After upgrading from Debian Stretch to Bullseye (e.g. Python 3.5 → 3.9) we've got the following uWSGI segfault:
uWSGI process 314459 got Segmentation Fault !!!
*** backtrace of 314459 ***
/usr/bin/uwsgi(uwsgi_backtrace+0x2f) [0x558ed0a9b96f]
/usr/bin/uwsgi(uwsgi_segfault+0x23) [0x558ed0a9bd73]
/lib/x86_64-linux-gnu/libc.so.6(+0x3bd60) [0x7fd71a9e0d60]
/usr/lib/x86_64-linux-gnu/libpython3.9.so.1.0(PyErr_Occurred+0xe) [0x7fd7184d247e]
/usr/lib/x86_64-linux-gnu/libpython3.9.so.1.0(+0x12d655) [0x7fd718586655]
/usr/lib/x86_64-linux-gnu/libpython3.9.so.1.0(_PyType_Lookup+0x2d) [0x7fd71858678d]
/usr/lib/x86_64-linux-gnu/libpython3.9.so.1.0(_PyObject_GenericGetAttrWithDict+0x4d) [0x7fd71856a73d]
/usr/lib/x86_64-linux-gnu/libpython3.9.so.1.0(+0x1121c9) [0x7fd71856b1c9]
/usr/lib/x86_64-linux-gnu/libpython3.9.so.1.0(PyObject_GetAttrString+0x3b) [0x7fd71856730b]
/usr/lib/x86_64-linux-gnu/libpython3.9.so.1.0(PyObject_HasAttrString+0x7) [0x7fd718567d87]
/usr/lib/uwsgi/plugins/python3_plugin.so(uwsgi_python_autoreloader_thread+0x179) [0x7fd718a04d19]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x8ea7) [0x7fd71b2d3ea7]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x3f) [0x7fd71aaa2def]
*** end of backtrace ***
How can we find out what is causing this and how to fix the issue?
Disabling psycopg2 SSL mode does not help.
This line in the backtrace made me think that maybe the issue has something to do with automatic reloading:
/usr/lib/uwsgi/plugins/python3_plugin.so(uwsgi_python_autoreloader_thread+0x179) [0x7fd718a04d19]
Then I found this issue: https://github.com/unbit/uwsgi/issues/1968
As a workaround I disabled autoreload and the service recovered. According to this page autoreloading is only for development purposes.