I am currently (occasionally) running into the same problem, using Python 3.6.0 on OSX 10.12.3.

I cannot reproduce this segmentation fault reliably, it happens after running for a while in production. This appears to be similar to issue 13829.

python traceback (trimmed):

Fatal Python error: Segmentation fault

Current thread 0x00007000065fb000 (most recent call first):
  File "/usr/local/Cellar/python3/3.6.0_1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 2592 in proxy_bypass_macosx_sysconf
  File "/usr/local/Cellar/python3/3.6.0_1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 2616 in proxy_bypass
  File "/Users/daniel/Workspace/venv/lib/python3.6/site-packages/requests/utils.py", line 677 in should_bypass_proxies
  File "/Users/daniel/Workspace/venv/lib/python3.6/site-packages/requests/utils.py", line 693 in get_environ_proxies
  File "/Users/daniel/Workspace/venv/lib/python3.6/site-packages/requests/sessions.py", line 686 in merge_environment_settings
  File "/Users/daniel/Workspace/venv/lib/python3.6/site-packages/requests/sessions.py", line 509 in request
  File "/Users/daniel/Workspace/venv/lib/python3.6/site-packages/requests/api.py", line 58 in request


crash dump traceback (trimmed):

* thread #1: tid = 0x0000, 0x00007fffc1ef0dd6 libsystem_kernel.dylib`__pthread_kill + 10, stop reason = signal SIGSTOP
  * frame #0: 0x00007fffc1ef0dd6 libsystem_kernel.dylib`__pthread_kill + 10
    frame #1: 0x00007fffc1fdc787 libsystem_pthread.dylib`pthread_kill + 90
    frame #2: 0x00007fffc1e07497 libsystem_c.dylib`raise + 26
    frame #3: 0x00007fffc1fcfbba libsystem_platform.dylib`_sigtramp + 26
    frame #4: 0x00007fffc1da188f libdispatch.dylib`_dispatch_queue_push + 172
    frame #5: 0x00007fffc1d91572 libdispatch.dylib`_dispatch_mach_msg_send + 657
    frame #6: 0x00007fffc1d924ba libdispatch.dylib`_dispatch_mach_send_drain + 280
    frame #7: 0x00007fffc1da91ea libdispatch.dylib`_dispatch_mach_send_push_and_trydrain + 487
    frame #8: 0x00007fffc1da6745 libdispatch.dylib`_dispatch_mach_send_msg + 282
    frame #9: 0x00007fffc1da6804 libdispatch.dylib`dispatch_mach_send_with_result + 50
    frame #10: 0x00007fffc201f25e libxpc.dylib`_xpc_connection_enqueue + 104
    frame #11: 0x00007fffc201eca3 libxpc.dylib`xpc_connection_send_message_with_reply + 152
    frame #12: 0x00007fffac99b8e5 CoreFoundation`__80-[CFPrefsSearchListSource alreadylocked_generationCountFromListOfSources:count:]_block_invoke_2 + 133
    frame #13: 0x00007fffac9cb4e4 CoreFoundation`-[_CFXPreferences withConnectionForRole:performBlock:] + 36
    frame #14: 0x00007fffac99b817 CoreFoundation`__80-[CFPrefsSearchListSource alreadylocked_generationCountFromListOfSources:count:]_block_invoke + 199
    frame #15: 0x00007fffac99b662 CoreFoundation`-[CFPrefsSearchListSource alreadylocked_generationCountFromListOfSources:count:] + 226
    frame #16: 0x00007fffac81ee80 CoreFoundation`-[CFPrefsSearchListSource alreadylocked_copyDictionary] + 336
    frame #17: 0x00007fffac81eb5c CoreFoundation`-[CFPrefsSearchListSource alreadylocked_copyValueForKey:] + 60
    frame #18: 0x00007fffac94dd75 CoreFoundation`-[CFPrefsSource copyValueForKey:] + 53
    frame #19: 0x00007fffac9c9b00 CoreFoundation`__76-[_CFXPreferences copyAppValueForKey:identifier:container:configurationURL:]_block_invoke + 32
    frame #20: 0x00007fffac99ca32 CoreFoundation`__108-[_CFXPreferences(SearchListAdditions) withSearchListForIdentifier:container:cloudConfigurationURL:perform:]_block_invoke + 290
    frame #21: 0x00007fffac99c8a9 CoreFoundation`-[_CFXPreferences(SearchListAdditions) withSearchListForIdentifier:container:cloudConfigurationURL:perform:] + 345
    frame #22: 0x00007fffac9c9a66 CoreFoundation`-[_CFXPreferences copyAppValueForKey:identifier:container:configurationURL:] + 310
    frame #23: 0x00007fffb343a56f SystemConfiguration`SCDynamicStoreCopyProxiesWithOptions + 164
    frame #24: 0x000000010b36f926 _scproxy.cpython-36m-darwin.so`get_proxy_settings + 24
    frame #25: 0x000000010942148b Python`_PyCFunction_FastCallDict + 529
    frame #26: 0x0000000109488959 Python`call_function + 562
    frame #27: 0x0000000109485d10 Python`_PyEval_EvalFrameDefault + 26835