From fd3be2998a0325224efb4e69b4dd0b75e3c32b3c Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Tue, 17 Feb 2026 22:24:13 +0900
Subject: [PATCH 01/18] gh-141510: Optimize {frozen}dict.fromkeys for
 frozendict

---
 Objects/dictobject.c | 35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 46b0148cf59ab5..7db60507ef3190 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -3285,7 +3285,7 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
 
 
     if (PyAnyDict_CheckExact(d)) {
-        if (PyAnyDict_CheckExact(iterable)) {
+        if (PyDict_CheckExact(iterable)) {
             PyDictObject *mp = (PyDictObject *)d;
 
             Py_BEGIN_CRITICAL_SECTION2(d, iterable);
@@ -3293,6 +3293,14 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
             Py_END_CRITICAL_SECTION2();
             return d;
         }
+        else if (PyFrozenDict_CheckExact(iterable)) {
+            PyDictObject *mp = (PyDictObject *)d;
+
+            Py_BEGIN_CRITICAL_SECTION(d);
+            d = (PyObject *)dict_dict_fromkeys(mp, iterable, value);
+            Py_END_CRITICAL_SECTION();
+            return d;
+        }
         else if (PyAnySet_CheckExact(iterable)) {
             PyDictObject *mp = (PyDictObject *)d;
 
@@ -3302,6 +3310,29 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
             return d;
         }
     }
+    else if (PyFrozenDict_CheckExact(d)) {
+        if (PyDict_CheckExact(iterable)) {
+            PyDictObject *mp = (PyDictObject *)d;
+
+            Py_BEGIN_CRITICAL_SECTION(iterable);
+            d = (PyObject *)dict_dict_fromkeys(mp, iterable, value);
+            Py_END_CRITICAL_SECTION();
+            return d;
+        }
+        else if (PyFrozenDict_CheckExact(iterable)) {
+            PyDictObject *mp = (PyDictObject *)d;
+            d = (PyObject *)dict_dict_fromkeys(mp, iterable, value);
+            return d;
+        }
+        else if (PyAnySet_CheckExact(iterable)) {
+            PyDictObject *mp = (PyDictObject *)d;
+
+            Py_BEGIN_CRITICAL_SECTION(iterable);
+            d = (PyObject *)dict_set_fromkeys(mp, iterable, value);
+            Py_END_CRITICAL_SECTION();
+            return d;
+        }
+    }
 
     it = PyObject_GetIter(iterable);
     if (it == NULL){
@@ -3309,7 +3340,7 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
         return NULL;
     }
 
-    if (PyAnyDict_CheckExact(d)) {
+    if (PyDict_CheckExact(d)) {
         Py_BEGIN_CRITICAL_SECTION(d);
         while ((key = PyIter_Next(it)) != NULL) {
             status = setitem_lock_held((PyDictObject *)d, key, value);

From 36f2d77ef7d2f1b1a2851e0d8f025524d5603c1e Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Tue, 17 Feb 2026 22:27:19 +0900
Subject: [PATCH 02/18] Add NEWS.d

---
 .../2026-02-17-22-27-11.gh-issue-141510.-4yYsf.rst             | 3 +++
 1 file changed, 3 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Core_and_Builtins/2026-02-17-22-27-11.gh-issue-141510.-4yYsf.rst

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-02-17-22-27-11.gh-issue-141510.-4yYsf.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-02-17-22-27-11.gh-issue-141510.-4yYsf.rst
new file mode 100644
index 00000000000000..78a3e6c63da9a3
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-02-17-22-27-11.gh-issue-141510.-4yYsf.rst
@@ -0,0 +1,3 @@
+Optimize :meth:`dict.fromkeys` and :meth:`frozendict.fromkeys` to avoid
+unnecessary thread-safety operations in frozendict cases. Patch by Donghee
+Na.

From f056fa63076f2fcf6d5ab126f2b45064c03d4747 Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Tue, 17 Feb 2026 22:49:55 +0900
Subject: [PATCH 03/18] Update docs

---
 Doc/library/stdtypes.rst | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst
index 6f798f02e17899..8fabe04ed502aa 100644
--- a/Doc/library/stdtypes.rst
+++ b/Doc/library/stdtypes.rst
@@ -5871,6 +5871,16 @@ Frozen dictionaries
    :class:`!frozendict` is not a :class:`!dict` subclass but inherits directly
    from ``object``.
 
+   .. classmethod:: fromkeys(iterable, value=None, /)
+
+      Create a new frozen dictionary with keys from *iterable* and values set to
+      *value*.
+
+      :meth:`fromkeys` is a class method that returns a new frozen dictionary.
+      *value* defaults to ``None``.  All of the values refer to just a single
+      instance, so it generally doesn't make sense for *value* to be a mutable
+      object such as an empty list.
+
    .. versionadded:: next
 
 

From b51b1aaefe70bb9230d24433da6eddec7840a058 Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Tue, 17 Feb 2026 23:12:54 +0900
Subject: [PATCH 04/18] fix

---
 Objects/dictobject.c | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 7db60507ef3190..1db821dfb1cc4f 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -2671,10 +2671,8 @@ _PyDict_LoadBuiltinsFromGlobals(PyObject *globals)
 
 /* Consumes references to key and value */
 static int
-setitem_take2_lock_held(PyDictObject *mp, PyObject *key, PyObject *value)
+anydict_setitem_take2(PyDictObject *mp, PyObject *key, PyObject *value)
 {
-    ASSERT_DICT_LOCKED(mp);
-
     assert(key);
     assert(value);
     assert(PyAnyDict_Check(mp));
@@ -2693,6 +2691,14 @@ setitem_take2_lock_held(PyDictObject *mp, PyObject *key, PyObject *value)
     return insertdict(mp, key, hash, value);
 }
 
+/* Consumes references to key and value */
+static int
+setitem_take2_lock_held(PyDictObject *mp, PyObject *key, PyObject *value)
+{
+    ASSERT_DICT_LOCKED(mp);
+    return anydict_setitem_take2(mp, key, value);
+}
+
 int
 _PyDict_SetItem_Take2(PyDictObject *mp, PyObject *key, PyObject *value)
 {
@@ -3352,7 +3358,19 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
         }
 dict_iter_exit:;
         Py_END_CRITICAL_SECTION();
-    } else {
+    }
+    else if (PyFrozenDict_CheckExact(d)) {
+        while ((key = PyIter_Next(it)) != NULL) {
+            status = anydict_setitem_take2((PyDictObject *)d,
+                                           Py_NewRef(key), Py_NewRef(value));
+            Py_DECREF(key);
+            if (status < 0) {
+                assert(PyErr_Occurred());
+                goto Fail;
+            }
+        }
+    }
+    else {
         while ((key = PyIter_Next(it)) != NULL) {
             status = PyObject_SetItem(d, key, value);
             Py_DECREF(key);

From a49d630d19777c7d2f038f751c539f4e81e2e722 Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Tue, 17 Feb 2026 23:28:57 +0900
Subject: [PATCH 05/18] Address code review

---
 Objects/dictobject.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 1db821dfb1cc4f..a53e5c18247a1c 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -3290,7 +3290,7 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
         return NULL;
 
 
-    if (PyAnyDict_CheckExact(d)) {
+    if (PyDict_CheckExact(d)) {
         if (PyDict_CheckExact(iterable)) {
             PyDictObject *mp = (PyDictObject *)d;
 

From da588a1f08b874e9a625195509cd914acce98d4a Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Tue, 17 Feb 2026 23:51:15 +0900
Subject: [PATCH 06/18] Address code review

---
 Objects/dictobject.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index a53e5c18247a1c..aef488f4a68c98 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -3362,8 +3362,7 @@ dict_iter_exit:;
     else if (PyFrozenDict_CheckExact(d)) {
         while ((key = PyIter_Next(it)) != NULL) {
             status = anydict_setitem_take2((PyDictObject *)d,
-                                           Py_NewRef(key), Py_NewRef(value));
-            Py_DECREF(key);
+                                           key, Py_NewRef(value));
             if (status < 0) {
                 assert(PyErr_Occurred());
                 goto Fail;

From 49e8a98b697040c7c5f6424c41a1454951d69039 Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Wed, 18 Feb 2026 00:08:47 +0900
Subject: [PATCH 07/18] Address code review

---
 Doc/library/stdtypes.rst                               | 10 ----------
 .../2026-02-17-22-27-11.gh-issue-141510.-4yYsf.rst     |  5 ++---
 2 files changed, 2 insertions(+), 13 deletions(-)

diff --git a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst
index 8fabe04ed502aa..6f798f02e17899 100644
--- a/Doc/library/stdtypes.rst
+++ b/Doc/library/stdtypes.rst
@@ -5871,16 +5871,6 @@ Frozen dictionaries
    :class:`!frozendict` is not a :class:`!dict` subclass but inherits directly
    from ``object``.
 
-   .. classmethod:: fromkeys(iterable, value=None, /)
-
-      Create a new frozen dictionary with keys from *iterable* and values set to
-      *value*.
-
-      :meth:`fromkeys` is a class method that returns a new frozen dictionary.
-      *value* defaults to ``None``.  All of the values refer to just a single
-      instance, so it generally doesn't make sense for *value* to be a mutable
-      object such as an empty list.
-
    .. versionadded:: next
 
 
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-02-17-22-27-11.gh-issue-141510.-4yYsf.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-02-17-22-27-11.gh-issue-141510.-4yYsf.rst
index 78a3e6c63da9a3..b031fb3c75dea7 100644
--- a/Misc/NEWS.d/next/Core_and_Builtins/2026-02-17-22-27-11.gh-issue-141510.-4yYsf.rst
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-02-17-22-27-11.gh-issue-141510.-4yYsf.rst
@@ -1,3 +1,2 @@
-Optimize :meth:`dict.fromkeys` and :meth:`frozendict.fromkeys` to avoid
-unnecessary thread-safety operations in frozendict cases. Patch by Donghee
-Na.
+Optimize :meth:`!frozendict.fromkeys` to avoid unnecessary thread-safety operations
+in frozendict cases. Patch by Donghee Na.

From 8d8fc98b17f3d8c91b494df9171d5073c4b94e95 Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Wed, 18 Feb 2026 00:28:38 +0900
Subject: [PATCH 08/18] Address code review

---
 Objects/dictobject.c | 45 +++-----------------------------------------
 1 file changed, 3 insertions(+), 42 deletions(-)

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index aef488f4a68c98..37b64089a4530c 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -3290,33 +3290,7 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
         return NULL;
 
 
-    if (PyDict_CheckExact(d)) {
-        if (PyDict_CheckExact(iterable)) {
-            PyDictObject *mp = (PyDictObject *)d;
-
-            Py_BEGIN_CRITICAL_SECTION2(d, iterable);
-            d = (PyObject *)dict_dict_fromkeys(mp, iterable, value);
-            Py_END_CRITICAL_SECTION2();
-            return d;
-        }
-        else if (PyFrozenDict_CheckExact(iterable)) {
-            PyDictObject *mp = (PyDictObject *)d;
-
-            Py_BEGIN_CRITICAL_SECTION(d);
-            d = (PyObject *)dict_dict_fromkeys(mp, iterable, value);
-            Py_END_CRITICAL_SECTION();
-            return d;
-        }
-        else if (PyAnySet_CheckExact(iterable)) {
-            PyDictObject *mp = (PyDictObject *)d;
-
-            Py_BEGIN_CRITICAL_SECTION2(d, iterable);
-            d = (PyObject *)dict_set_fromkeys(mp, iterable, value);
-            Py_END_CRITICAL_SECTION2();
-            return d;
-        }
-    }
-    else if (PyFrozenDict_CheckExact(d)) {
+    if (PyAnyDict_CheckExact(d)) {
         if (PyDict_CheckExact(iterable)) {
             PyDictObject *mp = (PyDictObject *)d;
 
@@ -3333,7 +3307,7 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
         else if (PyAnySet_CheckExact(iterable)) {
             PyDictObject *mp = (PyDictObject *)d;
 
-            Py_BEGIN_CRITICAL_SECTION(iterable);
+            Py_BEGIN_CRITICAL_SECTION(d);
             d = (PyObject *)dict_set_fromkeys(mp, iterable, value);
             Py_END_CRITICAL_SECTION();
             return d;
@@ -3346,20 +3320,7 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
         return NULL;
     }
 
-    if (PyDict_CheckExact(d)) {
-        Py_BEGIN_CRITICAL_SECTION(d);
-        while ((key = PyIter_Next(it)) != NULL) {
-            status = setitem_lock_held((PyDictObject *)d, key, value);
-            Py_DECREF(key);
-            if (status < 0) {
-                assert(PyErr_Occurred());
-                goto dict_iter_exit;
-            }
-        }
-dict_iter_exit:;
-        Py_END_CRITICAL_SECTION();
-    }
-    else if (PyFrozenDict_CheckExact(d)) {
+    if (PyAnyDict_CheckExact(d)) {
         while ((key = PyIter_Next(it)) != NULL) {
             status = anydict_setitem_take2((PyDictObject *)d,
                                            key, Py_NewRef(value));

From fa2505a082b657d4314356d5127173b8e7af492a Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Wed, 18 Feb 2026 00:30:33 +0900
Subject: [PATCH 09/18] nit

---
 Objects/dictobject.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 37b64089a4530c..c743d1d2eb858d 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -3322,8 +3322,7 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
 
     if (PyAnyDict_CheckExact(d)) {
         while ((key = PyIter_Next(it)) != NULL) {
-            status = anydict_setitem_take2((PyDictObject *)d,
-                                           key, Py_NewRef(value));
+            status = anydict_setitem_take2((PyDictObject *)d, key, Py_NewRef(value));
             if (status < 0) {
                 assert(PyErr_Occurred());
                 goto Fail;

From fcef217f450bb5833f3bcd30e8c0b20de81559c8 Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Wed, 18 Feb 2026 00:49:14 +0900
Subject: [PATCH 10/18] fix

---
 Objects/dictobject.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index c743d1d2eb858d..4fa22410840ab0 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -3307,7 +3307,7 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
         else if (PyAnySet_CheckExact(iterable)) {
             PyDictObject *mp = (PyDictObject *)d;
 
-            Py_BEGIN_CRITICAL_SECTION(d);
+            Py_BEGIN_CRITICAL_SECTION(iterable);
             d = (PyObject *)dict_set_fromkeys(mp, iterable, value);
             Py_END_CRITICAL_SECTION();
             return d;

From 0e7021703ce34fe9f2228696c373a746c8a00f16 Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Wed, 18 Feb 2026 01:12:28 +0900
Subject: [PATCH 11/18] fix

---
 Objects/dictobject.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 4fa22410840ab0..a91dcdbf62af68 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -1899,8 +1899,6 @@ insertdict(PyDictObject *mp,
     PyObject *old_value = NULL;
     Py_ssize_t ix;
 
-    ASSERT_DICT_LOCKED(mp);
-
     if (_PyDict_HasSplitTable(mp) && PyUnicode_CheckExact(key)) {
         ix = insert_split_key(mp->ma_keys, key, hash);
         if (ix != DKIX_EMPTY) {
@@ -1968,7 +1966,6 @@ insert_to_emptydict(PyDictObject *mp,
                     PyObject *key, Py_hash_t hash, PyObject *value)
 {
     assert(mp->ma_keys == Py_EMPTY_KEYS);
-    ASSERT_DICT_LOCKED(mp);
 
     int unicode = PyUnicode_CheckExact(key);
     PyDictKeysObject *newkeys = new_keys_object(PyDict_LOG_MINSIZE, unicode);
@@ -2752,6 +2749,7 @@ int
 _PyDict_SetItem_KnownHash_LockHeld(PyDictObject *mp, PyObject *key, PyObject *value,
                                    Py_hash_t hash)
 {
+    ASSERT_DICT_LOCKED(mp);
     if (mp->ma_keys == Py_EMPTY_KEYS) {
         return insert_to_emptydict(mp, Py_NewRef(key), hash, Py_NewRef(value));
     }

From 305b2ef30415029b2fbbf8c3e059b09646db7b89 Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Wed, 18 Feb 2026 01:31:07 +0900
Subject: [PATCH 12/18] fix

---
 Objects/dictobject.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index a91dcdbf62af68..4ec6263aeeec42 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -2069,8 +2069,6 @@ dictresize(PyDictObject *mp,
     PyDictKeysObject *oldkeys, *newkeys;
     PyDictValues *oldvalues;
 
-    ASSERT_DICT_LOCKED(mp);
-
     if (log2_newsize >= SIZEOF_SIZE_T*8) {
         PyErr_NoMemory();
         return -1;

From 0a1b4004ef5ec20ddff3a89affdfc8a26b511572 Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Wed, 18 Feb 2026 01:59:04 +0900
Subject: [PATCH 13/18] Revert "fix"

This reverts commit 305b2ef30415029b2fbbf8c3e059b09646db7b89.
---
 Objects/dictobject.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 4ec6263aeeec42..a91dcdbf62af68 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -2069,6 +2069,8 @@ dictresize(PyDictObject *mp,
     PyDictKeysObject *oldkeys, *newkeys;
     PyDictValues *oldvalues;
 
+    ASSERT_DICT_LOCKED(mp);
+
     if (log2_newsize >= SIZEOF_SIZE_T*8) {
         PyErr_NoMemory();
         return -1;

From 5e2757507bdcc0e1301e58b67f37686e9801ac57 Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Wed, 18 Feb 2026 01:59:16 +0900
Subject: [PATCH 14/18] Revert "fix"

This reverts commit 0e7021703ce34fe9f2228696c373a746c8a00f16.
---
 Objects/dictobject.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index a91dcdbf62af68..4fa22410840ab0 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -1899,6 +1899,8 @@ insertdict(PyDictObject *mp,
     PyObject *old_value = NULL;
     Py_ssize_t ix;
 
+    ASSERT_DICT_LOCKED(mp);
+
     if (_PyDict_HasSplitTable(mp) && PyUnicode_CheckExact(key)) {
         ix = insert_split_key(mp->ma_keys, key, hash);
         if (ix != DKIX_EMPTY) {
@@ -1966,6 +1968,7 @@ insert_to_emptydict(PyDictObject *mp,
                     PyObject *key, Py_hash_t hash, PyObject *value)
 {
     assert(mp->ma_keys == Py_EMPTY_KEYS);
+    ASSERT_DICT_LOCKED(mp);
 
     int unicode = PyUnicode_CheckExact(key);
     PyDictKeysObject *newkeys = new_keys_object(PyDict_LOG_MINSIZE, unicode);
@@ -2749,7 +2752,6 @@ int
 _PyDict_SetItem_KnownHash_LockHeld(PyDictObject *mp, PyObject *key, PyObject *value,
                                    Py_hash_t hash)
 {
-    ASSERT_DICT_LOCKED(mp);
     if (mp->ma_keys == Py_EMPTY_KEYS) {
         return insert_to_emptydict(mp, Py_NewRef(key), hash, Py_NewRef(value));
     }

From 6c8d856c3dba25f49561f1f0ccedd9c9b7019234 Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Wed, 18 Feb 2026 01:59:28 +0900
Subject: [PATCH 15/18] Revert "fix"

This reverts commit fcef217f450bb5833f3bcd30e8c0b20de81559c8.
---
 Objects/dictobject.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 4fa22410840ab0..c743d1d2eb858d 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -3307,7 +3307,7 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
         else if (PyAnySet_CheckExact(iterable)) {
             PyDictObject *mp = (PyDictObject *)d;
 
-            Py_BEGIN_CRITICAL_SECTION(iterable);
+            Py_BEGIN_CRITICAL_SECTION(d);
             d = (PyObject *)dict_set_fromkeys(mp, iterable, value);
             Py_END_CRITICAL_SECTION();
             return d;

From 26c46c7fff515a8e85c718ae613a466c3c3db92b Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Wed, 18 Feb 2026 01:59:49 +0900
Subject: [PATCH 16/18] Revert "nit"

This reverts commit fa2505a082b657d4314356d5127173b8e7af492a.
---
 Objects/dictobject.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index c743d1d2eb858d..37b64089a4530c 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -3322,7 +3322,8 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
 
     if (PyAnyDict_CheckExact(d)) {
         while ((key = PyIter_Next(it)) != NULL) {
-            status = anydict_setitem_take2((PyDictObject *)d, key, Py_NewRef(value));
+            status = anydict_setitem_take2((PyDictObject *)d,
+                                           key, Py_NewRef(value));
             if (status < 0) {
                 assert(PyErr_Occurred());
                 goto Fail;

From d2fb5a068dd4da6cb745a2b2d7363a400c544785 Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Wed, 18 Feb 2026 02:00:04 +0900
Subject: [PATCH 17/18] Revert "Address code review"

This reverts commit 8d8fc98b17f3d8c91b494df9171d5073c4b94e95.
---
 Objects/dictobject.c | 45 +++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 42 insertions(+), 3 deletions(-)

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 37b64089a4530c..aef488f4a68c98 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -3290,7 +3290,33 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
         return NULL;
 
 
-    if (PyAnyDict_CheckExact(d)) {
+    if (PyDict_CheckExact(d)) {
+        if (PyDict_CheckExact(iterable)) {
+            PyDictObject *mp = (PyDictObject *)d;
+
+            Py_BEGIN_CRITICAL_SECTION2(d, iterable);
+            d = (PyObject *)dict_dict_fromkeys(mp, iterable, value);
+            Py_END_CRITICAL_SECTION2();
+            return d;
+        }
+        else if (PyFrozenDict_CheckExact(iterable)) {
+            PyDictObject *mp = (PyDictObject *)d;
+
+            Py_BEGIN_CRITICAL_SECTION(d);
+            d = (PyObject *)dict_dict_fromkeys(mp, iterable, value);
+            Py_END_CRITICAL_SECTION();
+            return d;
+        }
+        else if (PyAnySet_CheckExact(iterable)) {
+            PyDictObject *mp = (PyDictObject *)d;
+
+            Py_BEGIN_CRITICAL_SECTION2(d, iterable);
+            d = (PyObject *)dict_set_fromkeys(mp, iterable, value);
+            Py_END_CRITICAL_SECTION2();
+            return d;
+        }
+    }
+    else if (PyFrozenDict_CheckExact(d)) {
         if (PyDict_CheckExact(iterable)) {
             PyDictObject *mp = (PyDictObject *)d;
 
@@ -3307,7 +3333,7 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
         else if (PyAnySet_CheckExact(iterable)) {
             PyDictObject *mp = (PyDictObject *)d;
 
-            Py_BEGIN_CRITICAL_SECTION(d);
+            Py_BEGIN_CRITICAL_SECTION(iterable);
             d = (PyObject *)dict_set_fromkeys(mp, iterable, value);
             Py_END_CRITICAL_SECTION();
             return d;
@@ -3320,7 +3346,20 @@ _PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)
         return NULL;
     }
 
-    if (PyAnyDict_CheckExact(d)) {
+    if (PyDict_CheckExact(d)) {
+        Py_BEGIN_CRITICAL_SECTION(d);
+        while ((key = PyIter_Next(it)) != NULL) {
+            status = setitem_lock_held((PyDictObject *)d, key, value);
+            Py_DECREF(key);
+            if (status < 0) {
+                assert(PyErr_Occurred());
+                goto dict_iter_exit;
+            }
+        }
+dict_iter_exit:;
+        Py_END_CRITICAL_SECTION();
+    }
+    else if (PyFrozenDict_CheckExact(d)) {
         while ((key = PyIter_Next(it)) != NULL) {
             status = anydict_setitem_take2((PyDictObject *)d,
                                            key, Py_NewRef(value));

From e7c7dffe40470699889aec97cb109a76abb0a934 Mon Sep 17 00:00:00 2001
From: Donghee Na <donghee.na@python.org>
Date: Wed, 18 Feb 2026 06:17:20 +0900
Subject: [PATCH 18/18] Address code review

---
 Objects/dictobject.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index aef488f4a68c98..1c61db68b385a0 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -3361,6 +3361,7 @@ dict_iter_exit:;
     }
     else if (PyFrozenDict_CheckExact(d)) {
         while ((key = PyIter_Next(it)) != NULL) {
+            // anydict_setitem_take2 consumes a reference to key
             status = anydict_setitem_take2((PyDictObject *)d,
                                            key, Py_NewRef(value));
             if (status < 0) {