`test_call.test_super_deep` started segfaulting with 3.14.0a4 freethreading
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Description
Crash report
What happened?
test_super_deep (test.test_call.TestRecursion.test_super_deep) ... Fatal Python error: Segmentation fault
The test passes with a3 but segfaults with a4 — so I'm guessing stack frames grew or something. Not sure if this is the kind of regression in code that needs to be fixed, or merely recursion limit needs to be lowered.
This is Gentoo Linux amd64, CPython built with LTO + PGO, CFLAGS are -march=znver2 --param=l1-cache-size=32 --param=l1-cache-line-size=64 -O2 -pipe -frecord-gcc-switches.
Full log: dev-lang:python-3.14.0_alpha4-r100:20250117-163521.txt
CPython versions tested on:
3.14
Operating systems tested on:
Linux
Output from running 'python -VV' on the command line:
Python 3.14.0a4 experimental free-threading build (main, Jan 17 2025, 17:46:22) [GCC 14.2.1 20241221]
Linked PRs
- gh-128958
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with test.test_call.TestRecursion.test_super_deep and reproduce the segmentation fault on a 3.14.0a4 free-threading build, then compare it with 3.14.0a3. Review linked PR gh-128958 for the current investigation; done means the test no longer segfaults without masking the underlying regression.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- backend
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 20/100