`test_call.test_super_deep` started segfaulting with 3.14.0a4 freethreading

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

test.test_call.TestRecursion.test_super_deep から始め、3.14.0a4 の free-threading ビルドで segmentation fault を再現してから、3.14.0a3 と比較してください。現在の調査については、リンクされている PR gh-128958 を確認してください。完了の条件は、基礎にあるリグレッションを隠すことなく、テストで segmentation fault が発生しなくなることです。