python · vstinner · Jan 12, 2022 · Jan 12, 2022 · Jan 13, 2022
diff --git a/Include/internal/pycore_interp.h b/Include/internal/pycore_interp.h
@@ -86,6 +86,8 @@ struct _is {
    int finalizing;

    struct _ceval_state ceval;
+    // bpo-46070: Even if each PyInterpreterState has a GC state,
+    // _PyGC_GetState() only uses the state of the main interpreter.
    struct _gc_runtime_state gc;

    PyObject *modules;

diff --git a/Include/internal/pycore_object.h b/Include/internal/pycore_object.h
@@ -18,6 +18,16 @@ PyAPI_FUNC(int) _PyDict_CheckConsistency(PyObject *mp, int check_content);
 /* Only private in Python 3.10 and 3.9.8+; public in 3.11 */
 extern PyObject *_PyType_GetQualName(PyTypeObject *type);

+static inline struct _gc_runtime_state*
+_PyGC_GetState(void)
+{
+    // bpo-46070: Even if each PyInterpreterState has a GC state,
+    // _PyGC_GetState() only uses the state of the main interpreter.
+    PyInterpreterState *interp = _PyRuntime.interpreters.main;
+    return &interp->gc;
+}
+
+
 /* Tell the GC to track this object.
 *
 * NB: While the object is tracked by the collector, it must be safe to call the
@@ -42,8 +52,8 @@ static inline void _PyObject_GC_TRACK_impl(const char *filename, int lineno,
                          "object is in generation which is garbage collected",
                          filename, lineno, "_PyObject_GC_TRACK");

-    PyThreadState *tstate = _PyThreadState_GET();
-    PyGC_Head *generation0 = tstate->interp->gc.generation0;
+    struct _gc_runtime_state *state = _PyGC_GetState();
+    PyGC_Head *generation0 = state->generation0;
    PyGC_Head *last = (PyGC_Head*)(generation0->_gc_prev);
    _PyGCHead_SET_NEXT(last, gc);
    _PyGCHead_SET_PREV(gc, last);

diff --git a/Include/internal/pycore_pylifecycle.h b/Include/internal/pycore_pylifecycle.h
@@ -53,7 +53,7 @@ extern PyStatus _Py_HashRandomization_Init(const PyConfig *);
 extern PyStatus _PyTypes_Init(void);
 extern PyStatus _PyTypes_InitSlotDefs(void);
 extern PyStatus _PyImportZip_Init(PyThreadState *tstate);
-extern PyStatus _PyGC_Init(PyThreadState *tstate);
+extern PyStatus _PyGC_Init(void);


 /* Various internal finalizers */
@@ -74,7 +74,7 @@ extern void PyOS_FiniInterrupts(void);
 extern void _PyExc_Fini(void);
 extern void _PyImport_Fini(void);
 extern void _PyImport_Fini2(void);
-extern void _PyGC_Fini(PyThreadState *tstate);
+extern void _PyGC_Fini(void);
 extern void _PyType_Fini(void);
 extern void _Py_HashRandomization_Fini(void);
 extern void _PyUnicode_Fini(PyThreadState *tstate);
@@ -88,7 +88,7 @@ extern void _PyAST_Fini(void);
 extern PyStatus _PyGILState_Init(PyThreadState *tstate);
 extern void _PyGILState_Fini(PyThreadState *tstate);

-PyAPI_FUNC(void) _PyGC_DumpShutdownStats(PyThreadState *tstate);
+PyAPI_FUNC(void) _PyGC_DumpShutdownStats(void);

 PyAPI_FUNC(PyStatus) _Py_PreInitializeFromPyArgv(
    const PyPreConfig *src_config,

diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-01-12-23-13-39.bpo-46070.cQp0eC.rst b/Misc/NEWS.d/next/Core and Builtins/2022-01-12-23-13-39.bpo-46070.cQp0eC.rst
@@ -0,0 +1,3 @@
+Fix a random crash involving subinterpreters on Windows. Revert the change
+which made the gc module state per interpreter: the gc module state is
+shared again by all interpreters. Patch by Victor Stinner.