gh-151126: Fix a possible crash during the startup with no memory under Py_STACKREF_DEBUG

Author: sobolevn

Misc/NEWS.d/next/Library/2026-06-28-13-05-52.gh-issue-151126.KE2OvV.rst

@@ -0,0 +1,2 @@
+Fix a possible crash during the interpreter startup under a memory pressure
+with ``Py_STACKREF_DEBUG`` enabled.

Python/pystate.c

@@ -656,6 +656,9 @@ init_interpreter(PyInterpreterState *interp,
         NULL,
         &alloc
     );
+    if (interp->open_stackrefs_table == NULL) {
+        return _PyStatus_NO_MEMORY();
+    }
 #  ifdef Py_STACKREF_CLOSE_DEBUG
     interp->closed_stackrefs_table = _Py_hashtable_new_full(
         _Py_hashtable_hash_ptr,
@@ -664,6 +667,9 @@ init_interpreter(PyInterpreterState *interp,
         NULL,
         &alloc
     );
+    if (interp->closed_stackrefs_table == NULL) {
+        return _PyStatus_NO_MEMORY();
+    }
 #  endif
     _Py_stackref_associate(interp, Py_None, PyStackRef_None);
     _Py_stackref_associate(interp, Py_False, PyStackRef_False);