test_tracemalloc: test_tracemalloc_track_race() crashs on GHA iOS CI

Crash report

iOS: https://github.com/python/cpython/actions/runs/26457870719/job/77897032289?pr=150441

This issue is likely the same as issue gh-143143, but I'm not 100% sure so I created a separated issue.

    0:11:19 load avg: 2.79 [435/505] test_tracemalloc
  Fatal Python error: Segmentation fault
  
  Current thread 0x0000000322193000 (most recent call first):
  
  Thread 0x0000000321187000 (most recent call first):
  
  Thread 0x000000032017b000 (most recent call first):
  
  (...)
  
  Thread 0x00000003100bb000 (most recent call first):
  
  <freed thread state>
  
  Current thread's C stack trace (most recent call first):
    Binary file "/Users/runner/work/cpython/cpython/cross-build/iOS-testbed.1779809388208/DerivedData/Build/Products/Debug-iphonesimulator/Python.framework/Python", at _Py_DumpStack+0x44 [0x102407804]
    Binary file "/Users/runner/work/cpython/cpython/cross-build/iOS-testbed.1779809388208/DerivedData/Build/Products/Debug-iphonesimulator/Python.framework/Python", at faulthandler_fatal_error+0x264 [0x10241e4a0]
    Binary file "/usr/lib/system/libsystem_platform.dylib", at _sigtramp+0x34 [0x100a6f7e0]
    Binary file "/Users/runner/work/cpython/cpython/cross-build/iOS-testbed.1779809388208/DerivedData/Build/Products/Debug-iphonesimulator/Python.framework/Python", at PyGILState_Ensure+0xf8 [0x1023eab50]
    Binary file "/Users/runner/work/cpython/cpython/cross-build/iOS-testbed.1779809388208/DerivedData/Build/Products/Debug-iphonesimulator/Python.framework/Python", at PyGILState_Ensure+0xf8 [0x1023eab50]
    Binary file "/Users/runner/work/cpython/cpython/cross-build/iOS-testbed.1779809388208/DerivedData/Build/Products/Debug-iphonesimulator/Python.framework/Python", at tracemalloc_alloc+0xa8 [0x1024097a4]
    Binary file "/Users/runner/work/cpython/cpython/cross-build/iOS-testbed.1779809388208/DerivedData/Build/Products/Debug-iphonesimulator/Python.framework/Python", at PyGILState_Ensure+0x58 [0x1023eaab0]
    Binary file "/Users/runner/work/cpython/cpython/cross-build/iOS-testbed.1779809388208/DerivedData/Build/Products/Debug-iphonesimulator/Python.framework/Python", at PyTraceMalloc_Track+0x34 [0x1024088ec]
    Binary file "/Users/runner/Library/Developer/CoreSimulator/Devices/D3F1CE55-196D-4DC8-9D1F-6D2D3AB3D118/data/Containers/Bundle/Application/130788EC-7B24-4534-8FF0-89C57EC65B80/iOSTestbed.app/Frameworks/_testcapi.framework/_testcapi", at tracemalloc_track_race_thread+0x20 [0x106f251b0]
    (...)
  
  Extension modules: _testcapi, _testinternalcapi, _testlimitedcapi, _testmultiphase, _testbuffer, _ctypes_test, xxsubtype, _testsinglephase_basic_wrapper, _testsinglephase_basic_copy, _testsinglephase_with_reinit, _testsinglephase_with_state, _test_non_isolated, _test_shared_gil_only, _test_no_multiple_interpreter_slot, _testsinglephase (total: 15)
  
  Restarting after unexpected exit, crash, or test timeout in -[TestbedTests testPython]; summary will include totals from previous launches.

Commencez par test_tracemalloc_track_race() et reproduisez le crash du job iOS GitHub Actions lié. Comparez l’échec avec l’issue gh-143143 et examinez les frames de pile signalées PyGILState_Ensure, tracemalloc_alloc et PyTraceMalloc_Track. C’est terminé lorsque la race condition ne provoque plus de crash du testbed iOS et que test_tracemalloc passe.