From: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Date: Mon, 30 Sep 2024 20:51:24 +0000 (+0200)
Subject: [3.13] gh-124642: Dictionaries aren't marking objects as weakref'd (GH-124643) (... 
X-Git-Tag: v3.13.0rc3~6
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=44ba11a2045a8d00b6089fedd8b57f02c8a7225a;p=thirdparty%2FPython%2Fcpython.git

[3.13] gh-124642: Dictionaries aren't marking objects as weakref'd (GH-124643) (#124798)

gh-124642: Dictionaries aren't marking objects as weakref'd (GH-124643)

Dictionaries aren't marking objects as weakref'd
(cherry picked from commit 077e7ef6a0abbf9e04b9aa11b4f621031004c31f)

Co-authored-by: Dino Viehland <dinoviehland@meta.com>
---

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2024-09-27-17-18-53.gh-issue-124642.OCjhBJ.rst b/Misc/NEWS.d/next/Core_and_Builtins/2024-09-27-17-18-53.gh-issue-124642.OCjhBJ.rst
new file mode 100644
index 000000000000..29763844a9f5
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2024-09-27-17-18-53.gh-issue-124642.OCjhBJ.rst
@@ -0,0 +1 @@
+Fixed scalability issue in free-threaded builds for lock-free reads from dictionaries in multi-threaded scenarios
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 7f7fd836c015..a5a5bce39655 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -1549,7 +1549,7 @@ read_failed:
     *value_addr = value;
     if (value != NULL) {
         assert(ix >= 0);
-        Py_INCREF(value);
+        _Py_NewRefWithLock(value);
     }
     Py_END_CRITICAL_SECTION();
     return ix;
@@ -6988,7 +6988,7 @@ _PyObject_TryGetInstanceAttribute(PyObject *obj, PyObject *name, PyObject **attr
             // Still no dict, we can read from the values
             assert(values->valid);
             value = values->values[ix];
-            *attr = Py_XNewRef(value);
+            *attr = _Py_XNewRefWithLock(value);
             success = true;
         }
 
@@ -7008,7 +7008,7 @@ _PyObject_TryGetInstanceAttribute(PyObject *obj, PyObject *name, PyObject **attr
 
     if (dict->ma_values == values && FT_ATOMIC_LOAD_UINT8(values->valid)) {
         value = _Py_atomic_load_ptr_relaxed(&values->values[ix]);
-        *attr = Py_XNewRef(value);
+        *attr = _Py_XNewRefWithLock(value);
         success = true;
     } else {
         // Caller needs to lookup from the dictionary