On 2015-05-21 15:55, Eric Snow wrote:
(see http://bugs.python.org/issue16991)
I an working on resolving an intermittent segfault that my C
OrderedDict patch introduces. The failure happens in
test_configparser (RawConfigParser uses OrderedDict internally), but
only sporadically. However, Ned pointed out to me that it appears to
be related to hash randomization, which I have verified. I'm looking
into it.
In the meantime, here's a specific question. What would lead to the
pattern of failures I'm seeing? I've verified that the segfault
happens consistently for certain hash randomization seeds and never
for the rest. I don't immediately recognize the pattern but expect
that it would shed some light on where the problem lies. I ran the
following command with the OrderedDict patch applied:
for i in `seq 1 100`; do echo $i; PYTHONHASHSEED=$i ./python -m
test.regrtest -m test_basic test_configparser ; done
Through 100 I get segfaults with seeds of 7, 15, 35, 37, 39, 40, 42,
47, 50, 66, 67, 85, 87, 88, and 92. I expect the distribution across
all seeds is uniform, but I haven't verified that.
Thoughts?
In "_odict_get_index", for example (there are others), you're caching
"ma_keys":
PyDictKeysObject *keys = ((PyDictObject *)od)->ma_keys;
If it resizes, you go back to the label "start", which is after that
line, but could "ma_keys" change when it's resized?
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