Segmentation fault when running Flask development server in Alpine Linux

[rossgray]

Hi,

I am getting a segmentation fault when using Raven with the Flask development server on Alpine Linux. Oddly, this issue only appears to occur when I install a recent version of the requests library (>= v2.13.0) (even if I don't import that library in my code). This issue is only specific to Alpine - it works fine on other Python Docker images. The issue occurs on versions of Raven >= 5.4.0.

I think the segmentation fault is related to some imports within the Raven library.
When I change the following lines it fixes the problem:
https://github.com/getsentry/raven-python/blob/master/raven/conf/remote.py#L18-L19

from:

from raven.transport.threaded import ThreadedHTTPTransport
from raven.transport.http import HTTPTransport

to:

from raven.transport import ThreadedHTTPTransport
from raven.transport import HTTPTransport

i.e. remove the submodule, which isn't needed since in transport/__init__.py there is:

from raven.transport.http import *  # NOQA

I have created a test project to reproduce this issue:
https://github.com/ingresso-group/flask-raven-debug

Environment:

• python:3.6-alpine Docker image
• Python 3.6.1
• Flask 0.12
• Werkzeug 0.12.1
• Raven 6.0.0

[beaugunderson]

There are two additional open issues that involve python:3.6-alpine and threading:

• SEGFAULT when certain modules are used in a project with Alpine 3.6/Python 3.6 docker-library/python#211
• ujson segfault on alpine linux ultrajson/ultrajson#254

I think the root cause for this issue and the other two is the same (and I'm offering a $100 bounty for docker-library/python#211)

[beaugunderson]

@rossgray based on my research from those other issues I'm confident that this is an issue with musl's smaller default stack size; you can try this workaround or try upgrading to requests>=2.18.1, which does not suffer from the segfault in my experience (but you may still experience it if you use other dependencies, especially ones that include ultrajson).

[beaugunderson]

here's a link to some background discussion on increasing the stack size in musl, for reference.

[rossgray]

Thank you @beaugunderson ! I can confirm that upgrading to requests 2.18.1 resolves the issue (at least for now)