diff --git a/Include/cpython/dictobject.h b/Include/cpython/dictobject.h
index 35b6a822a0dfffd..3fd23b9313c4536 100644
--- a/Include/cpython/dictobject.h
+++ b/Include/cpython/dictobject.h
@@ -56,7 +56,11 @@ static inline Py_ssize_t PyDict_GET_SIZE(PyObject *op) {
     PyDictObject *mp;
     assert(PyDict_Check(op));
     mp = _Py_CAST(PyDictObject*, op);
+#ifdef Py_GIL_DISABLED
+    return _Py_atomic_load_ssize_relaxed(&mp->ma_used);
+#else
     return mp->ma_used;
+#endif
 }
 #define PyDict_GET_SIZE(op) PyDict_GET_SIZE(_PyObject_CAST(op))
 
diff --git a/Include/cpython/funcobject.h b/Include/cpython/funcobject.h
index de2013323d2c720..5433ba48eefc692 100644
--- a/Include/cpython/funcobject.h
+++ b/Include/cpython/funcobject.h
@@ -8,7 +8,7 @@ extern "C" {
 #endif
 
 
-#define COMMON_FIELDS(PREFIX) \
+#define _Py_COMMON_FIELDS(PREFIX) \
     PyObject *PREFIX ## globals; \
     PyObject *PREFIX ## builtins; \
     PyObject *PREFIX ## name; \
@@ -19,7 +19,7 @@ extern "C" {
     PyObject *PREFIX ## closure;     /* NULL or a tuple of cell objects */
 
 typedef struct {
-    COMMON_FIELDS(fc_)
+    _Py_COMMON_FIELDS(fc_)
 } PyFrameConstructor;
 
 /* Function objects and code objects should not be confused with each other:
@@ -35,7 +35,7 @@ typedef struct {
 
 typedef struct {
     PyObject_HEAD
-    COMMON_FIELDS(func_)
+    _Py_COMMON_FIELDS(func_)
     PyObject *func_doc;         /* The __doc__ attribute, can be anything */
     PyObject *func_dict;        /* The __dict__ attribute, a dict or NULL */
     PyObject *func_weakreflist; /* List of weak references */
@@ -60,6 +60,8 @@ typedef struct {
      */
 } PyFunctionObject;
 
+#undef _Py_COMMON_FIELDS
+
 PyAPI_DATA(PyTypeObject) PyFunction_Type;
 
 #define PyFunction_Check(op) Py_IS_TYPE((op), &PyFunction_Type)
diff --git a/Include/internal/pycore_ceval.h b/Include/internal/pycore_ceval.h
index 946f82ae3c20e38..8d88b5c1d15cb84 100644
--- a/Include/internal/pycore_ceval.h
+++ b/Include/internal/pycore_ceval.h
@@ -182,7 +182,7 @@ static inline void _Py_LeaveRecursiveCall(void)  {
 
 extern struct _PyInterpreterFrame* _PyEval_GetFrame(void);
 
-extern PyObject* _Py_MakeCoro(PyFunctionObject *func);
+PyAPI_FUNC(PyObject *)_Py_MakeCoro(PyFunctionObject *func);
 
 /* Handle signals, pending calls, GIL drop request
    and asynchronous exception */
diff --git a/Include/internal/pycore_fileutils.h b/Include/internal/pycore_fileutils.h
index 5c55282fa39e6f6..bc8100b58e8ea32 100644
--- a/Include/internal/pycore_fileutils.h
+++ b/Include/internal/pycore_fileutils.h
@@ -290,6 +290,8 @@ extern wchar_t *_Py_normpath_and_size(wchar_t *path, Py_ssize_t size, Py_ssize_t
 extern HRESULT PathCchSkipRoot(const wchar_t *pszPath, const wchar_t **ppszRootEnd);
 #endif /* defined(MS_WINDOWS_GAMES) && !defined(MS_WINDOWS_DESKTOP) */
 
+extern void _Py_skiproot(const wchar_t *path, Py_ssize_t size, Py_ssize_t *drvsize, Py_ssize_t *rootsize);
+
 // Macros to protect CRT calls against instant termination when passed an
 // invalid parameter (bpo-23524). IPH stands for Invalid Parameter Handler.
 // Usage:
diff --git a/Include/internal/pycore_frame.h b/Include/internal/pycore_frame.h
index 74d9e4cac72c0e9..f913928f38bd058 100644
--- a/Include/internal/pycore_frame.h
+++ b/Include/internal/pycore_frame.h
@@ -110,7 +110,17 @@ _PyFrame_NumSlotsForCodeObject(PyCodeObject *code)
     return code->co_framesize - FRAME_SPECIALS_SIZE;
 }
 
-void _PyFrame_Copy(_PyInterpreterFrame *src, _PyInterpreterFrame *dest);
+static inline void _PyFrame_Copy(_PyInterpreterFrame *src, _PyInterpreterFrame *dest)
+{
+    assert(src->stacktop >= _PyFrame_GetCode(src)->co_nlocalsplus);
+    *dest = *src;
+    for (int i = 1; i < src->stacktop; i++) {
+        dest->localsplus[i] = src->localsplus[i];
+    }
+    // Don't leave a dangling pointer to the old frame when creating generators
+    // and coroutines:
+    dest->previous = NULL;
+}
 
 /* Consumes reference to func and locals.
    Does not initialize frame->previous, which happens
@@ -256,7 +266,7 @@ _PyThreadState_HasStackSpace(PyThreadState *tstate, int size)
 extern _PyInterpreterFrame *
 _PyThreadState_PushFrame(PyThreadState *tstate, size_t size);
 
-void _PyThreadState_PopFrame(PyThreadState *tstate, _PyInterpreterFrame *frame);
+PyAPI_FUNC(void) _PyThreadState_PopFrame(PyThreadState *tstate, _PyInterpreterFrame *frame);
 
 /* Pushes a frame without checking for space.
  * Must be guarded by _PyThreadState_HasStackSpace()
diff --git a/Include/internal/pycore_object.h b/Include/internal/pycore_object.h
index 88b052f4544b155..7df8003196d8cc0 100644
--- a/Include/internal/pycore_object.h
+++ b/Include/internal/pycore_object.h
@@ -688,7 +688,7 @@ static inline PyDictObject *
 _PyObject_GetManagedDict(PyObject *obj)
 {
     PyManagedDictPointer *dorv = _PyObject_ManagedDictPointer(obj);
-    return (PyDictObject *)FT_ATOMIC_LOAD_PTR_RELAXED(dorv->dict);
+    return (PyDictObject *)FT_ATOMIC_LOAD_PTR_ACQUIRE(dorv->dict);
 }
 
 static inline PyDictValues *
diff --git a/Include/internal/pycore_opcode_metadata.h b/Include/internal/pycore_opcode_metadata.h
index 5636debbf4a7f2c..400d7c334db8e73 100644
--- a/Include/internal/pycore_opcode_metadata.h
+++ b/Include/internal/pycore_opcode_metadata.h
@@ -805,7 +805,7 @@ int _PyOpcode_num_pushed(int opcode, int oparg)  {
         case RETURN_CONST:
             return 0;
         case RETURN_GENERATOR:
-            return 0;
+            return 1;
         case RETURN_VALUE:
             return 0;
         case SEND:
@@ -1310,6 +1310,7 @@ _PyOpcode_macro_expansion[256] = {
     [PUSH_NULL] = { .nuops = 1, .uops = { { _PUSH_NULL, 0, 0 } } },
     [RESUME_CHECK] = { .nuops = 1, .uops = { { _RESUME_CHECK, 0, 0 } } },
     [RETURN_CONST] = { .nuops = 2, .uops = { { _LOAD_CONST, 0, 0 }, { _POP_FRAME, 0, 0 } } },
+    [RETURN_GENERATOR] = { .nuops = 1, .uops = { { _RETURN_GENERATOR, 0, 0 } } },
     [RETURN_VALUE] = { .nuops = 1, .uops = { { _POP_FRAME, 0, 0 } } },
     [SETUP_ANNOTATIONS] = { .nuops = 1, .uops = { { _SETUP_ANNOTATIONS, 0, 0 } } },
     [SET_ADD] = { .nuops = 1, .uops = { { _SET_ADD, 0, 0 } } },
diff --git a/Include/internal/pycore_typeobject.h b/Include/internal/pycore_typeobject.h
index 09c4501c38c935c..7e533bd138469ba 100644
--- a/Include/internal/pycore_typeobject.h
+++ b/Include/internal/pycore_typeobject.h
@@ -164,6 +164,7 @@ extern PyObject * _PyType_GetBases(PyTypeObject *type);
 extern PyObject * _PyType_GetMRO(PyTypeObject *type);
 extern PyObject* _PyType_GetSubclasses(PyTypeObject *);
 extern int _PyType_HasSubclasses(PyTypeObject *);
+PyAPI_FUNC(PyObject *) _PyType_GetModuleByDef2(PyTypeObject *, PyTypeObject *, PyModuleDef *);
 
 // PyType_Ready() must be called if _PyType_IsReady() is false.
 // See also the Py_TPFLAGS_READY flag.
diff --git a/Include/internal/pycore_uop_ids.h b/Include/internal/pycore_uop_ids.h
index f0558743b32f5e7..bb49d6e77d25622 100644
--- a/Include/internal/pycore_uop_ids.h
+++ b/Include/internal/pycore_uop_ids.h
@@ -231,6 +231,7 @@ extern "C" {
 #define _PUSH_NULL PUSH_NULL
 #define _REPLACE_WITH_TRUE 424
 #define _RESUME_CHECK RESUME_CHECK
+#define _RETURN_GENERATOR RETURN_GENERATOR
 #define _SAVE_RETURN_OFFSET 425
 #define _SEND 426
 #define _SEND_GEN SEND_GEN
diff --git a/Include/internal/pycore_uop_metadata.h b/Include/internal/pycore_uop_metadata.h
index 2da4c4d4e21e939..b8cdfae83914603 100644
--- a/Include/internal/pycore_uop_metadata.h
+++ b/Include/internal/pycore_uop_metadata.h
@@ -219,6 +219,7 @@ const uint16_t _PyUop_Flags[MAX_UOP_ID+1] = {
     [_CALL_METHOD_DESCRIPTOR_FAST] = HAS_ARG_FLAG | HAS_DEOPT_FLAG | HAS_ERROR_FLAG | HAS_ESCAPES_FLAG,
     [_MAKE_FUNCTION] = HAS_ERROR_FLAG | HAS_ERROR_NO_POP_FLAG | HAS_ESCAPES_FLAG,
     [_SET_FUNCTION_ATTRIBUTE] = HAS_ARG_FLAG | HAS_ESCAPES_FLAG,
+    [_RETURN_GENERATOR] = HAS_ERROR_FLAG | HAS_ERROR_NO_POP_FLAG | HAS_ESCAPES_FLAG,
     [_BUILD_SLICE] = HAS_ARG_FLAG | HAS_ERROR_FLAG,
     [_CONVERT_VALUE] = HAS_ARG_FLAG | HAS_ERROR_FLAG,
     [_FORMAT_SIMPLE] = HAS_ERROR_FLAG | HAS_ESCAPES_FLAG,
@@ -445,6 +446,7 @@ const char *const _PyOpcode_uop_name[MAX_UOP_ID+1] = {
     [_PUSH_NULL] = "_PUSH_NULL",
     [_REPLACE_WITH_TRUE] = "_REPLACE_WITH_TRUE",
     [_RESUME_CHECK] = "_RESUME_CHECK",
+    [_RETURN_GENERATOR] = "_RETURN_GENERATOR",
     [_SAVE_RETURN_OFFSET] = "_SAVE_RETURN_OFFSET",
     [_SETUP_ANNOTATIONS] = "_SETUP_ANNOTATIONS",
     [_SET_ADD] = "_SET_ADD",
@@ -894,6 +896,8 @@ int _PyUop_num_popped(int opcode, int oparg)
             return 1;
         case _SET_FUNCTION_ATTRIBUTE:
             return 2;
+        case _RETURN_GENERATOR:
+            return 0;
         case _BUILD_SLICE:
             return 2 + ((oparg == 3) ? 1 : 0);
         case _CONVERT_VALUE:
diff --git a/Include/object.h b/Include/object.h
index ffcacf1a3ef4ed9..5aaf11c5194f0e3 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -349,7 +349,8 @@ static inline Py_ssize_t Py_SIZE(PyObject *ob) {
 static inline Py_ALWAYS_INLINE int _Py_IsImmortal(PyObject *op)
 {
 #if defined(Py_GIL_DISABLED)
-    return (op->ob_ref_local == _Py_IMMORTAL_REFCNT_LOCAL);
+    return (_Py_atomic_load_uint32_relaxed(&op->ob_ref_local) ==
+            _Py_IMMORTAL_REFCNT_LOCAL);
 #elif SIZEOF_VOID_P > 4
     return (_Py_CAST(PY_INT32_T, op->ob_refcnt) < 0);
 #else
diff --git a/Lib/ipaddress.py b/Lib/ipaddress.py
index 22cdfc93d8ad32d..8e4d49c859534d8 100644
--- a/Lib/ipaddress.py
+++ b/Lib/ipaddress.py
@@ -2142,6 +2142,9 @@ def is_loopback(self):
             RFC 2373 2.5.3.
 
         """
+        ipv4_mapped = self.ipv4_mapped
+        if ipv4_mapped is not None:
+            return ipv4_mapped.is_loopback
         return self._ip == 1
 
     @property
@@ -2258,7 +2261,7 @@ def is_unspecified(self):
 
     @property
     def is_loopback(self):
-        return self._ip == 1 and self.network.is_loopback
+        return super().is_loopback and self.network.is_loopback
 
 
 class IPv6Network(_BaseV6, _BaseNetwork):
diff --git a/Lib/ntpath.py b/Lib/ntpath.py
index 7e5516eeccbe0bd..56b08f4c7234aa5 100644
--- a/Lib/ntpath.py
+++ b/Lib/ntpath.py
@@ -167,56 +167,76 @@ def splitdrive(p):
     return drive, root + tail
 
 
-def splitroot(p):
-    """Split a pathname into drive, root and tail. The drive is defined
-    exactly as in splitdrive(). On Windows, the root may be a single path
-    separator or an empty string. The tail contains anything after the root.
-    For example:
-
-        splitroot('//server/share/') == ('//server/share', '/', '')
-        splitroot('C:/Users/Barney') == ('C:', '/', 'Users/Barney')
-        splitroot('C:///spam///ham') == ('C:', '/', '//spam///ham')
-        splitroot('Windows/notepad') == ('', '', 'Windows/notepad')
-    """
-    p = os.fspath(p)
-    if isinstance(p, bytes):
-        sep = b'\\'
-        altsep = b'/'
-        colon = b':'
-        unc_prefix = b'\\\\?\\UNC\\'
-        empty = b''
-    else:
-        sep = '\\'
-        altsep = '/'
-        colon = ':'
-        unc_prefix = '\\\\?\\UNC\\'
-        empty = ''
-    normp = p.replace(altsep, sep)
-    if normp[:1] == sep:
-        if normp[1:2] == sep:
-            # UNC drives, e.g. \\server\share or \\?\UNC\server\share
-            # Device drives, e.g. \\.\device or \\?\device
-            start = 8 if normp[:8].upper() == unc_prefix else 2
-            index = normp.find(sep, start)
-            if index == -1:
-                return p, empty, empty
-            index2 = normp.find(sep, index + 1)
-            if index2 == -1:
-                return p, empty, empty
-            return p[:index2], p[index2:index2 + 1], p[index2 + 1:]
+try:
+    from nt import _path_splitroot_ex
+except ImportError:
+    def splitroot(p):
+        """Split a pathname into drive, root and tail. The drive is defined
+        exactly as in splitdrive(). On Windows, the root may be a single path
+        separator or an empty string. The tail contains anything after the root.
+        For example:
+
+            splitroot('//server/share/') == ('//server/share', '/', '')
+            splitroot('C:/Users/Barney') == ('C:', '/', 'Users/Barney')
+            splitroot('C:///spam///ham') == ('C:', '/', '//spam///ham')
+            splitroot('Windows/notepad') == ('', '', 'Windows/notepad')
+        """
+        p = os.fspath(p)
+        if isinstance(p, bytes):
+            sep = b'\\'
+            altsep = b'/'
+            colon = b':'
+            unc_prefix = b'\\\\?\\UNC\\'
+            empty = b''
         else:
-            # Relative path with root, e.g. \Windows
-            return empty, p[:1], p[1:]
-    elif normp[1:2] == colon:
-        if normp[2:3] == sep:
-            # Absolute drive-letter path, e.g. X:\Windows
-            return p[:2], p[2:3], p[3:]
+            sep = '\\'
+            altsep = '/'
+            colon = ':'
+            unc_prefix = '\\\\?\\UNC\\'
+            empty = ''
+        normp = p.replace(altsep, sep)
+        if normp[:1] == sep:
+            if normp[1:2] == sep:
+                # UNC drives, e.g. \\server\share or \\?\UNC\server\share
+                # Device drives, e.g. \\.\device or \\?\device
+                start = 8 if normp[:8].upper() == unc_prefix else 2
+                index = normp.find(sep, start)
+                if index == -1:
+                    return p, empty, empty
+                index2 = normp.find(sep, index + 1)
+                if index2 == -1:
+                    return p, empty, empty
+                return p[:index2], p[index2:index2 + 1], p[index2 + 1:]
+            else:
+                # Relative path with root, e.g. \Windows
+                return empty, p[:1], p[1:]
+        elif normp[1:2] == colon:
+            if normp[2:3] == sep:
+                # Absolute drive-letter path, e.g. X:\Windows
+                return p[:2], p[2:3], p[3:]
+            else:
+                # Relative path with drive, e.g. X:Windows
+                return p[:2], empty, p[2:]
         else:
-            # Relative path with drive, e.g. X:Windows
-            return p[:2], empty, p[2:]
-    else:
-        # Relative path, e.g. Windows
-        return empty, empty, p
+            # Relative path, e.g. Windows
+            return empty, empty, p
+else:
+    def splitroot(p):
+        """Split a pathname into drive, root and tail. The drive is defined
+        exactly as in splitdrive(). On Windows, the root may be a single path
+        separator or an empty string. The tail contains anything after the root.
+        For example:
+
+            splitroot('//server/share/') == ('//server/share', '/', '')
+            splitroot('C:/Users/Barney') == ('C:', '/', 'Users/Barney')
+            splitroot('C:///spam///ham') == ('C:', '/', '//spam///ham')
+            splitroot('Windows/notepad') == ('', '', 'Windows/notepad')
+        """
+        p = os.fspath(p)
+        if isinstance(p, bytes):
+            drive, root, tail = _path_splitroot_ex(os.fsdecode(p))
+            return os.fsencode(drive), os.fsencode(root), os.fsencode(tail)
+        return _path_splitroot_ex(p)
 
 
 # Split a path in head (everything up to the last '/') and tail (the
diff --git a/Lib/posixpath.py b/Lib/posixpath.py
index f1960ddb88e5905..56b7915826daf4b 100644
--- a/Lib/posixpath.py
+++ b/Lib/posixpath.py
@@ -134,33 +134,53 @@ def splitdrive(p):
     return p[:0], p
 
 
-def splitroot(p):
-    """Split a pathname into drive, root and tail. On Posix, drive is always
-    empty; the root may be empty, a single slash, or two slashes. The tail
-    contains anything after the root. For example:
-
-        splitroot('foo/bar') == ('', '', 'foo/bar')
-        splitroot('/foo/bar') == ('', '/', 'foo/bar')
-        splitroot('//foo/bar') == ('', '//', 'foo/bar')
-        splitroot('///foo/bar') == ('', '/', '//foo/bar')
-    """
-    p = os.fspath(p)
-    if isinstance(p, bytes):
-        sep = b'/'
-        empty = b''
-    else:
-        sep = '/'
-        empty = ''
-    if p[:1] != sep:
-        # Relative path, e.g.: 'foo'
-        return empty, empty, p
-    elif p[1:2] != sep or p[2:3] == sep:
-        # Absolute path, e.g.: '/foo', '///foo', '////foo', etc.
-        return empty, sep, p[1:]
-    else:
-        # Precisely two leading slashes, e.g.: '//foo'. Implementation defined per POSIX, see
-        # https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13
-        return empty, p[:2], p[2:]
+try:
+    from posix import _path_splitroot_ex
+except ImportError:
+    def splitroot(p):
+        """Split a pathname into drive, root and tail. On Posix, drive is always
+        empty; the root may be empty, a single slash, or two slashes. The tail
+        contains anything after the root. For example:
+
+            splitroot('foo/bar') == ('', '', 'foo/bar')
+            splitroot('/foo/bar') == ('', '/', 'foo/bar')
+            splitroot('//foo/bar') == ('', '//', 'foo/bar')
+            splitroot('///foo/bar') == ('', '/', '//foo/bar')
+        """
+        p = os.fspath(p)
+        if isinstance(p, bytes):
+            sep = b'/'
+            empty = b''
+        else:
+            sep = '/'
+            empty = ''
+        if p[:1] != sep:
+            # Relative path, e.g.: 'foo'
+            return empty, empty, p
+        elif p[1:2] != sep or p[2:3] == sep:
+            # Absolute path, e.g.: '/foo', '///foo', '////foo', etc.
+            return empty, sep, p[1:]
+        else:
+            # Precisely two leading slashes, e.g.: '//foo'. Implementation defined per POSIX, see
+            # https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13
+            return empty, p[:2], p[2:]
+else:
+    def splitroot(p):
+        """Split a pathname into drive, root and tail. On Posix, drive is always
+        empty; the root may be empty, a single slash, or two slashes. The tail
+        contains anything after the root. For example:
+
+            splitroot('foo/bar') == ('', '', 'foo/bar')
+            splitroot('/foo/bar') == ('', '/', 'foo/bar')
+            splitroot('//foo/bar') == ('', '//', 'foo/bar')
+            splitroot('///foo/bar') == ('', '/', '//foo/bar')
+        """
+        p = os.fspath(p)
+        if isinstance(p, bytes):
+            # Optimisation: the drive is always empty
+            _, root, tail = _path_splitroot_ex(os.fsdecode(p))
+            return b'', os.fsencode(root), os.fsencode(tail)
+        return _path_splitroot_ex(p)
 
 
 # Return the tail (basename) part of a path, same as split(path)[1].
diff --git a/Lib/sqlite3/dump.py b/Lib/sqlite3/dump.py
index 9dcce7dc76ced48..57e6a3b4f1e6eba 100644
--- a/Lib/sqlite3/dump.py
+++ b/Lib/sqlite3/dump.py
@@ -26,6 +26,7 @@ def _iterdump(connection, *, filter=None):
 
     writeable_schema = False
     cu = connection.cursor()
+    cu.row_factory = None  # Make sure we get predictable results.
     # Disable foreign key constraints, if there is any foreign key violation.
     violations = cu.execute("PRAGMA foreign_key_check").fetchall()
     if violations:
diff --git a/Lib/test/test_capi/test_mem.py b/Lib/test/test_capi/test_mem.py
index 296601e8ee4f5f7..6ab7b685c2e18bd 100644
--- a/Lib/test/test_capi/test_mem.py
+++ b/Lib/test/test_capi/test_mem.py
@@ -153,7 +153,7 @@ class C(): pass
 
 
 # free-threading requires mimalloc (not malloc)
-@support.requires_gil_enabled
+@support.requires_gil_enabled()
 class PyMemMallocDebugTests(PyMemDebugTests):
     PYTHONMALLOC = 'malloc_debug'
 
diff --git a/Lib/test/test_capi/test_opt.py b/Lib/test/test_capi/test_opt.py
index c004f4637700190..e2e772a52d764e5 100644
--- a/Lib/test/test_capi/test_opt.py
+++ b/Lib/test/test_capi/test_opt.py
@@ -1286,5 +1286,17 @@ def testfunc(n):
         self.assertEqual(res, 32 * 32)
         self.assertIsNone(ex)
 
+    def test_return_generator(self):
+        def gen():
+            yield None
+        def testfunc(n):
+            for i in range(n):
+                gen()
+            return i
+        res, ex = self._run_with_optimizer(testfunc, 20)
+        self.assertEqual(res, 19)
+        self.assertIsNotNone(ex)
+        self.assertIn("_RETURN_GENERATOR", get_opnames(ex))
+
 if __name__ == "__main__":
     unittest.main()
diff --git a/Lib/test/test_gdb/test_backtrace.py b/Lib/test/test_gdb/test_backtrace.py
index fe67bf9ecc88803..714853c7b4732d9 100644
--- a/Lib/test/test_gdb/test_backtrace.py
+++ b/Lib/test/test_gdb/test_backtrace.py
@@ -49,7 +49,7 @@ def test_bt_full(self):
 
     @unittest.skipIf(python_is_optimized(),
                      "Python was compiled with optimizations")
-    @support.requires_gil_enabled
+    @support.requires_gil_enabled()
     @support.requires_resource('cpu')
     def test_threads(self):
         'Verify that "py-bt" indicates threads that are waiting for the GIL'
diff --git a/Lib/test/test_ipaddress.py b/Lib/test/test_ipaddress.py
index f1519df673747a9..c3ecf2a742941a6 100644
--- a/Lib/test/test_ipaddress.py
+++ b/Lib/test/test_ipaddress.py
@@ -2446,6 +2446,22 @@ def testIpv4MappedPrivateCheck(self):
         self.assertEqual(
                 False, ipaddress.ip_address('::ffff:172.32.0.0').is_private)
 
+    def testIpv4MappedLoopbackCheck(self):
+        # test networks
+        self.assertEqual(True, ipaddress.ip_network(
+                '::ffff:127.100.200.254/128').is_loopback)
+        self.assertEqual(True, ipaddress.ip_network(
+                '::ffff:127.42.0.0/112').is_loopback)
+        self.assertEqual(False, ipaddress.ip_network(
+                '::ffff:128.0.0.0').is_loopback)
+        # test addresses
+        self.assertEqual(True, ipaddress.ip_address(
+                '::ffff:127.100.200.254').is_loopback)
+        self.assertEqual(True, ipaddress.ip_address(
+                '::ffff:127.42.0.0').is_loopback)
+        self.assertEqual(False, ipaddress.ip_address(
+                '::ffff:128.0.0.0').is_loopback)
+
     def testAddrExclude(self):
         addr1 = ipaddress.ip_network('10.1.1.0/24')
         addr2 = ipaddress.ip_network('10.1.1.0/26')
diff --git a/Lib/test/test_ntpath.py b/Lib/test/test_ntpath.py
index 31156130fcc7474..7f91bf1c2b837a4 100644
--- a/Lib/test/test_ntpath.py
+++ b/Lib/test/test_ntpath.py
@@ -374,6 +374,7 @@ def test_normpath(self):
         tester("ntpath.normpath('\\\\foo\\')", '\\\\foo\\')
         tester("ntpath.normpath('\\\\foo')", '\\\\foo')
         tester("ntpath.normpath('\\\\')", '\\\\')
+        tester("ntpath.normpath('//?/UNC/server/share/..')", '\\\\?\\UNC\\server\\share\\')
 
     def test_realpath_curdir(self):
         expected = ntpath.normpath(os.getcwd())
diff --git a/Lib/test/test_sqlite3/test_dump.py b/Lib/test/test_sqlite3/test_dump.py
index 7261b7f0dc93d0a..d508f238f84fb5d 100644
--- a/Lib/test/test_sqlite3/test_dump.py
+++ b/Lib/test/test_sqlite3/test_dump.py
@@ -190,6 +190,21 @@ def __getitem__(self, index):
         got = list(self.cx.iterdump())
         self.assertEqual(expected, got)
 
+    def test_dump_custom_row_factory(self):
+        # gh-118221: iterdump should be able to cope with custom row factories.
+        def dict_factory(cu, row):
+            fields = [col[0] for col in cu.description]
+            return dict(zip(fields, row))
+
+        self.cx.row_factory = dict_factory
+        CREATE_TABLE = "CREATE TABLE test(t);"
+        expected = ["BEGIN TRANSACTION;", CREATE_TABLE, "COMMIT;"]
+
+        self.cu.execute(CREATE_TABLE)
+        actual = list(self.cx.iterdump())
+        self.assertEqual(expected, actual)
+        self.assertEqual(self.cx.row_factory, dict_factory)
+
     def test_dump_virtual_tables(self):
         # gh-64662
         expected = [
diff --git a/Misc/NEWS.d/next/Core and Builtins/2024-04-19-08-50-48.gh-issue-102511.qDEB66.rst b/Misc/NEWS.d/next/Core and Builtins/2024-04-19-08-50-48.gh-issue-102511.qDEB66.rst
new file mode 100644
index 000000000000000..dfdf250710778e5
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2024-04-19-08-50-48.gh-issue-102511.qDEB66.rst	
@@ -0,0 +1 @@
+Speed up :func:`os.path.splitroot` with a native implementation.
diff --git a/Misc/NEWS.d/next/Library/2024-04-05-15-51-01.gh-issue-117566.54nABf.rst b/Misc/NEWS.d/next/Library/2024-04-05-15-51-01.gh-issue-117566.54nABf.rst
new file mode 100644
index 000000000000000..56c2fb0e25d494c
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-04-05-15-51-01.gh-issue-117566.54nABf.rst
@@ -0,0 +1,3 @@
+:meth:`ipaddress.IPv6Address.is_loopback` will now return ``True`` for
+IPv4-mapped loopback addresses, i.e. addresses in the
+``::ffff:127.0.0.0/104`` address space.
diff --git a/Misc/NEWS.d/next/Library/2024-04-24-12-29-33.gh-issue-118221.2k_bac.rst b/Misc/NEWS.d/next/Library/2024-04-24-12-29-33.gh-issue-118221.2k_bac.rst
new file mode 100644
index 000000000000000..9b0ea9978a195eb
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-04-24-12-29-33.gh-issue-118221.2k_bac.rst
@@ -0,0 +1,2 @@
+Fix a bug where :func:`sqlite3.iterdump` could fail if a custom :attr:`row
+factory <sqlite3.Connection.row_factory>` was used. Patch by Erlend Aasland.
diff --git a/Modules/_decimal/_decimal.c b/Modules/_decimal/_decimal.c
index 2481455ac0d1437..fa425f4f740d312 100644
--- a/Modules/_decimal/_decimal.c
+++ b/Modules/_decimal/_decimal.c
@@ -32,6 +32,7 @@
 #include <Python.h>
 #include "pycore_long.h"          // _PyLong_IsZero()
 #include "pycore_pystate.h"       // _PyThreadState_GET()
+#include "pycore_typeobject.h"
 #include "complexobject.h"
 #include "mpdecimal.h"
 
@@ -120,11 +121,8 @@ get_module_state_by_def(PyTypeObject *tp)
 static inline decimal_state *
 find_state_left_or_right(PyObject *left, PyObject *right)
 {
-    PyObject *mod = PyType_GetModuleByDef(Py_TYPE(left), &_decimal_module);
-    if (mod == NULL) {
-        PyErr_Clear();
-        mod = PyType_GetModuleByDef(Py_TYPE(right), &_decimal_module);
-    }
+    PyObject *mod = _PyType_GetModuleByDef2(Py_TYPE(left), Py_TYPE(right),
+                                            &_decimal_module);
     assert(mod != NULL);
     return get_module_state(mod);
 }
diff --git a/Modules/_testcapi/run.c b/Modules/_testcapi/run.c
index fa3251c4b5b3100..4fd98b82d762ff4 100644
--- a/Modules/_testcapi/run.c
+++ b/Modules/_testcapi/run.c
@@ -74,8 +74,10 @@ run_fileexflags(PyObject *mod, PyObject *pos_args)
 
     result = PyRun_FileExFlags(fp, filename, start, globals, locals, closeit, pflags);
 
-#if !defined(__wasi__)
-    /* The behavior of fileno() after fclose() is undefined. */
+#if defined(__linux__) || defined(MS_WINDOWS) || defined(__APPLE__)
+    /* The behavior of fileno() after fclose() is undefined, but it is
+     * the only practical way to check whether the file was closed.
+     * Only test this on the known platforms. */
     if (closeit && result && fileno(fp) >= 0) {
         PyErr_SetString(PyExc_AssertionError, "File was not closed after excution");
         Py_DECREF(result);
diff --git a/Modules/clinic/posixmodule.c.h b/Modules/clinic/posixmodule.c.h
index 0398629e3c10ce9..a0d1f3238a6733b 100644
--- a/Modules/clinic/posixmodule.c.h
+++ b/Modules/clinic/posixmodule.c.h
@@ -2248,6 +2248,64 @@ os__path_islink(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObj
 
 #endif /* defined(MS_WINDOWS) */
 
+PyDoc_STRVAR(os__path_splitroot_ex__doc__,
+"_path_splitroot_ex($module, /, path)\n"
+"--\n"
+"\n");
+
+#define OS__PATH_SPLITROOT_EX_METHODDEF    \
+    {"_path_splitroot_ex", _PyCFunction_CAST(os__path_splitroot_ex), METH_FASTCALL|METH_KEYWORDS, os__path_splitroot_ex__doc__},
+
+static PyObject *
+os__path_splitroot_ex_impl(PyObject *module, PyObject *path);
+
+static PyObject *
+os__path_splitroot_ex(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 1
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(path), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"path", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "_path_splitroot_ex",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[1];
+    PyObject *path;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    if (!PyUnicode_Check(args[0])) {
+        _PyArg_BadArgument("_path_splitroot_ex", "argument 'path'", "str", args[0]);
+        goto exit;
+    }
+    path = args[0];
+    return_value = os__path_splitroot_ex_impl(module, path);
+
+exit:
+    return return_value;
+}
+
 PyDoc_STRVAR(os__path_normpath__doc__,
 "_path_normpath($module, /, path)\n"
 "--\n"
@@ -12602,4 +12660,4 @@ os__supports_virtual_terminal(PyObject *module, PyObject *Py_UNUSED(ignored))
 #ifndef OS__SUPPORTS_VIRTUAL_TERMINAL_METHODDEF
     #define OS__SUPPORTS_VIRTUAL_TERMINAL_METHODDEF
 #endif /* !defined(OS__SUPPORTS_VIRTUAL_TERMINAL_METHODDEF) */
-/*[clinic end generated code: output=511f0788a6b90db0 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=c4698b47007cd6eb input=a9049054013a1b77]*/
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 5e54cf64cd563ec..c9d67ccbb8c9089 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -5467,6 +5467,49 @@ os__path_islink_impl(PyObject *module, PyObject *path)
 #endif /* MS_WINDOWS */
 
 
+/*[clinic input]
+os._path_splitroot_ex
+
+    path: unicode
+
+[clinic start generated code]*/
+
+static PyObject *
+os__path_splitroot_ex_impl(PyObject *module, PyObject *path)
+/*[clinic end generated code: output=de97403d3dfebc40 input=f1470e12d899f9ac]*/
+{
+    Py_ssize_t len, drvsize, rootsize;
+    PyObject *drv = NULL, *root = NULL, *tail = NULL, *result = NULL;
+
+    wchar_t *buffer = PyUnicode_AsWideCharString(path, &len);
+    if (!buffer) {
+        goto exit;
+    }
+
+    _Py_skiproot(buffer, len, &drvsize, &rootsize);
+    drv = PyUnicode_FromWideChar(buffer, drvsize);
+    if (drv == NULL) {
+        goto exit;
+    }
+    root = PyUnicode_FromWideChar(&buffer[drvsize], rootsize);
+    if (root == NULL) {
+        goto exit;
+    }
+    tail = PyUnicode_FromWideChar(&buffer[drvsize + rootsize],
+                                  len - drvsize - rootsize);
+    if (tail == NULL) {
+        goto exit;
+    }
+    result = Py_BuildValue("(OOO)", drv, root, tail);
+exit:
+    PyMem_Free(buffer);
+    Py_XDECREF(drv);
+    Py_XDECREF(root);
+    Py_XDECREF(tail);
+    return result;
+}
+
+
 /*[clinic input]
 os._path_normpath
 
@@ -16799,6 +16842,7 @@ static PyMethodDef posix_methods[] = {
     OS__FINDFIRSTFILE_METHODDEF
     OS__GETVOLUMEPATHNAME_METHODDEF
     OS__PATH_SPLITROOT_METHODDEF
+    OS__PATH_SPLITROOT_EX_METHODDEF
     OS__PATH_NORMPATH_METHODDEF
     OS_GETLOADAVG_METHODDEF
     OS_URANDOM_METHODDEF
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 2644516bc307706..afcf535f8c0a78a 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -1097,10 +1097,11 @@ compare_unicode_unicode(PyDictObject *mp, PyDictKeysObject *dk,
                         void *ep0, Py_ssize_t ix, PyObject *key, Py_hash_t hash)
 {
     PyDictUnicodeEntry *ep = &((PyDictUnicodeEntry *)ep0)[ix];
-    assert(ep->me_key != NULL);
-    assert(PyUnicode_CheckExact(ep->me_key));
-    if (ep->me_key == key ||
-            (unicode_get_hash(ep->me_key) == hash && unicode_eq(ep->me_key, key))) {
+    PyObject *ep_key = FT_ATOMIC_LOAD_PTR_RELAXED(ep->me_key);
+    assert(ep_key != NULL);
+    assert(PyUnicode_CheckExact(ep_key));
+    if (ep_key == key ||
+            (unicode_get_hash(ep_key) == hash && unicode_eq(ep_key, key))) {
         return 1;
     }
     return 0;
@@ -1761,10 +1762,12 @@ insertdict(PyInterpreterState *interp, PyDictObject *mp,
         else {
             assert(old_value != NULL);
             if (DK_IS_UNICODE(mp->ma_keys)) {
-                DK_UNICODE_ENTRIES(mp->ma_keys)[ix].me_value = value;
+                PyDictUnicodeEntry *ep = &DK_UNICODE_ENTRIES(mp->ma_keys)[ix];
+                STORE_VALUE(ep, value);
             }
             else {
-                DK_ENTRIES(mp->ma_keys)[ix].me_value = value;
+                PyDictKeyEntry *ep = &DK_ENTRIES(mp->ma_keys)[ix];
+                STORE_VALUE(ep, value);
             }
         }
         mp->ma_version_tag = new_version;
@@ -1810,15 +1813,15 @@ insert_to_emptydict(PyInterpreterState *interp, PyDictObject *mp,
     if (unicode) {
         PyDictUnicodeEntry *ep = DK_UNICODE_ENTRIES(newkeys);
         ep->me_key = key;
-        ep->me_value = value;
+        STORE_VALUE(ep, value);
     }
     else {
         PyDictKeyEntry *ep = DK_ENTRIES(newkeys);
         ep->me_key = key;
         ep->me_hash = hash;
-        ep->me_value = value;
+        STORE_VALUE(ep, value);
     }
-    mp->ma_used++;
+    FT_ATOMIC_STORE_SSIZE_RELAXED(mp->ma_used, FT_ATOMIC_LOAD_SSIZE_RELAXED(mp->ma_used) + 1);
     mp->ma_version_tag = new_version;
     newkeys->dk_usable--;
     newkeys->dk_nentries++;
@@ -2510,7 +2513,7 @@ delitem_common(PyDictObject *mp, Py_hash_t hash, Py_ssize_t ix,
     Py_ssize_t hashpos = lookdict_index(mp->ma_keys, hash, ix);
     assert(hashpos >= 0);
 
-    mp->ma_used--;
+    FT_ATOMIC_STORE_SSIZE_RELAXED(mp->ma_used, FT_ATOMIC_LOAD_SSIZE(mp->ma_used) - 1);
     mp->ma_version_tag = new_version;
     if (_PyDict_HasSplitTable(mp)) {
         assert(old_value == mp->ma_values->values[ix]);
@@ -6895,7 +6898,7 @@ _PyObject_TryGetInstanceAttribute(PyObject *obj, PyObject *name, PyObject **attr
     }
 
 #ifdef Py_GIL_DISABLED
-    PyObject *value = _Py_atomic_load_ptr_relaxed(&values->values[ix]);
+    PyObject *value = _Py_atomic_load_ptr_acquire(&values->values[ix]);
     if (value == NULL || _Py_TryIncrefCompare(&values->values[ix], value)) {
         *attr = value;
         return true;
diff --git a/Objects/frameobject.c b/Objects/frameobject.c
index d55c246d80dd6a7..07b7ef3df46a5c2 100644
--- a/Objects/frameobject.c
+++ b/Objects/frameobject.c
@@ -304,11 +304,6 @@ mark_stacks(PyCodeObject *code_obj, int len)
         stacks[i] = UNINITIALIZED;
     }
     stacks[0] = EMPTY_STACK;
-    if (code_obj->co_flags & (CO_GENERATOR | CO_COROUTINE | CO_ASYNC_GENERATOR))
-    {
-        // Generators get sent None while starting:
-        stacks[0] = push_value(stacks[0], Object);
-    }
     int todo = 1;
     while (todo) {
         todo = 0;
diff --git a/Objects/setobject.c b/Objects/setobject.c
index 0d88f4ff922d249..19975e3d4d18e25 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -2333,6 +2333,13 @@ set_init(PySetObject *self, PyObject *args, PyObject *kwds)
     if (!PyArg_UnpackTuple(args, Py_TYPE(self)->tp_name, 0, 1, &iterable))
         return -1;
 
+    if (Py_REFCNT(self) == 1 && self->fill == 0) {
+        self->hash = -1;
+        if (iterable == NULL) {
+            return 0;
+        }
+        return set_update_local(self, iterable);
+    }
     Py_BEGIN_CRITICAL_SECTION(self);
     if (self->fill)
         set_clear_internal(self);
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 808e11fcbaf1ff9..07e0a5a02da87ff 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -4825,11 +4825,24 @@ PyType_GetModuleState(PyTypeObject *type)
 /* Get the module of the first superclass where the module has the
  * given PyModuleDef.
  */
-PyObject *
-PyType_GetModuleByDef(PyTypeObject *type, PyModuleDef *def)
+static inline PyObject *
+get_module_by_def(PyTypeObject *type, PyModuleDef *def)
 {
     assert(PyType_Check(type));
 
+    if (!_PyType_HasFeature(type, Py_TPFLAGS_HEAPTYPE)) {
+        // type_ready_mro() ensures that no heap type is
+        // contained in a static type MRO.
+        return NULL;
+    }
+    else {
+        PyHeapTypeObject *ht = (PyHeapTypeObject*)type;
+        PyObject *module = ht->ht_module;
+        if (module && _PyModule_GetDef(module) == def) {
+            return module;
+        }
+    }
+
     PyObject *res = NULL;
     BEGIN_TYPE_LOCK()
 
@@ -4837,12 +4850,14 @@ PyType_GetModuleByDef(PyTypeObject *type, PyModuleDef *def)
     // The type must be ready
     assert(mro != NULL);
     assert(PyTuple_Check(mro));
-    // mro_invoke() ensures that the type MRO cannot be empty, so we don't have
-    // to check i < PyTuple_GET_SIZE(mro) at the first loop iteration.
+    // mro_invoke() ensures that the type MRO cannot be empty.
     assert(PyTuple_GET_SIZE(mro) >= 1);
+    // Also, the first item in the MRO is the type itself, which
+    // we already checked above. We skip it in the loop.
+    assert(PyTuple_GET_ITEM(mro, 0) == (PyObject *)type);
 
     Py_ssize_t n = PyTuple_GET_SIZE(mro);
-    for (Py_ssize_t i = 0; i < n; i++) {
+    for (Py_ssize_t i = 1; i < n; i++) {
         PyObject *super = PyTuple_GET_ITEM(mro, i);
         if(!_PyType_HasFeature((PyTypeObject *)super, Py_TPFLAGS_HEAPTYPE)) {
             // Static types in the MRO need to be skipped
@@ -4857,14 +4872,37 @@ PyType_GetModuleByDef(PyTypeObject *type, PyModuleDef *def)
         }
     }
     END_TYPE_LOCK()
+    return res;
+}
 
-    if (res == NULL) {
+PyObject *
+PyType_GetModuleByDef(PyTypeObject *type, PyModuleDef *def)
+{
+    PyObject *module = get_module_by_def(type, def);
+    if (module == NULL) {
         PyErr_Format(
             PyExc_TypeError,
             "PyType_GetModuleByDef: No superclass of '%s' has the given module",
             type->tp_name);
     }
-    return res;
+    return module;
+}
+
+PyObject *
+_PyType_GetModuleByDef2(PyTypeObject *left, PyTypeObject *right,
+                        PyModuleDef *def)
+{
+    PyObject *module = get_module_by_def(left, def);
+    if (module == NULL) {
+        module = get_module_by_def(right, def);
+        if (module == NULL) {
+            PyErr_Format(
+                PyExc_TypeError,
+                "PyType_GetModuleByDef: No superclass of '%s' nor '%s' has "
+                "the given module", left->tp_name, right->tp_name);
+        }
+    }
+    return module;
 }
 
 void *
diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index c31617d35b02f5c..485504914912f91 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -837,12 +837,7 @@ dummy_func(
             _PyFrame_StackPush(frame, retval);
             LOAD_SP();
             LOAD_IP(frame->return_offset);
-#if LLTRACE && TIER_ONE
-            lltrace = maybe_lltrace_resume_frame(frame, &entry_frame, GLOBALS());
-            if (lltrace < 0) {
-                goto exit_unwind;
-            }
-#endif
+            LLTRACE_RESUME_FRAME();
         }
 
         macro(RETURN_VALUE) =
@@ -3186,12 +3181,7 @@ dummy_func(
             tstate->py_recursion_remaining--;
             LOAD_SP();
             LOAD_IP(0);
-#if LLTRACE && TIER_ONE
-            lltrace = maybe_lltrace_resume_frame(frame, &entry_frame, GLOBALS());
-            if (lltrace < 0) {
-                goto exit_unwind;
-            }
-#endif
+            LLTRACE_RESUME_FRAME();
         }
 
         macro(CALL_BOUND_METHOD_EXACT_ARGS) =
@@ -3877,7 +3867,7 @@ dummy_func(
             }
         }
 
-        tier1 inst(RETURN_GENERATOR, (--)) {
+        inst(RETURN_GENERATOR, (-- res)) {
             assert(PyFunction_Check(frame->f_funcobj));
             PyFunctionObject *func = (PyFunctionObject *)frame->f_funcobj;
             PyGenObject *gen = (PyGenObject *)_Py_MakeCoro(func);
@@ -3887,19 +3877,19 @@ dummy_func(
             assert(EMPTY());
             _PyFrame_SetStackPointer(frame, stack_pointer);
             _PyInterpreterFrame *gen_frame = (_PyInterpreterFrame *)gen->gi_iframe;
-            frame->instr_ptr = next_instr;
+            frame->instr_ptr++;
             _PyFrame_Copy(frame, gen_frame);
             assert(frame->frame_obj == NULL);
             gen->gi_frame_state = FRAME_CREATED;
             gen_frame->owner = FRAME_OWNED_BY_GENERATOR;
             _Py_LeaveRecursiveCallPy(tstate);
-            assert(frame != &entry_frame);
+            res = (PyObject *)gen;
             _PyInterpreterFrame *prev = frame->previous;
             _PyThreadState_PopFrame(tstate, frame);
             frame = tstate->current_frame = prev;
-            _PyFrame_StackPush(frame, (PyObject *)gen);
             LOAD_IP(frame->return_offset);
-            goto resume_frame;
+            LOAD_SP();
+            LLTRACE_RESUME_FRAME();
         }
 
         inst(BUILD_SLICE, (start, stop, step if (oparg == 3) -- slice)) {
diff --git a/Python/ceval_macros.h b/Python/ceval_macros.h
index 224cd1da7d4a0e9..871d1747e2bb8d2 100644
--- a/Python/ceval_macros.h
+++ b/Python/ceval_macros.h
@@ -86,6 +86,18 @@
 #define PRE_DISPATCH_GOTO() ((void)0)
 #endif
 
+#if LLTRACE
+#define LLTRACE_RESUME_FRAME() \
+do { \
+    lltrace = maybe_lltrace_resume_frame(frame, &entry_frame, GLOBALS()); \
+    if (lltrace < 0) { \
+        goto exit_unwind; \
+    } \
+} while (0)
+#else
+#define LLTRACE_RESUME_FRAME() ((void)0)
+#endif
+
 #ifdef Py_GIL_DISABLED
 #define QSBR_QUIESCENT_STATE(tstate) _Py_qsbr_quiescent_state(((_PyThreadStateImpl *)tstate)->qsbr)
 #else
diff --git a/Python/executor_cases.c.h b/Python/executor_cases.c.h
index 7403d6fdaf0e2b2..1eb3da9b70002c4 100644
--- a/Python/executor_cases.c.h
+++ b/Python/executor_cases.c.h
@@ -988,12 +988,7 @@
             _PyFrame_StackPush(frame, retval);
             LOAD_SP();
             LOAD_IP(frame->return_offset);
-            #if LLTRACE && TIER_ONE
-            lltrace = maybe_lltrace_resume_frame(frame, &entry_frame, GLOBALS());
-            if (lltrace < 0) {
-                goto exit_unwind;
-            }
-            #endif
+            LLTRACE_RESUME_FRAME();
             break;
         }
 
@@ -3213,12 +3208,7 @@
             tstate->py_recursion_remaining--;
             LOAD_SP();
             LOAD_IP(0);
-            #if LLTRACE && TIER_ONE
-            lltrace = maybe_lltrace_resume_frame(frame, &entry_frame, GLOBALS());
-            if (lltrace < 0) {
-                goto exit_unwind;
-            }
-            #endif
+            LLTRACE_RESUME_FRAME();
             break;
         }
 
@@ -3833,6 +3823,35 @@
             break;
         }
 
+        case _RETURN_GENERATOR: {
+            PyObject *res;
+            assert(PyFunction_Check(frame->f_funcobj));
+            PyFunctionObject *func = (PyFunctionObject *)frame->f_funcobj;
+            PyGenObject *gen = (PyGenObject *)_Py_MakeCoro(func);
+            if (gen == NULL) {
+                JUMP_TO_ERROR();
+            }
+            assert(EMPTY());
+            _PyFrame_SetStackPointer(frame, stack_pointer);
+            _PyInterpreterFrame *gen_frame = (_PyInterpreterFrame *)gen->gi_iframe;
+            frame->instr_ptr++;
+            _PyFrame_Copy(frame, gen_frame);
+            assert(frame->frame_obj == NULL);
+            gen->gi_frame_state = FRAME_CREATED;
+            gen_frame->owner = FRAME_OWNED_BY_GENERATOR;
+            _Py_LeaveRecursiveCallPy(tstate);
+            res = (PyObject *)gen;
+            _PyInterpreterFrame *prev = frame->previous;
+            _PyThreadState_PopFrame(tstate, frame);
+            frame = tstate->current_frame = prev;
+            LOAD_IP(frame->return_offset);
+            LOAD_SP();
+            LLTRACE_RESUME_FRAME();
+            stack_pointer[0] = res;
+            stack_pointer += 1;
+            break;
+        }
+
         case _BUILD_SLICE: {
             PyObject *step = NULL;
             PyObject *stop;
diff --git a/Python/fileutils.c b/Python/fileutils.c
index 882d3299575cf3b..54853ba2f75d9d0 100644
--- a/Python/fileutils.c
+++ b/Python/fileutils.c
@@ -2295,6 +2295,99 @@ PathCchCombineEx(wchar_t *buffer, size_t bufsize, const wchar_t *dirname,
 
 #endif /* defined(MS_WINDOWS_GAMES) && !defined(MS_WINDOWS_DESKTOP) */
 
+void
+_Py_skiproot(const wchar_t *path, Py_ssize_t size, Py_ssize_t *drvsize,
+             Py_ssize_t *rootsize)
+{
+    assert(drvsize);
+    assert(rootsize);
+#ifndef MS_WINDOWS
+#define IS_SEP(x) (*(x) == SEP)
+    *drvsize = 0;
+    if (!IS_SEP(&path[0])) {
+        // Relative path, e.g.: 'foo'
+        *rootsize = 0;
+    }
+    else if (!IS_SEP(&path[1]) || IS_SEP(&path[2])) {
+        // Absolute path, e.g.: '/foo', '///foo', '////foo', etc.
+        *rootsize = 1;
+    }
+    else {
+        // Precisely two leading slashes, e.g.: '//foo'. Implementation defined per POSIX, see
+        // https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13
+        *rootsize = 2;
+    }
+#undef IS_SEP
+#else
+    const wchar_t *pEnd = size >= 0 ? &path[size] : NULL;
+#define IS_END(x) (pEnd ? (x) == pEnd : !*(x))
+#define IS_SEP(x) (*(x) == SEP || *(x) == ALTSEP)
+#define SEP_OR_END(x) (IS_SEP(x) || IS_END(x))
+    if (IS_SEP(&path[0])) {
+        if (IS_SEP(&path[1])) {
+            // Device drives, e.g. \\.\device or \\?\device
+            // UNC drives, e.g. \\server\share or \\?\UNC\server\share
+            Py_ssize_t idx;
+            if (path[2] == L'?' && IS_SEP(&path[3]) &&
+                (path[4] == L'U' || path[4] == L'u') &&
+                (path[5] == L'N' || path[5] == L'n') &&
+                (path[6] == L'C' || path[6] == L'c') &&
+                IS_SEP(&path[7]))
+            {
+                idx = 8;
+            }
+            else {
+                idx = 2;
+            }
+            while (!SEP_OR_END(&path[idx])) {
+                idx++;
+            }
+            if (IS_END(&path[idx])) {
+                *drvsize = idx;
+                *rootsize = 0;
+            }
+            else {
+                idx++;
+                while (!SEP_OR_END(&path[idx])) {
+                    idx++;
+                }
+                *drvsize = idx;
+                if (IS_END(&path[idx])) {
+                    *rootsize = 0;
+                }
+                else {
+                    *rootsize = 1;
+                }
+            }
+        }
+        else {
+            // Relative path with root, e.g. \Windows
+            *drvsize = 0;
+            *rootsize = 1;
+        }
+    }
+    else if (!IS_END(&path[0]) && path[1] == L':') {
+        *drvsize = 2;
+        if (IS_SEP(&path[2])) {
+            // Absolute drive-letter path, e.g. X:\Windows
+            *rootsize = 1;
+        }
+        else {
+            // Relative path with drive, e.g. X:Windows
+            *rootsize = 0;
+        }
+    }
+    else {
+        // Relative path, e.g. Windows
+        *drvsize = 0;
+        *rootsize = 0;
+    }
+#undef SEP_OR_END
+#undef IS_SEP
+#undef IS_END
+#endif
+}
+
 // The caller must ensure "buffer" is big enough.
 static int
 join_relfile(wchar_t *buffer, size_t bufsize,
@@ -2411,49 +2504,39 @@ _Py_normpath_and_size(wchar_t *path, Py_ssize_t size, Py_ssize_t *normsize)
 #endif
 #define SEP_OR_END(x) (IS_SEP(x) || IS_END(x))
 
-    // Skip leading '.\'
     if (p1[0] == L'.' && IS_SEP(&p1[1])) {
+        // Skip leading '.\'
         path = &path[2];
-        while (IS_SEP(path) && !IS_END(path)) {
+        while (IS_SEP(path)) {
             path++;
         }
         p1 = p2 = minP2 = path;
         lastC = SEP;
     }
+    else {
+        Py_ssize_t drvsize, rootsize;
+        _Py_skiproot(path, size, &drvsize, &rootsize);
+        if (drvsize || rootsize) {
+            // Skip past root and update minP2
+            p1 = &path[drvsize + rootsize];
+#ifndef ALTSEP
+            p2 = p1;
+#else
+            for (; p2 < p1; ++p2) {
+                if (*p2 == ALTSEP) {
+                    *p2 = SEP;
+                }
+            }
+#endif
+            minP2 = p2 - 1;
+            lastC = *minP2;
 #ifdef MS_WINDOWS
-    // Skip past drive segment and update minP2
-    else if (p1[0] && p1[1] == L':') {
-        *p2++ = *p1++;
-        *p2++ = *p1++;
-        minP2 = p2;
-        lastC = L':';
-    }
-    // Skip past all \\-prefixed paths, including \\?\, \\.\,
-    // and network paths, including the first segment.
-    else if (IS_SEP(&p1[0]) && IS_SEP(&p1[1])) {
-        int sepCount = 2;
-        *p2++ = SEP;
-        *p2++ = SEP;
-        p1 += 2;
-        for (; !IS_END(p1) && sepCount; ++p1) {
-            if (IS_SEP(p1)) {
-                --sepCount;
-                *p2++ = lastC = SEP;
-            } else {
-                *p2++ = lastC = *p1;
+            if (lastC != SEP) {
+                minP2++;
             }
+#endif
         }
-        minP2 = p2 - 1;
-    }
-#else
-    // Skip past two leading SEPs
-    else if (IS_SEP(&p1[0]) && IS_SEP(&p1[1]) && !IS_SEP(&p1[2])) {
-        *p2++ = *p1++;
-        *p2++ = *p1++;
-        minP2 = p2 - 1;  // Absolute path has SEP at minP2
-        lastC = SEP;
     }
-#endif /* MS_WINDOWS */
 
     /* if pEnd is specified, check that. Else, check for null terminator */
     for (; !IS_END(p1); ++p1) {
diff --git a/Python/frame.c b/Python/frame.c
index f88a8f0d73d3f87..db9d13359a23ca2 100644
--- a/Python/frame.c
+++ b/Python/frame.c
@@ -53,18 +53,6 @@ _PyFrame_MakeAndSetFrameObject(_PyInterpreterFrame *frame)
     return f;
 }
 
-void
-_PyFrame_Copy(_PyInterpreterFrame *src, _PyInterpreterFrame *dest)
-{
-    assert(src->stacktop >= _PyFrame_GetCode(src)->co_nlocalsplus);
-    Py_ssize_t size = ((char*)&src->localsplus[src->stacktop]) - (char *)src;
-    memcpy(dest, src, size);
-    // Don't leave a dangling pointer to the old frame when creating generators
-    // and coroutines:
-    dest->previous = NULL;
-}
-
-
 static void
 take_ownership(PyFrameObject *f, _PyInterpreterFrame *frame)
 {
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index 058cac8bedd9179..0c58f3f87d40412 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -997,12 +997,7 @@
                 tstate->py_recursion_remaining--;
                 LOAD_SP();
                 LOAD_IP(0);
-                #if LLTRACE && TIER_ONE
-                lltrace = maybe_lltrace_resume_frame(frame, &entry_frame, GLOBALS());
-                if (lltrace < 0) {
-                    goto exit_unwind;
-                }
-                #endif
+                LLTRACE_RESUME_FRAME();
             }
             DISPATCH();
         }
@@ -1786,12 +1781,7 @@
                 tstate->py_recursion_remaining--;
                 LOAD_SP();
                 LOAD_IP(0);
-                #if LLTRACE && TIER_ONE
-                lltrace = maybe_lltrace_resume_frame(frame, &entry_frame, GLOBALS());
-                if (lltrace < 0) {
-                    goto exit_unwind;
-                }
-                #endif
+                LLTRACE_RESUME_FRAME();
             }
             DISPATCH();
         }
@@ -4992,12 +4982,7 @@
                 _PyFrame_StackPush(frame, retval);
                 LOAD_SP();
                 LOAD_IP(frame->return_offset);
-                #if LLTRACE && TIER_ONE
-                lltrace = maybe_lltrace_resume_frame(frame, &entry_frame, GLOBALS());
-                if (lltrace < 0) {
-                    goto exit_unwind;
-                }
-                #endif
+                LLTRACE_RESUME_FRAME();
             }
             DISPATCH();
         }
@@ -5006,6 +4991,7 @@
             frame->instr_ptr = next_instr;
             next_instr += 1;
             INSTRUCTION_STATS(RETURN_GENERATOR);
+            PyObject *res;
             assert(PyFunction_Check(frame->f_funcobj));
             PyFunctionObject *func = (PyFunctionObject *)frame->f_funcobj;
             PyGenObject *gen = (PyGenObject *)_Py_MakeCoro(func);
@@ -5015,19 +5001,22 @@
             assert(EMPTY());
             _PyFrame_SetStackPointer(frame, stack_pointer);
             _PyInterpreterFrame *gen_frame = (_PyInterpreterFrame *)gen->gi_iframe;
-            frame->instr_ptr = next_instr;
+            frame->instr_ptr++;
             _PyFrame_Copy(frame, gen_frame);
             assert(frame->frame_obj == NULL);
             gen->gi_frame_state = FRAME_CREATED;
             gen_frame->owner = FRAME_OWNED_BY_GENERATOR;
             _Py_LeaveRecursiveCallPy(tstate);
-            assert(frame != &entry_frame);
+            res = (PyObject *)gen;
             _PyInterpreterFrame *prev = frame->previous;
             _PyThreadState_PopFrame(tstate, frame);
             frame = tstate->current_frame = prev;
-            _PyFrame_StackPush(frame, (PyObject *)gen);
             LOAD_IP(frame->return_offset);
-            goto resume_frame;
+            LOAD_SP();
+            LLTRACE_RESUME_FRAME();
+            stack_pointer[0] = res;
+            stack_pointer += 1;
+            DISPATCH();
         }
 
         TARGET(RETURN_VALUE) {
@@ -5050,12 +5039,7 @@
             _PyFrame_StackPush(frame, retval);
             LOAD_SP();
             LOAD_IP(frame->return_offset);
-            #if LLTRACE && TIER_ONE
-            lltrace = maybe_lltrace_resume_frame(frame, &entry_frame, GLOBALS());
-            if (lltrace < 0) {
-                goto exit_unwind;
-            }
-            #endif
+            LLTRACE_RESUME_FRAME();
             DISPATCH();
         }
 
diff --git a/Python/optimizer.c b/Python/optimizer.c
index b17c2998e2504bf..e5c70f72f9c3247 100644
--- a/Python/optimizer.c
+++ b/Python/optimizer.c
@@ -697,7 +697,8 @@ translate_bytecode_to_trace(
                     // Reserve space for nuops (+ _SET_IP + _EXIT_TRACE)
                     int nuops = expansion->nuops;
                     RESERVE(nuops + 1); /* One extra for exit */
-                    if (expansion->uops[nuops-1].uop == _POP_FRAME) {
+                    int16_t last_op = expansion->uops[nuops-1].uop;
+                    if (last_op == _POP_FRAME || last_op == _RETURN_GENERATOR) {
                         // Check for trace stack underflow now:
                         // We can't bail e.g. in the middle of
                         // LOAD_CONST + _POP_FRAME.
@@ -756,7 +757,7 @@ translate_bytecode_to_trace(
                                 Py_FatalError("garbled expansion");
                         }
 
-                        if (uop == _POP_FRAME) {
+                        if (uop == _POP_FRAME || uop == _RETURN_GENERATOR) {
                             TRACE_STACK_POP();
                             /* Set the operand to the function or code object returned to,
                              * to assist optimization passes. (See _PUSH_FRAME below.)
diff --git a/Python/optimizer_analysis.c b/Python/optimizer_analysis.c
index a76edd62c94c131..9315d7228b57323 100644
--- a/Python/optimizer_analysis.c
+++ b/Python/optimizer_analysis.c
@@ -369,7 +369,7 @@ eliminate_pop_guard(_PyUOpInstruction *this_instr, bool exit)
 static PyCodeObject *
 get_code(_PyUOpInstruction *op)
 {
-    assert(op->opcode == _PUSH_FRAME || op->opcode == _POP_FRAME);
+    assert(op->opcode == _PUSH_FRAME || op->opcode == _POP_FRAME || op->opcode == _RETURN_GENERATOR);
     PyCodeObject *co = NULL;
     uint64_t operand = op->operand;
     if (operand == 0) {
diff --git a/Python/optimizer_bytecodes.c b/Python/optimizer_bytecodes.c
index 481fb8387af4167..8bc563427747905 100644
--- a/Python/optimizer_bytecodes.c
+++ b/Python/optimizer_bytecodes.c
@@ -651,6 +651,28 @@ dummy_func(void) {
         }
     }
 
+    op(_RETURN_GENERATOR, ( -- res)) {
+        SYNC_SP();
+        ctx->frame->stack_pointer = stack_pointer;
+        frame_pop(ctx);
+        stack_pointer = ctx->frame->stack_pointer;
+        OUT_OF_SPACE_IF_NULL(res = sym_new_unknown(ctx));
+
+        /* Stack space handling */
+        assert(corresponding_check_stack == NULL);
+        assert(co != NULL);
+        int framesize = co->co_framesize;
+        assert(framesize > 0);
+        assert(framesize <= curr_space);
+        curr_space -= framesize;
+
+        co = get_code(this_instr);
+        if (co == NULL) {
+            // might be impossible, but bailing is still safe
+            goto done;
+        }
+    }
+
     op(_CHECK_STACK_SPACE, ( --)) {
         assert(corresponding_check_stack == NULL);
         corresponding_check_stack = this_instr;
diff --git a/Python/optimizer_cases.c.h b/Python/optimizer_cases.c.h
index 0a7d96d30ad3e89..4f0941a3cc3e095 100644
--- a/Python/optimizer_cases.c.h
+++ b/Python/optimizer_cases.c.h
@@ -1840,6 +1840,29 @@
             break;
         }
 
+        case _RETURN_GENERATOR: {
+            _Py_UopsSymbol *res;
+            ctx->frame->stack_pointer = stack_pointer;
+            frame_pop(ctx);
+            stack_pointer = ctx->frame->stack_pointer;
+            OUT_OF_SPACE_IF_NULL(res = sym_new_unknown(ctx));
+            /* Stack space handling */
+            assert(corresponding_check_stack == NULL);
+            assert(co != NULL);
+            int framesize = co->co_framesize;
+            assert(framesize > 0);
+            assert(framesize <= curr_space);
+            curr_space -= framesize;
+            co = get_code(this_instr);
+            if (co == NULL) {
+                // might be impossible, but bailing is still safe
+                goto done;
+            }
+            stack_pointer[0] = res;
+            stack_pointer += 1;
+            break;
+        }
+
         case _BUILD_SLICE: {
             _Py_UopsSymbol *slice;
             slice = sym_new_not_null(ctx);
diff --git a/Tools/tsan/suppressions_free_threading.txt b/Tools/tsan/suppressions_free_threading.txt
index 1408103ba80f96f..e4ca32bebc5a22b 100644
--- a/Tools/tsan/suppressions_free_threading.txt
+++ b/Tools/tsan/suppressions_free_threading.txt
@@ -14,7 +14,6 @@ race:set_allocator_unlocked
 race:_add_to_weak_set
 race:_in_weak_set
 race:_mi_heap_delayed_free_partial
-race:_Py_IsImmortal
 race:_Py_IsOwnedByCurrentThread
 race:_PyEval_EvalFrameDefault
 race:_PyFunction_SetVersion
@@ -25,11 +24,10 @@ race:_PyInterpreterState_IsRunningMain
 race:_PyObject_GC_IS_SHARED
 race:_PyObject_GC_SET_SHARED
 race:_PyObject_GC_TRACK
+# https://gist.github.com/mpage/0a24eb2dd458441ededb498e9b0e5de8
+race:_PyParkingLot_Park
 race:_PyType_HasFeature
 race:assign_version_tag
-race:compare_unicode_unicode
-race:delitem_common
-race:dictresize
 race:gc_collect_main
 race:gc_restore_tid
 race:initialize_new_array
@@ -44,3 +42,6 @@ race:set_inheritable
 race:start_the_world
 race:tstate_set_detached
 race:unicode_hash
+
+# https://gist.github.com/mpage/6962e8870606cfc960e159b407a0cb40
+thread:pthread_create