Fatal Python error: Segmentation fault

Current thread 0x00007ffff7fe5700:
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/matplotlib-1.5.x-py3.3-linux-x86_64.egg/matplotlib/tri/triangulation.py", line 193 in neighbors
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/matplotlib-1.5.x-py3.3-linux-x86_64.egg/matplotlib/tri/tritools.py", line 190 in get_flat_tri_mask
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/matplotlib-1.5.x-py3.3-linux-x86_64.egg/matplotlib/tests/test_triangulation.py", line 876 in test_tritools
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/nose/case.py", line 198 in runTest
  File "/opt/python/3.3.5/lib/python3.3/unittest/case.py", line 384 in _executeTestPart
  File "/opt/python/3.3.5/lib/python3.3/unittest/case.py", line 439 in run
  File "/opt/python/3.3.5/lib/python3.3/unittest/case.py", line 491 in __call__
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/nose/case.py", line 152 in runTest
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/nose/case.py", line 134 in run
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/nose/case.py", line 46 in __call__
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/nose/plugins/multiprocess.py", line 812 in run
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/nose/suite.py", line 178 in __call__
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/nose/plugins/multiprocess.py", line 812 in run
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/nose/suite.py", line 178 in __call__
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/nose/plugins/multiprocess.py", line 715 in __runner
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/nose/plugins/multiprocess.py", line 652 in runner
  File "/opt/python/3.3.5/lib/python3.3/multiprocessing/process.py", line 95 in run
  File "/opt/python/3.3.5/lib/python3.3/multiprocessing/process.py", line 258 in _bootstrap
  File "/opt/python/3.3.5/lib/python3.3/multiprocessing/forking.py", line 103 in __init__
  File "/opt/python/3.3.5/lib/python3.3/multiprocessing/process.py", line 111 in start
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/nose/plugins/multiprocess.py", line 343 in startProcess
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/nose/plugins/multiprocess.py", line 380 in run
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/nose/core.py", line 207 in runTests
  File "/opt/python/3.3.5/lib/python3.3/unittest/main.py", line 125 in __init__
  File "/home/travis/virtualenv/python3.3.5/lib/python3.3/site-packages/nose/core.py", line 121 in __init__
  File "../matplotlib/tests.py", line 47 in run
  File "../matplotlib/tests.py", line 57 in <module>