From: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Date: Mon, 17 Jun 2024 22:13:40 +0000 (+0200)
Subject: [3.13] gh-120524: Avoid a Race On _PyRuntime.types.managed_static.types[i].interp_cou... 
X-Git-Tag: v3.13.0b3~79
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=71ad34d2190a1f16ac7dbc70b8bce8c6b2549109;p=thirdparty%2FPython%2Fcpython.git

[3.13] gh-120524: Avoid a Race On _PyRuntime.types.managed_static.types[i].interp_count (gh-120657)

gh-120182 added new global state (interp_count), but didn't add thread-safety for it.  This change eliminates the possible race.

(cherry picked from commit 2c66318cdc0545da37e7046533dfe74bde129d91, AKA gh-120529)

Co-authored-by: Eric Snow <ericsnowcurrently@gmail.com>
---

diff --git a/Lib/test/test_interpreters/test_stress.py b/Lib/test/test_interpreters/test_stress.py
index 40d2d77a7b9d..e400535b2a0e 100644
--- a/Lib/test/test_interpreters/test_stress.py
+++ b/Lib/test/test_interpreters/test_stress.py
@@ -22,7 +22,6 @@ class StressTests(TestBase):
             interp = interpreters.create()
             alive.append(interp)
 
-    @unittest.skip('(temporary) gh-120524: there is a race that needs fixing')
     @support.requires_resource('cpu')
     def test_create_many_threaded(self):
         alive = []
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 1123ef6eb3d9..5c490e833739 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -246,7 +246,8 @@ managed_static_type_state_init(PyInterpreterState *interp, PyTypeObject *self,
 
     assert((initial == 1) ==
             (_PyRuntime.types.managed_static.types[full_index].interp_count == 0));
-    _PyRuntime.types.managed_static.types[full_index].interp_count += 1;
+    (void)_Py_atomic_add_int64(
+            &_PyRuntime.types.managed_static.types[full_index].interp_count, 1);
 
     if (initial) {
         assert(_PyRuntime.types.managed_static.types[full_index].type == NULL);
@@ -300,7 +301,8 @@ managed_static_type_state_clear(PyInterpreterState *interp, PyTypeObject *self,
     state->type = NULL;
     assert(state->tp_weaklist == NULL);  // It was already cleared out.
 
-    _PyRuntime.types.managed_static.types[full_index].interp_count -= 1;
+    (void)_Py_atomic_add_int64(
+            &_PyRuntime.types.managed_static.types[full_index].interp_count, -1);
     if (final) {
         assert(!_PyRuntime.types.managed_static.types[full_index].interp_count);
         _PyRuntime.types.managed_static.types[full_index].type = NULL;