Fatal Python error: Segmentation fault

Describe the bug

My code I use to run everyday started showing error after the recent update ,
It starts by showing me some warning: net time use this else it won't work in the next update and I fix as it says and update aiohttp with python, the I start encounters this bug

Current thread's C stack trace (most recent call first):

Extension modules: _cffi_backend, aiohttp._http_writer, aiohttp._http_parser, aiohttp._websocket.mask, aiohttp._websocket.reader_c (total: 5)
Segmentation faultt

To Reproduce

Just look at the infos above

Expected behavior

Decoding responds fails on some site and instead of it to raise Expectation it crush
Am already using try and except Exception

Most crush here
Body = await response.text(errors="ignore")

Logs/tracebacks

Fatal Python error: Segmentation fault
                                                                Thread 0x00000073033f8cb0 (most recent call first):
  File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/pycares/__init__.py", line 430 in _run_safe_shutdown_loop
  File "/data/data/com.termux/files/usr/lib/python3.14/threading.py", line 1024 in run
  File "/data/data/com.termux/files/usr/lib/python3.14/threading.py", line 1082 in _bootstrap_inner
  File "/data/data/com.termux/files/usr/lib/python3.14/threading.py", line 1044 in _bootstrap
                                                                Current thread 0x0000007395ae4098 (most recent call first):
  File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/client_proto.py", line 326 in data_received
  File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/base_protocol.py", line 89 in resume_reading
  File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/client_proto.py", line 194 in resume_reading
  File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/streams.py", line 556 in _read_nowait_chunk
  File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/streams.py", line 568 in _read_nowait
  File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/streams.py", line 462 in readany
  File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/streams.py", line 437 in read
  File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/client_reqrep.py", line 715 in read
  File "/storage/emulated/0/test/test-eye/s/mycode.py", line 722 in worker4
  File "/storage/emulated/0/test/test-eye/s/mycode.py", line 614 in worker2
  File "/data/data/com.termux/files/usr/lib/python3.14/asyncio/events.py", line 94 in _run
  File "/data/data/com.termux/files/usr/lib/python3.14/asyncio/base_events.py", line 2056 in _run_once                            File "/data/data/com.termux/files/usr/lib/python3.14/asyncio/base_events.py", line 677 in run_forever
  File "/data/data/com.termux/files/usr/lib/python3.14/asyncio/base_events.py", line 706 in run_until_complete
  File "/data/data/com.termux/files/usr/lib/python3.14/asyncio/runners.py", line 128 in run
  File "/data/data/com.termux/files/usr/lib/python3.14/asyncio/runners.py", line 205 in run
  File "/storage/emulated/0/test/test-eye/s/mycode.py", line 1367 in <module>

Current thread's C stack trace (most recent call first):
  <cannot get C stack on this system>

Extension modules: _cffi_backend, aiohttp._http_writer, aiohttp._http_parser, aiohttp._websocket.mask, aiohttp._websocket.reader_c (total: 5)
Segmentation fault

Python Version

Python 3.14.6

aiohttp Version

$ python -m pip show aiohttp
Name: aiohttp
Version: 3.14.2

multidict Version

Name: multidict
Version: 6.7.1                                                  Summary: multidict implementation

propcache Version

Name: propcache
Version: 0.5.2

yarl Version

Name: yarl
Version: 1.24.5

OS

Termux

Related component

Server

Additional context

No response

Code of Conduct

I agree to follow the aio-libs Code of Conduct

Can you test without aiodns installed? And if that works, then verify that you were using the latest version of both aiodns and pycares.

Can you test without aiodns installed? And if that works, then verify that you were using the latest version of both aiodns and pycares.

I think it's from aiohttp, i remove aiodns and it usage from my code still crush

I think the best solution is to switch to httpx

I think it's from aiohttp, i remove aiodns and it usage from my code still crush

Your traceback shows pycares, which is used by aiodns. Please follow the instructions and confirm the results. We can't help you if you don't give us any information...

If it's still failing without aiodns, then please paste the full traceback again.

Also verifying if it works without extensions (run with AIOHTTP_NO_EXTENSIONS=1) would help. That will tell us if it's a parser issue (we upgraded llhttp), and that's the only C code we run.

I'm unclear how your code works though, it appears to be using threading, which generally doesn't make sense in an asyncio application.. Any code to look at or reproduce the issue would obviously be very helpful.

File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/client_proto.py", line 326 in data_received

This line is feeding data to the parser, so it probably is related to the C parser (llhttp). But, we need more information on how to reproduce. Can you provide code that shows the problem?

File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/client_proto.py", line 326 in data_received

This line is feeding data to the parser, so it probably is related to the C parser (llhttp). But, we need more information on how to reproduce. Can you provide code that shows the problem?

Please I remove aiodns, uvloop completely from my code and still crash

Fatal Python error: Segmentation fault
Current thread 0x000000756c59f098 (most recent call first): File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/client_proto.py", line 326 in data_received File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/base_protocol.py", line 89 in resume_reading
File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/client_proto.py", line 194 in resume_reading
File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/streams.py", line 556 in _read_nowait_chunk File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/streams.py", line 569 in _read_nowait
File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/streams.py", line 462 in readany File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/streams.py", line 437 in read
File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/client_reqrep.py", line 715 in read
File "/data/data/com.termux/files/usr/lib/python3.14/site-packages/aiohttp/client_reqrep.py", line 757 in text
File "/storage/emulated/0/test/test-eye/s/news.py", line 730 in sprayworker
File "/storage/emulated/0/test/test-eye/s/news.py", line 622 in worker2
File "/data/data/com.termux/files/usr/lib/python3.14/asyncio/events.py", line 94 in _run
File "/data/data/com.termux/files/usr/lib/python3.14/asyncio/base_events.py", line 2056 in _run_once
File "/data/data/com.termux/files/usr/lib/python3.14/asyncio/base_events.py", line 677 in run_forever File "/data/data/com.termux/files/usr/lib/python3.14/asyncio/base_events.py", line 706 in run_until_complete
File "/data/data/com.termux/files/usr/lib/python3.14/asyncio/runners.py", line 128 in run
File "/data/data/com.termux/files/usr/lib/python3.14/asyncio/runners.py", line 205 in run
File "/storage/emulated/0/test/test-eye/s/news.py", line 1374 in
Current thread's C stack trace (most recent call first):

Extension modules: _cffi_backend, aiohttp._http_writer, aiohttp._http_parser, aiohttp._websocket.mask, aiohttp._websocket.reader_c (total: 5)
Segmentation fault

The error in my code and what is found over there
1.File "/storage/emulated/0/test/test-eye/s/news.py", line 730 in sprayworker
line 730
body = await r.text(errors='ignore')

File "/storage/emulated/0/test/test-eye/s/news.py", line 622 in worker2

line 622
ex_tabl = await sprayworker(data, "table")

It's a scraper tools, scraping from many urls and it crash after few seconds after starting (sometimes it runs about 4-6sec then crash sometimes 30-40sec) it should raise expectation but it crashes, before update I use to run the same site successfully without any crash even at high Semaphore

my complete imports
Key: all # lines are commented real in my code

import faulthandler
faulthandler.enable()
import os
import re
import ssl
import ast
import json
import time
#import uvloop
import random
#import certifi
import asyncio
import aiohttp
import hashlib
from colorama import Fore, Style, init
from fake_useragent import UserAgent
#from aiohttp.resolver import AsyncResolver
from urllib.parse import urlparse, parse_qs, urlencode, urlunparse
#the below is advice use by AI to stop the crash
os.environ['AIOHTTP_NO_EXTENSIONS'] = '1'
os.environ['UVLOOP_NO_EXTENSIONS'] = '1'

And still crash

Again, test with AIOHTTP_NO_EXTENSIONS (set this as the environment variable for the program, not inside the code).

And give us some code or anything (e.g. the payload that causes the failure; log each request you make so you know which request actually triggers the failure) that we can use to figure out what the problem is.

Yes AIOHTTP_NO_EXTENSIONS=1 python your_script.py works without crashing

it still segfaults on 3.14.3

ERROR: No matching distribution found for aiohttp==3.14.3

Or aiohttp version 3.14.3 has not been release yet

i couldn't find it either in pypi, but there are whl files here on github or you can install it from source

From github here they haven't update it yet, may be it will be update later

@taulantarapi

Thanks @taulantarapi for the email report, that's been really helpful.

We're still investigating the precise details, but right now it looks like a bug in brotlicffi, so I'd suggest you both uninstall that library for the moment.

python-hyper/brotlicffi#225

Brotlicffi might be the cause of the crash because requests fail to decode the response too but raised Exception not crash so my suggestion is, add that error to aiohttp to raise Exception when such decoding fails

Because I just checked brotlicffi repo from GitHub here and it hasn't been update recently so it's possible from aiohttp, aiohttp old version was not crashing, my suggestion is if brotlicffi fails raise Exception not crash, please take a look at it

The issue appeared in 1.2. When 1.2 was released we made a security fix which was a bit of a hack, but happened to also avoid the newly broken code path in brotlicffi. aiohttp 3.14 contained our complete fix that re-enabled that code path.

So problem exists with aiohttp 3.14+ and brotlicffi 1.2. We also require 1.2+ for our security fix, so the only option currently is to uninstall brotlicffi. I'll check if the segfault can be resolved, but you still want to uninstall it, because those exceptions are still stopping you from reading legitimate responses.

Note that this problem doesn't exist in brotli. I assume you're on a less common platform, where Google's brotli is not supported.

Yes after uninstalling brotlicffi it works👍 without crashing

Segfault: cython/cython#7857

v1.2.0.2 is out now, you can reinstall brotlicffi

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Fatal Python error: Segmentation fault #13203

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Expected behavior

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Python Version

aiohttp Version

multidict Version

propcache Version

yarl Version

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Fatal Python error: Segmentation fault #13203

Description

Describe the bug

To Reproduce

Expected behavior

Logs/tracebacks

Python Version

aiohttp Version

multidict Version

propcache Version

yarl Version

OS

Related component

Additional context

Code of Conduct

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