diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-02-11-20-38-37.gh-issue-129983._1Fujo.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-02-11-20-38-37.gh-issue-129983._1Fujo.rst new file mode 100644 index 00000000000000..9b435703eb734a --- /dev/null +++ b/Misc/NEWS.d/next/Core_and_Builtins/2025-02-11-20-38-37.gh-issue-129983._1Fujo.rst @@ -0,0 +1 @@ +Fix data race in compile_template in :file:`sre.c`. diff --git a/Modules/_sre/sre.c b/Modules/_sre/sre.c index 0d8d4843d33c1b..54f0e64d4819f1 100644 --- a/Modules/_sre/sre.c +++ b/Modules/_sre/sre.c @@ -1167,13 +1167,21 @@ compile_template(_sremodulestate *module_state, PatternObject *pattern, PyObject *template) { /* delegate to Python code */ - PyObject *func = module_state->compile_template; + PyObject *func = FT_ATOMIC_LOAD_PTR(module_state->compile_template); if (func == NULL) { func = PyImport_ImportModuleAttrString("re", "_compile_template"); if (func == NULL) { return NULL; } +#ifdef Py_GIL_DISABLED + PyObject *other_func = NULL; + if (!_Py_atomic_compare_exchange_ptr(&module_state->compile_template, &other_func, func)) { + Py_DECREF(func); + func = other_func; + } +#else Py_XSETREF(module_state->compile_template, func); +#endif } PyObject *args[] = {(PyObject *)pattern, template};