Issue 1:
Steps to reproduce: Run the following code

import numpy as np

n = 25
tmp1 = np.identity(n)
tmp2 = np.linalg.inv(tmp1)

print("Done")

Expected behaviour: Should finish running and print "Done"

Observed behaviour: About 8 times out of 10 the above code will hang on the np.linalg.inv line and python starts consuming ~100% CPU on one core. Python doesn't respond to Ctrl+C, and I have to kill the process through the task manager. If I change n <= 24, the code runs fine every time.

I've managed to reproduce this on Python 3.6.1 and 3.5.5 (see the below conda environment listings). In my Python 2.7 environment, I can't reproduce it.

Python 3.6 environment:

E:\Development>python
Python 3.6.1 |Continuum Analytics, Inc.| (default, May 11 2017, 13:25:24) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> exit()

E:\Development>conda list
# packages in environment at C:\Users\uqasnosw\AppData\Local\Continuum\Miniconda3:
#
# Name Version Build Channel
alabaster 0.7.10 py36_0
asn1crypto 0.22.0 py36_0
babel 2.4.0 py36_0
blas 1.1 openblas conda-forge
bzip2 1.0.6 vc14_1 [vc14] conda-forge
ca-certificates 2017.11.5 0 conda-forge
cffi 1.10.0 py36_0
clangdev 5.0.0 flang_3 [vc14 flang] conda-forge
colorama 0.3.9 py36_0
conda 4.5.2 py36_0 conda-forge
conda-env 2.6.0 0 conda-forge
console_shortcut 0.1.1 py36_1
cryptography 1.8.1 py36_0
cvxopt 1.2.0 py36_blas_openblas_200 [blas_openblas] conda-forge
cvxopt 1.1.9 <pip>
cycler 0.10.0 py36_0
dask-core 0.16.1 py_0 conda-forge
decorator 4.0.11 py36_0
decorator 4.2.1 <pip>
docutils 0.13.1 py36_0
freetype 2.8.1 vc14_0 [vc14] conda-forge
future 0.16.0 <pip>
glpk 4.65 vc14_0 [vc14] conda-forge
graphviz 2.38.0 4
gym 0.9.6 <pip>
icc_rt 2017.0.4 h97af966_0
icu 58.2 vc14_0 [vc14] conda-forge
idna 2.5 py36_0
imageio 2.2.0 py36_0 conda-forge
imagesize 0.7.1 py36_0
intel-openmp 2018.0.0 8
ipython 6.1.0 py36_0
ipython_genutils 0.2.0 py36_0
isort 4.2.15 <pip>
jedi 0.10.2 py36_2
jinja2 2.9.6 py36_0
jpeg 9b vc14_2 [vc14] conda-forge
kiwisolver 1.0.1 py36_1 conda-forge
lazy-object-proxy 1.3.1 <pip>
libflang 5.0.0 vc14_20180208 [vc14] conda-forge
libgpuarray 0.7.5 vc14_0 [vc14] conda-forge
libiconv 1.14 vc14_4 [vc14] conda-forge
libpng 1.6.34 vc14_0 [vc14] conda-forge
libpython 2.0 py36_0
libtiff 4.0.9 vc14_0 [vc14] conda-forge
libxml2 2.9.5 vc14_1 [vc14] conda-forge
llvm-meta 5.0.0 0 conda-forge
llvmdev 5.0.0 default_1 [vc14] conda-forge
m2w64-binutils 2.25.1 5
m2w64-bzip2 1.0.6 6
m2w64-crt-git 5.0.0.4636.2595836 2
m2w64-gcc 5.3.0 6
m2w64-gcc-ada 5.3.0 6
m2w64-gcc-fortran 5.3.0 6
m2w64-gcc-libgfortran 5.3.0 6
m2w64-gcc-libs 5.3.0 7
m2w64-gcc-libs-core 5.3.0 7
m2w64-gcc-objc 5.3.0 6
m2w64-gmp 6.1.0 2
m2w64-headers-git 5.0.0.4636.c0ad18a 2
m2w64-isl 0.16.1 2
m2w64-libiconv 1.14 6
m2w64-libmangle-git 5.0.0.4509.2e5a9a2 2
m2w64-libwinpthread-git 5.0.0.4634.697f757 2
m2w64-make 4.1.2351.a80a8b8 2
m2w64-mpc 1.0.3 3
m2w64-mpfr 3.1.4 4
m2w64-pkg-config 0.29.1 2
m2w64-toolchain 5.3.0 7
m2w64-tools-git 5.0.0.4592.90b8472 2
m2w64-windows-default-manifest 6.4 3
m2w64-winpthreads-git 5.0.0.4634.697f757 2
m2w64-zlib 1.2.8 10
mako 1.0.6 py36_0
markupsafe 0.23 py36_2
matplotlib 2.2.2 py36_1 conda-forge
matplotlib 2.1.2 <pip>
mccabe 0.6.1 <pip>
menuinst 1.4.7 py36_0
metis 5.1.0 vc14_3 [vc14] conda-forge
mingw 4.7 1
mkl 2018.0.2 1
mkl-service 1.1.2 py36_3
mkl_fft 1.0.1 py36_1 conda-forge
mkl_random 1.0.1 py36_0 conda-forge
msys2-conda-epoch 20160418 1
networkx 2.1 <pip>
networkx 2.0 py36_1 conda-forge
nose 1.3.7 py36_1
nose-parameterized 0.5.0 py36_0
numpy 1.14.0 <pip>
numpy 1.14.3 py36_blas_openblas_200 [blas_openblas] conda-forge
olefile 0.44 py36_0 conda-forge
openblas 0.2.20 vc14_7 [vc14] conda-forge
opencv-python 3.4.0 <pip>
openmp 5.0.0 vc14_1 [vc14] conda-forge
openssl 1.0.2n vc14_0 [vc14] conda-forge
packaging 16.8 py36_0
pandas 0.22.0 py36_1 conda-forge
path.py 10.3.1 py36_0
pickleshare 0.7.4 py36_0
Pillow 5.0.0 <pip>
pillow 5.0.0 py36_0 conda-forge
pip 9.0.3 py36_0 conda-forge
prompt_toolkit 1.0.14 py36_0
pyasn1 0.2.3 py36_0
pycosat 0.6.2 py36_0
pycparser 2.17 py36_0
pydot 1.0.29 <pip>
pyglet 1.3.1 <pip>
pygments 2.2.0 py36_0
pygpu 0.7.5 py36_0 conda-forge
pyopenssl 17.0.0 py36_0
pyparsing 2.2.0 <pip>
pyparsing 2.1.4 py36_0
pyqt 5.6.0 py36_2
python 3.6.1 2
python-dateutil 2.6.0 py36_0
python-dateutil 2.6.1 <pip>
pytz 2018.3 <pip>
pytz 2017.2 py36_0
PyWavelets 0.5.2 <pip>
pywavelets 0.5.2 py36_1 conda-forge
pywin32 220 py36_2
qt 5.6.2 vc14_1 [vc14] conda-forge
requests 2.14.2 py36_0
ruamel_yaml 0.11.14 py36_1
scikit-image 0.13.1 py36_0 conda-forge
scikit-learn 0.19.1 <pip>
scipy 1.0.0 py36h1260518_0
setuptools 27.2.0 py36_1
simplegeneric 0.8.1 py36_1
sip 4.18 py36_0
six 1.10.0 py36_0
six 1.11.0 <pip>
sklearn 0.0 <pip>
snowballstemmer 1.2.1 py36_0
sphinx 1.6.2 py36_0
sphinxcontrib 1.0 py36_0
sphinxcontrib-websupport 1.0.1 py36_0
sqlite 3.22.0 vc14_0 [vc14] conda-forge
suitesparse 5.1.2 blas_openblas_vc14_202 [blas_openblas vc14] conda-forge
tbb 2018_20171205 vc14_0 [vc14] conda-forge
theano 0.9.0 py36_0
tk 8.5.19 vc14_1 [vc14] conda-forge
toolz 0.8.2 py_2 conda-forge
tornado 5.0.2 py36_0 conda-forge
traitlets 4.3.2 py36_0
vc 14 0 conda-forge
vs2015_runtime 14.0.25123 0
wcwidth 0.1.7 py36_0
wheel 0.29.0 py36_0
XlsxWriter 1.0.2 <pip>
yaml 0.1.7 vc14_0 [vc14] conda-forge
zlib 1.2.11 vc14_0 [vc14] conda-forge

Python 3.5 environment:

E:\Development>activate python35

(python35) E:\Development>python
Python 3.5.5 | packaged by conda-forge | (default, Feb 13 2018, 06:15:35) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> exit()

(python35) E:\Development>conda list
# packages in environment at C:\Users\uqasnosw\AppData\Local\Continuum\Miniconda3\envs\python35:
#
# Name Version Build Channel
absl-py 0.2.0 <pip>
astor 0.6.2 <pip>
atari-py 0.1.1 <pip>
backcall 0.1.0 py_0 conda-forge
baselines 0.1.5 <pip>
blas 1.1 openblas conda-forge
bleach 2.1.3 py_0 conda-forge
bleach 1.5.0 <pip>
Box2D 2.3.2 <pip>
ca-certificates 2018.1.18 0 conda-forge
certifi 2018.1.18 py35_0 conda-forge
cffi 1.11.5 py35_0 conda-forge
chardet 3.0.4 <pip>
click 6.7 <pip>
cloudpickle 0.5.2 <pip>
colorama 0.3.9 py35_0 conda-forge
cvxopt 1.2.0 py35_blas_openblas_200 [blas_openblas] conda-forge
cycler 0.10.0 py35_0 conda-forge
Cython 0.28.1 <pip>
decorator 4.3.0 py_0 conda-forge
dill 0.2.7.1 <pip>
entrypoints 0.2.3 py35_1 conda-forge
freetype 2.8.1 vc14_0 [vc14] conda-forge
future 0.16.0 <pip>
gast 0.2.0 <pip>
glfw 1.6.0 <pip>
glpk 4.65 vc14_0 [vc14] conda-forge
grpcio 1.11.0 <pip>
gym 0.9.6 <pip>
html5lib 0.9999999 <pip>
html5lib 1.0.1 py_0 conda-forge
icc_rt 2017.0.4 h97af966_0
icu 58.2 vc14_0 [vc14] conda-forge
idna 2.6 <pip>
imageio 2.3.0 <pip>
intel-openmp 2018.0.0 8
ipykernel 4.8.2 py35_0 conda-forge
ipython 6.3.1 py35_0 conda-forge
ipython_genutils 0.2.0 py35_0 conda-forge
ipywidgets 7.2.1 py35_1 conda-forge
jedi 0.12.0 py35_0 conda-forge
jinja2 2.10 py35_0 conda-forge
joblib 0.11 <pip>
jpeg 9b vc14_2 [vc14] conda-forge
jsonschema 2.6.0 py35_1 conda-forge
jupyter 1.0.0 py_1 conda-forge
jupyter_client 5.2.3 py35_0 conda-forge
jupyter_console 5.2.0 py35_0 conda-forge
jupyter_core 4.4.0 py_0 conda-forge
kiwisolver 1.0.1 py35_1 conda-forge
libflang 5.0.0 vc14_20180208 [vc14] conda-forge
libpng 1.6.34 vc14_0 [vc14] conda-forge
libsodium 1.0.16 vc14_0 [vc14] conda-forge
llvm-meta 5.0.0 0 conda-forge
m2w64-dsdp 5.8 1
m2w64-fftw 3.3.4 6
m2w64-gcc-libgfortran 5.3.0 6
m2w64-gcc-libs 5.3.0 7
m2w64-gcc-libs-core 5.3.0 7
m2w64-glpk 4.61 1
m2w64-gmp 6.1.0 2
m2w64-gsl 2.1 2
m2w64-libwinpthread-git 5.0.0.4634.697f757 2
m2w64-openblas 0.2.19 1
Markdown 2.6.11 <pip>
markupsafe 1.0 py35_0 conda-forge
matplotlib 2.2.2 py35_1 conda-forge
metis 5.1.0 vc14_3 [vc14] conda-forge
mistune 0.8.3 py35_1 conda-forge
mkl 2018.0.2 1
mkl_fft 1.0.1 py35_1 conda-forge
mkl_random 1.0.1 py35_0 conda-forge
mpi4py 3.0.0 <pip>
msys2-conda-epoch 20160418 1
mujoco-py 1.50.1.53 <pip>
nbconvert 5.3.1 py_1 conda-forge
nbformat 4.4.0 py35_0 conda-forge
notebook 5.4.1 py35_0 conda-forge
numpy 1.14.2 py35_blas_openblas_200 [blas_openblas] conda-forge
openblas 0.2.20 vc14_7 [vc14] conda-forge
openmp 5.0.0 vc14_1 [vc14] conda-forge
openssl 1.0.2n vc14_0 [vc14] conda-forge
pandoc 2.1.3 0 conda-forge
pandocfilters 1.4.2 py35_0 conda-forge
parso 0.2.0 py_0 conda-forge
pickleshare 0.7.4 py35_0 conda-forge
Pillow 5.1.0 <pip>
pip 10.0.1 <pip>
pip 9.0.3 py35_0 conda-forge
progressbar2 3.37.1 <pip>
prompt_toolkit 1.0.15 py35_0 conda-forge
protobuf 3.5.2.post1 <pip>
pycparser 2.18 <pip>
pycparser 2.18 py35_0 conda-forge
pyglet 1.3.1 <pip>
pygments 2.2.0 py35_0 conda-forge
PyOpenGL 3.1.0 <pip>
pyparsing 2.2.0 py35_0 conda-forge
pyqt 5.6.0 py35_4 conda-forge
pyreadline 2.1 <pip>
python 3.5.5 0 conda-forge
python-dateutil 2.7.2 py_0 conda-forge
python-utils 2.3.0 <pip>
pytorch-cpu 0.4.0 py35_cpuhe774522_1 pytorch
pytz 2018.3 py_0 conda-forge
pywinpty 0.5 py35_2 conda-forge
pyzmq 17.0.0 <pip>
pyzmq 17.0.0 py35_4 conda-forge
qt 5.6.2 vc14_1 [vc14] conda-forge
qtconsole 4.3.1 py35_0 conda-forge
requests 2.18.4 <pip>
scikit-learn 0.19.1 py35h2037775_0
scipy 1.0.1 py35hce232c7_0
send2trash 1.5.0 py_0 conda-forge
setuptools 39.0.1 py35_0 conda-forge
simplegeneric 0.8.1 py35_0 conda-forge
sip 4.18 py35_1 conda-forge
six 1.11.0 py35_1 conda-forge
suitesparse 5.1.2 blas_openblas_vc14_202 [blas_openblas vc14] conda-forge
tbb 2018_20171205 vc14_0 [vc14] conda-forge
tensorboard 1.7.0 <pip>
tensorflow 1.7.0 <pip>
termcolor 1.1.0 <pip>
terminado 0.8.1 py35_0 conda-forge
testpath 0.3.1 py35_0 conda-forge
torchvision 0.2.1 <pip>
tornado 5.0.2 py35_0 conda-forge
tqdm 4.23.0 <pip>
traitlets 4.3.2 py35_0 conda-forge
urllib3 1.22 <pip>
vc 14 0 conda-forge
vs2015_runtime 14.0.25420 0 conda-forge
wcwidth 0.1.7 py35_0 conda-forge
webencodings 0.5.1 py35_0 conda-forge
Werkzeug 0.14.1 <pip>
wheel 0.31.0 py35_0 conda-forge
widgetsnbextension 3.2.1 py35_0 conda-forge
win_unicode_console 0.5 py35_0 conda-forge
wincertstore 0.2 py35_0 conda-forge
winpty 0.4.3 vc14_2 [vc14] conda-forge
xlsxwriter 1.0.2 py_0 conda-forge
zeromq 4.2.5 vc14_1 [vc14] conda-forge
zlib 1.2.11 vc14_0 [vc14] conda-forge
zmq 0.0.0 <pip>

Python 2.7 environment (can't reproduce here):

E:\Development>activate python27

(python27) E:\Development>python
Python 2.7.13 |Anaconda 4.4.0 (64-bit)| (default, May 11 2017, 13:17:26) [MSC v.1500 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
Anaconda is brought to you by Continuum Analytics.
Please check out: http://continuum.io/thanks and https://anaconda.org
>>> exit()

(python27) E:\Development>conda list
# packages in environment at C:\Users\uqasnosw\AppData\Local\Continuum\Miniconda3\envs\python27:
#
# Name Version Build Channel
_license 1.1 py27_1
alabaster 0.7.10 py27_0
anaconda 4.4.0 np112py27_0
anaconda-client 1.6.3 py27_0
anaconda-navigator 1.6.2 py27_0
anaconda-project 0.6.0 py27_0
asn1crypto 0.22.0 py27_0
astroid 1.4.9 py27_0
astropy 1.3.2 np112py27_0
babel 2.4.0 py27_0
backports 1.0 py27_0
backports_abc 0.5 py27_0
beautifulsoup4 4.6.0 py27_0
bitarray 0.8.1 py27_1
blaze 0.10.1 py27_0
bleach 1.5.0 py27_0
bokeh 0.12.5 py27_1
boto 2.46.1 py27_0
bottleneck 1.2.1 np112py27_0
bzip2 1.0.6 vc9_3 [vc9]
cdecimal 2.3 py27_2
cffi 1.10.0 py27_0
chardet 3.0.3 py27_0
click 6.7 py27_0
cloudpickle 0.2.2 py27_0
clyent 1.2.2 py27_0
colorama 0.3.9 py27_0
comtypes 1.1.2 py27_0
configparser 3.5.0 py27_0
console_shortcut 0.1.1 py27_1
contextlib2 0.5.5 py27_0
cryptography 1.8.1 py27_0
curl 7.52.1 vc9_0 [vc9]
cvxopt 1.1.9 <pip>
cycler 0.10.0 py27_0
cython 0.25.2 py27_0
cytoolz 0.8.2 py27_0
dask 0.14.3 py27_1
datashape 0.5.4 py27_0
decorator 4.0.11 py27_0
distributed 1.16.3 py27_0
docutils 0.13.1 py27_0
entrypoints 0.2.2 py27_1
enum34 1.1.6 py27_0
et_xmlfile 1.0.1 py27_0
fastcache 1.0.2 py27_1
flask 0.12.2 py27_0
flask-cors 3.0.2 py27_0
freetype 2.5.5 vc9_2 [vc9]
funcsigs 1.0.2 py27_0
functools32 3.2.3.2 py27_0
futures 3.1.1 py27_0
get_terminal_size 1.0.0 py27_0
gevent 1.2.1 py27_0
greenlet 0.4.12 py27_0
grin 1.2.1 py27_3
h5py 2.7.0 np112py27_0
hdf5 1.8.15.1 vc9_4 [vc9]
heapdict 1.0.0 py27_1
html5lib 0.999 py27_0
icu 57.1 vc9_0 [vc9]
idna 2.5 py27_0
imagesize 0.7.1 py27_0
ipaddress 1.0.18 py27_0
ipykernel 4.6.1 py27_0
ipython 5.3.0 py27_0
ipython_genutils 0.2.0 py27_0
ipywidgets 6.0.0 py27_0
isort 4.2.5 py27_0
itsdangerous 0.24 py27_0
jdcal 1.3 py27_0
jedi 0.10.2 py27_2
jinja2 2.9.6 py27_0
jpeg 9b vc9_0 [vc9]
jsonschema 2.6.0 py27_0
jupyter 1.0.0 py27_3
jupyter_client 5.0.1 py27_0
jupyter_console 5.1.0 py27_0
jupyter_core 4.3.0 py27_0
lazy-object-proxy 1.2.2 py27_0
libpng 1.6.27 vc9_0 [vc9]
libtiff 4.0.6 vc9_3 [vc9]
llvmlite 0.18.0 py27_0
locket 0.2.0 py27_1
lxml 3.7.3 py27_0
markupsafe 0.23 py27_2
matplotlib 2.0.2 np112py27_0
menuinst 1.4.7 py27_0
mistune 0.7.4 py27_0
mkl 2017.0.1 0
mkl-service 1.1.2 py27_3
mpmath 0.19 py27_1
msgpack-python 0.4.8 py27_0
multipledispatch 0.4.9 py27_0
navigator-updater 0.1.0 py27_0
nbconvert 5.1.1 py27_0
nbformat 4.3.0 py27_0
networkx 1.11 py27_0
nltk 3.2.3 py27_0
nose 1.3.7 py27_1
notebook 5.0.0 py27_0
numba 0.33.0 np112py27_0
numexpr 2.6.2 np112py27_0
numpy 1.12.1 py27_0
numpydoc 0.6.0 py27_0
odo 0.5.0 py27_1
olefile 0.44 py27_0
openpyxl 2.4.7 py27_0
openssl 1.0.2l vc9_0 [vc9]
packaging 16.8 py27_0
pandas 0.20.1 np112py27_0
pandocfilters 1.4.1 py27_0
partd 0.3.8 py27_0
path.py 10.3.1 py27_0
pathlib2 2.2.1 py27_0
patsy 0.4.1 py27_0
pep8 1.7.0 py27_0
pickleshare 0.7.4 py27_0
pillow 4.1.1 py27_0
pip 9.0.1 py27_1
ply 3.10 py27_0
prompt_toolkit 1.0.14 py27_0
psutil 5.2.2 py27_0
py 1.4.33 py27_0
pycosat 0.6.2 py27_0
pycparser 2.17 py27_0
pycrypto 2.6.1 py27_6
pycurl 7.43.0 py27_2
pyflakes 1.5.0 py27_0
pygments 2.2.0 py27_0
pylint 1.6.4 py27_1
pyodbc 4.0.16 py27_0
pyopenssl 17.0.0 py27_0
pyparsing 2.1.4 py27_0
pyqt 5.6.0 py27_2
pytables 3.2.2 np112py27_4
pytest 3.0.7 py27_0
python 2.7.13 1
python-dateutil 2.6.0 py27_0
pytz 2017.2 py27_0
pywavelets 0.5.2 np112py27_0
pywin32 220 py27_2
pyyaml 3.12 py27_0
pyzmq 16.0.2 py27_0
qt 5.6.2 vc9_4 [vc9]
qtawesome 0.4.4 py27_0
qtconsole 4.3.0 py27_0
qtpy 1.2.1 py27_0
requests 2.14.2 py27_0
rope 0.9.4 py27_1
ruamel_yaml 0.11.14 py27_1
scandir 1.5 py27_0
scikit-image 0.13.0 np112py27_0
scikit-learn 0.18.1 np112py27_1
scipy 0.19.0 np112py27_0
seaborn 0.7.1 py27_0
setuptools 27.2.0 py27_1
simplegeneric 0.8.1 py27_1
singledispatch 3.4.0.3 py27_0
sip 4.18 py27_0
six 1.10.0 py27_0
snowballstemmer 1.2.1 py27_0
sortedcollections 0.5.3 py27_0
sortedcontainers 1.5.7 py27_0
sphinx 1.5.6 py27_0
spyder 3.1.4 py27_0
sqlalchemy 1.1.9 py27_0
ssl_match_hostname 3.4.0.2 py27_1
statsmodels 0.8.0 np112py27_0
subprocess32 3.2.7 py27_0
sympy 1.0 py27_0
tblib 1.3.2 py27_0
testpath 0.3 py27_0
tk 8.5.18 vc9_0 [vc9]
toolz 0.8.2 py27_0
tornado 4.5.1 py27_0
traitlets 4.3.2 py27_0
unicodecsv 0.14.1 py27_0
vs2008_runtime 9.00.30729.5054 0
vs2015_runtime 14.0.25123 0
wcwidth 0.1.7 py27_0
werkzeug 0.12.2 py27_0
wheel 0.29.0 py27_0
widgetsnbextension 2.0.0 py27_0
win_unicode_console 0.5 py27_0
wrapt 1.10.10 py27_0
xlrd 1.0.0 py27_0
xlsxwriter 0.9.6 py27_0
xlwings 0.10.4 py27_0
xlwt 1.2.0 py27_0
zict 0.1.2 py27_0
zlib 1.2.8 vc9_3 [vc9]

My system configuration (from DxDiag) is here.

NB: This seems to be a re-incarnation of #4813.

Thank you in advance for any help resolving this.

Issue 2:
Hi,

I've noticed that numpy's testsuite hangs when numpy is built against MKL 2018.2 - but runs to completion when built against MKL 2017.1.

This is the case for numpy v1.14.2, 1.14.x HEAD and master branches.

I'm on CentOS 7.4 x86_64 on a Broadwell processor, python 2.7.5 (but also affects other pythons), Cython 0.28.2, nose 1.3.7.

By executing this: python -c "import numpy; numpy.test(verbose=2)"

I can see that the hang occurs while running this test: numpy.distutils.tests.test_exec_command.TestExecCommand.test_basic

At this point, the python interpreter is consuming an entire CPU core and, if I strace it, I see a stream of identical lines, all showing:

sched_yield() = 0

Any ideas, please?

Thanks!