[3.15] gh-151126: Sets missing exceptions in tkinter and socket modules initializations (GH-152418) (#152420)

gh-151126: Sets missing exceptions in `tkinter` and `socket` modules initializations (GH-152418)
(cherry picked from commit a9fa856)

Co-authored-by: sobolevn <mail@sobolevn.me>

Author: miss-islington

Misc/NEWS.d/next/Library/2026-06-27-17-19-09.gh-issue-151126.huUyOM.rst

@@ -0,0 +1,2 @@
+Fix two crashes in :mod:`tkinter` and :mod:`socket` modules initialization
+under a memory pressure. Sets missing :exc:`MemoryError`.

Modules/_tkinter.c

@@ -3574,7 +3574,7 @@ PyInit__tkinter(void)
 
     tcl_lock = PyThread_allocate_lock();
     if (tcl_lock == NULL)
-        return NULL;
+        return PyErr_NoMemory();
 
     m = PyModule_Create(&_tkintermodule);
     if (m == NULL)

Modules/socketmodule.c

@@ -9288,6 +9288,7 @@ socket_exec(PyObject *m)
 #if defined(USE_GETHOSTBYNAME_LOCK)
     netdb_lock = PyThread_allocate_lock();
     if (netdb_lock == NULL) {
+        PyErr_NoMemory();
         goto error;
     }
 #endif