Deopt if not owned, and mark as shared in specializer

Author: DinoV

Python/bytecodes.c

@@ -2287,7 +2287,7 @@ dummy_func(
             PyDictKeysObject *dk = FT_ATOMIC_LOAD_PTR(dict->ma_keys);
             assert(PyDict_CheckExact((PyObject *)dict));
 #ifdef Py_GIL_DISABLED
-            _PyDict_EnsureSharedOnRead(dict);
+            DEOPT_IF(!_Py_IsOwnedByCurrentThread((PyObject *)dict) && !_PyObject_GC_IS_SHARED(dict));
 #endif
             PyObject *attr_o;
             if (hint >= (size_t)FT_ATOMIC_LOAD_SSIZE_RELAXED(dk->dk_nentries)) {

Python/executor_cases.c.h

@@ -1009,6 +1009,9 @@ specialize_dict_access_hint(
     _PyAttrCache *cache = (_PyAttrCache *)(instr + 1);
 
     _Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(dict);
+#ifdef Py_GIL_DISABLED
+    _PyDict_EnsureSharedOnRead(dict);
+#endif
 
     // We found an instance with a __dict__.
     if (_PyDict_HasSplitTable(dict)) {