0x7f1b230abfb0 "hscolour:amd64 (= 1.20.3-2)", str_obj='hscolour:amd64 (= 1.20.3-2)') at ../Objects/stringlib/split.h:158
#2  split (maxcount=<optimized out>, substring=',', self='hscolour:amd64 (= 1.20.3-2)') at ../Objects/unicodeobject.c:10099
#3  unicode_split.lto_priv () at ../Objects/unicodeobject.c:12639
#4  0x000000000050d8fe in call_function (oparg=<optimized out>, pp_stack=0x7ffdf1a8ed80) at ../Python/ceval.c:4237
#5  PyEval_EvalFrameEx () at ../Python/ceval.c:2838
#6  0x00000000005ab095 in PyEval_EvalCodeEx () at ../Python/ceval.c:3588
#7  0x000000000051163d in fast_function (nk=<optimized out>, na=<optimized out>, n=<optimized out>, pp_stack=0x7ffdf1a8ef60, 
    func=<optimized out>) at ../Python/ceval.c:4344
#8  call_function (oparg=<optimized out>, pp_stack=0x7ffdf1a8ef60) at ../Python/ceval.c:4262
#9  PyEval_EvalFrameEx () at ../Python/ceval.c:2838
#10 0x00000000005ab095 in PyEval_EvalCodeEx () at ../Python/ceval.c:3588
#11 0x000000000051163d in fast_function (nk=<optimized out>, na=<optimized out>, n=<optimized out>, pp_stack=0x7ffdf1a8f140, 
    func=<optimized out>) at ../Python/ceval.c:4344
#12 call_function (oparg=<optimized out>, pp_stack=0x7ffdf1a8f140) at ../Python/ceval.c:4262
#13 PyEval_EvalFrameEx () at ../Python/ceval.c:2838
#14 0x00000000005ab095 in PyEval_EvalCodeEx () at ../Python/ceval.c:3588
#15 0x000000000051163d in fast_function (nk=<optimized out>, na=<optimized out>, n=<optimized out>, pp_stack=0x7ffdf1a8f320, 
    func=<optimized out>) at ../Python/ceval.c:4344
#16 call_function (oparg=<optimized out>, pp_stack=0x7ffdf1a8f320) at ../Python/ceval.c:4262
#17 PyEval_EvalFrameEx () at ../Python/ceval.c:2838
#18 0x00000000005ab095 in PyEval_EvalCodeEx () at ../Python/ceval.c:3588
#19 0x00000000005e16a5 in PyEval_EvalCode (
    locals={'__package__': None, '__doc__': None, '__spec__': None, 'sys': <module at remote 0x7f1b309120e8>, 'graph_difference': <function at remote 0x7f1b308ddc80>, '__file__': './tools/graph-difference.py', '__builtins__': <module at remote 0x7f1b31cd2c28>, 'parser': <ArgumentParser(_action_groups=[<_ArgumentGroup(_action_groups=[], _has_negative_number_optionals=[], prefix_chars='-', description=None, _defaults={}, _negative_number_matcher=<_sre.SRE_Pattern at remote 0x7f1b2e002d98>, _registries={'action': {'append': <type at remote 0x2d57a58>, 'store_true': <type at remote 0x2d548a8>, 'store_false': <type at remote 0x2d54da8>, 'help': <type at remote 0x2d58688>, 'count': <type at remote 0x2d58278>, 'append_const': <type at remote 0x2d57e68>, 'store': <type at remote 0x2ded3b8>, None: <type at remote 0x2ded3b8>, 'store_const': <type at remote 0x2d54498>, 'version': <type at remote 0x2d58bb8>, 'parsers': <type at remote 0x2d5df78>}, 'type': {None: <function at remote 0x7f1b2d1f86a8>}}, _group_actions=[<_StoreAction(d...(truncated), 
    globals={'__package__': None, '__doc__': None, '__spec__': None, 'sys': <module at remote 0x7f1b309120e8>, 'graph_difference': <function at remote 0x7f1b308ddc80>, '__file__': './tools/graph-difference.py', '__builtins__': <module at remote 0x7f1b31cd2c28>, 'parser': <ArgumentParser(_action_groups=[<_ArgumentGroup(_action_groups=[], _has_negative_number_optionals=[], prefix_chars='-', description=None, _defaults={}, _negative_number_matcher=<_sre.SRE_Pattern at remote 0x7f1b2e002d98>, _registries={'action': {'append': <type at remote 0x2d57a58>, 'store_true': <type at remote 0x2d548a8>, 'store_false': <type at remote 0x2d54da8>, 'help': <type at remote 0x2d58688>, 'count': <type at remote 0x2d58278>, 'append_const': <type at remote 0x2d57e68>, 'store': <type at remote 0x2ded3b8>, None: <type at remote 0x2ded3b8>, 'store_const': <type at remote 0x2d54498>, 'version': <type at remote 0x2d58bb8>, 'parsers': <type at remote 0x2d5df78>}, 'type': {None: <function at remote 0x7f1b2d1f86a8>}}, _group_actions=[<_StoreAction(d...(truncated), co=<code at remote 0x7f1b307f09c0>) at ../Python/ceval.c:775
#20 run_mod () at ../Python/pythonrun.c:2180
#21 0x00000000005e176a in PyRun_FileExFlags () at ../Python/pythonrun.c:2133
#22 0x00000000005e237a in PyRun_SimpleFileExFlags () at ../Python/pythonrun.c:1606
#23 0x00000000005fdb60 in run_file (p_cf=<optimized out>, filename=<optimized out>, fp=<optimized out>) at ../Modules/main.c:319
#24 Py_Main () at ../Modules/main.c:751
#25 0x00000000004c234f in main () at ../Modules/python.c:69
#26 0x00007f1b30972b45 in __libc_start_main () from /lib/x86_64-linux-gnu/libc.so.6
#27 0x00000000005ba765 in _start ()