bpo-39877: _PyRuntimeState.finalizing becomes atomic (GH-18816)
Convert _PyRuntimeState.finalizing field to an atomic variable:
* Rename it to _finalizing
* Change its type to _Py_atomic_address
* Add _PyRuntimeState_GetFinalizing() and _PyRuntimeState_SetFinalizing()
functions
* Remove _Py_CURRENTLY_FINALIZING() function: replace it with testing
directly _PyRuntimeState_GetFinalizing() value
Convert _PyRuntimeState_GetThreadState() to static inline function.
diff --git a/Include/internal/pycore_pystate.h b/Include/internal/pycore_pystate.h
index 405efb9..b5f5095 100644
--- a/Include/internal/pycore_pystate.h
+++ b/Include/internal/pycore_pystate.h
@@ -223,8 +223,11 @@
int initialized;
/* Set by Py_FinalizeEx(). Only reset to NULL if Py_Initialize()
- is called again. */
- PyThreadState *finalizing;
+ is called again.
+
+ Use _PyRuntimeState_GetFinalizing() and _PyRuntimeState_SetFinalizing()
+ to access it, don't access it directly. */
+ _Py_atomic_address _finalizing;
struct pyinterpreters {
PyThread_type_lock mutex;
@@ -279,8 +282,15 @@
PyAPI_FUNC(void) _PyRuntime_Finalize(void);
-#define _Py_CURRENTLY_FINALIZING(runtime, tstate) \
- (runtime->finalizing == tstate)
+static inline PyThreadState*
+_PyRuntimeState_GetFinalizing(_PyRuntimeState *runtime) {
+ return (PyThreadState*)_Py_atomic_load_relaxed(&runtime->_finalizing);
+}
+
+static inline void
+_PyRuntimeState_SetFinalizing(_PyRuntimeState *runtime, PyThreadState *tstate) {
+ _Py_atomic_store_relaxed(&runtime->_finalizing, (uintptr_t)tstate);
+}
PyAPI_FUNC(int) _Py_IsMainInterpreter(PyThreadState* tstate);
@@ -288,8 +298,9 @@
/* Variable and macro for in-line access to current thread
and interpreter state */
-#define _PyRuntimeState_GetThreadState(runtime) \
- ((PyThreadState*)_Py_atomic_load_relaxed(&(runtime)->gilstate.tstate_current))
+static inline PyThreadState* _PyRuntimeState_GetThreadState(_PyRuntimeState *runtime) {
+ return (PyThreadState*)_Py_atomic_load_relaxed(&runtime->gilstate.tstate_current);
+}
/* Get the current Python thread state.
diff --git a/Python/ceval.c b/Python/ceval.c
index ef4aac2..20e32e2 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -240,7 +240,8 @@
{
_PyRuntimeState *runtime = tstate->interp->runtime;
/* _Py_Finalizing is protected by the GIL */
- if (runtime->finalizing != NULL && !_Py_CURRENTLY_FINALIZING(runtime, tstate)) {
+ PyThreadState *finalizing = _PyRuntimeState_GetFinalizing(runtime);
+ if (finalizing != NULL && finalizing != tstate) {
drop_gil(&runtime->ceval, tstate);
PyThread_exit_thread();
}
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index 84ced42..23d74ee 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -103,7 +103,7 @@
int
_Py_IsFinalizing(void)
{
- return _PyRuntime.finalizing != NULL;
+ return _PyRuntimeState_GetFinalizing(&_PyRuntime) != NULL;
}
/* Hack to force loading of object files */
@@ -507,7 +507,7 @@
* threads still hanging around from a previous Py_Initialize/Finalize
* pair :(
*/
- runtime->finalizing = NULL;
+ _PyRuntimeState_SetFinalizing(runtime, NULL);
PyStatus status = _Py_HashRandomization_Init(config);
if (_PyStatus_EXCEPTION(status)) {
@@ -1366,7 +1366,7 @@
/* Remaining threads (e.g. daemon threads) will automatically exit
after taking the GIL (in PyEval_RestoreThread()). */
- runtime->finalizing = tstate;
+ _PyRuntimeState_SetFinalizing(runtime, tstate);
runtime->initialized = 0;
runtime->core_initialized = 0;
@@ -2131,8 +2131,9 @@
fatal_error_dump_runtime(FILE *stream, _PyRuntimeState *runtime)
{
fprintf(stream, "Python runtime state: ");
- if (runtime->finalizing) {
- fprintf(stream, "finalizing (tstate=%p)", runtime->finalizing);
+ PyThreadState *finalizing = _PyRuntimeState_GetFinalizing(runtime);
+ if (finalizing) {
+ fprintf(stream, "finalizing (tstate=%p)", finalizing);
}
else if (runtime->initialized) {
fprintf(stream, "initialized");
diff --git a/Python/pystate.c b/Python/pystate.c
index 4001c63..9002669 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -292,7 +292,7 @@
Py_CLEAR(interp->after_forkers_parent);
Py_CLEAR(interp->after_forkers_child);
#endif
- if (runtime->finalizing == NULL) {
+ if (_PyRuntimeState_GetFinalizing(runtime) == NULL) {
_PyWarnings_Fini(interp);
}
// XXX Once we have one allocator per interpreter (i.e.
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index bfacf31..f086514 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -289,8 +289,9 @@
/* Must be finalizing to clear hooks */
_PyRuntimeState *runtime = &_PyRuntime;
PyThreadState *ts = _PyRuntimeState_GetThreadState(runtime);
- assert(!ts || _Py_CURRENTLY_FINALIZING(runtime, ts));
- if (!ts || !_Py_CURRENTLY_FINALIZING(runtime, ts)) {
+ PyThreadState *finalizing = _PyRuntimeState_GetFinalizing(runtime);
+ assert(!ts || finalizing == ts);
+ if (!ts || finalizing != ts) {
return;
}