Python-psycopg2 double free or corruption with threading

[yassineaboukir]

Hi,

It looks like issue #384 is still reproducible running a multithreaded Python script. My testing environment is the following:

Name: psycopg2-binary
Version: 2.7.7

Distributor ID:	Ubuntu
Description:	Ubuntu 16.04.3 LTS
Release:	16.04
Codename:	xenial

python2.7

Error Stack Trace:

*** Error in `/usr/bin/python': double free or corruption (!prev): 0x00007f970000a850 ***
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x777e5)[0x7f97139b27e5]
/lib/x86_64-linux-gnu/libc.so.6(+0x8037a)[0x7f97139bb37a]
/lib/x86_64-linux-gnu/libc.so.6(+0x83350)[0x7f97139be350]
/lib/x86_64-linux-gnu/libc.so.6(realloc+0x179)[0x7f97139bf839]
/usr/local/lib/python2.7/dist-packages/psycopg2/.libs/./libcrypto-c1fa9491.so.1.0.2q(CRYPTO_realloc+0x49)[0x7f970fbcd289]
/usr/local/lib/python2.7/dist-packages/psycopg2/.libs/./libcrypto-c1fa9491.so.1.0.2q(lh_insert+0x18f)[0x7f970fc80a2f]
/usr/local/lib/python2.7/dist-packages/psycopg2/.libs/./libcrypto-c1fa9491.so.1.0.2q(+0x1205f0)[0x7f970fc835f0]
/usr/local/lib/python2.7/dist-packages/psycopg2/.libs/./libcrypto-c1fa9491.so.1.0.2q(ERR_get_state+0x196)[0x7f970fc84536]
/usr/local/lib/python2.7/dist-packages/psycopg2/.libs/./libcrypto-c1fa9491.so.1.0.2q(ERR_clear_error+0xf)[0x7f970fc8482f]
/usr/local/lib/python2.7/dist-packages/psycopg2/.libs/libpq-bd31fe2b.so.5.11(+0x24ec1)[0x7f97102a7ec1]
/usr/local/lib/python2.7/dist-packages/psycopg2/.libs/libpq-bd31fe2b.so.5.11(PQconnectPoll+0xb78)[0x7f9710291ba8]
/usr/local/lib/python2.7/dist-packages/psycopg2/.libs/libpq-bd31fe2b.so.5.11(+0xfa28)[0x7f9710292a28]
/usr/local/lib/python2.7/dist-packages/psycopg2/.libs/libpq-bd31fe2b.so.5.11(PQconnectdb+0x1f)[0x7f971029541f]
/usr/local/lib/python2.7/dist-packages/psycopg2/_psycopg.so(+0x129c1)[0x7f97104e69c1]
/usr/local/lib/python2.7/dist-packages/psycopg2/_psycopg.so(+0x1374f)[0x7f97104e774f]
/usr/bin/python[0x4aaafb]
/usr/bin/python(PyObject_Call+0x3e)[0x4a587e]
/usr/bin/python(_PyObject_CallFunction_SizeT+0xfc)[0x52be9c]
/usr/local/lib/python2.7/dist-packages/psycopg2/_psycopg.so(+0xc268)[0x7f97104e0268]
/usr/bin/python(PyEval_EvalFrameEx+0x6f3e)[0x4c2e1e]
/usr/bin/python(PyEval_EvalCodeEx+0x306)[0x4b9b66]
/usr/bin/python(PyEval_EvalFrameEx+0x58e6)[0x4c17c6]
/usr/bin/python(PyEval_EvalCodeEx+0x306)[0x4b9b66]
/usr/bin/python(PyEval_EvalFrameEx+0x58e6)[0x4c17c6]
/usr/bin/python(PyEval_EvalCodeEx+0x306)[0x4b9b66]
/usr/bin/python[0x4d57a3]
/usr/bin/python(PyObject_Call+0x3e)[0x4a587e]
/usr/bin/python(PyEval_EvalFrameEx+0x263e)[0x4be51e]
/usr/bin/python(PyEval_EvalFrameEx+0x553f)[0x4c141f]
/usr/bin/python(PyEval_EvalFrameEx+0x553f)[0x4c141f]
/usr/bin/python(PyEval_EvalCodeEx+0x306)[0x4b9b66]
/usr/bin/python[0x4d5669]
/usr/bin/python[0x4eef5e]
/usr/bin/python(PyObject_Call+0x3e)[0x4a587e]
/usr/bin/python(PyEval_CallObjectWithKeywords+0x30)[0x4c5ef0]
/usr/bin/python[0x589662]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x76ba)[0x7f9713d0c6ba]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f9713a4241d]
======= Memory map: ========
00400000-006de000 r-xp 00000000 fd:01 27812                              /usr/bin/python2.7

Any idea what might be causing this issue?

[dvarrazzo]

No, this is not a case of #384, rather it is a manifestation of #543: the problem happens on connect with OpenSSL 1.0.2 and the binary packages.

I am just about to release psycopg 2.8.2 whose binary packages are built with OpenSSL 1.1 (see psycopg/psycopg2-wheels#8), it would be great if you could test with it.

I would also be really grateful if you could provide a test to reproduce the issue: I'm quite burnt out by the problems with the binary packages and I would really like to have a proof of the quality of OpenSSL 1.1 before endorsing them again.

I'll use this issue as a chance to thank again @matthew-brett and @jerickso for putting together the 1.1 build: amazing job :)