Apply Victor's suggestions

Co-authored-by: Victor Stinner <victor.stinner@gmail.com>

Author: StanFromIreland

Include/pyport.h

@@ -558,7 +558,7 @@ extern "C" {
 #      define _Py_MEMORY_SANITIZER
 #      define _Py_NO_SANITIZE_MEMORY __attribute__((no_sanitize_memory))
 #      define _Py_MSAN_UNPOISON(PTR, SIZE)  (__msan_unpoison(PTR, SIZE))
-#      define _Py_MSAN_UNPOISON_STRING(PTR)  (__msan_unpoison_string(PTR))
+#      define _Py_MSAN_UNPOISON_STRING(STR)  (__msan_unpoison_string(STR))
 #    endif
 #  endif
 #  if __has_feature(address_sanitizer)
@@ -601,7 +601,7 @@ extern "C" {
 #  define _Py_MSAN_UNPOISON(PTR, SIZE)
 #endif
 #ifndef _Py_MSAN_UNPOISON_STRING
-#  define _Py_MSAN_UNPOISON_STRING(PTR)
+#  define _Py_MSAN_UNPOISON_STRING(STR)
 #endif
 
 /* AIX has __bool__ redefined in it's system header file. */

Lib/test/test_faulthandler.py

@@ -34,8 +34,8 @@
 
 
 def skip_if_sanitizer_signal(signame):
-    return support.skip_if_sanitizer(f"TSAN/UBSan itercepts {signame}",
-                                     thread=True, ub=True)
+    return support.skip_if_sanitizer(f"TSan/UBSan/MSan intercepts {signame}",
+                                     thread=True, ub=True, memory=True)
 
 
 def expected_traceback(lineno1, lineno2, header, min_count=1):

Modules/socketmodule.c

@@ -763,7 +763,6 @@ set_error(void)
 static PyObject *
 decode_error_message(const char *str)
 {
-    _Py_MSAN_UNPOISON_STRING(str);
     return PyUnicode_DecodeLocale(str, "surrogateescape");
 }
 #endif
@@ -775,7 +774,9 @@ set_herror(socket_state *state, int h_error)
     PyObject *v;
 
 #ifdef HAVE_HSTRERROR
-    v = Py_BuildValue("(iN)", h_error, decode_error_message(hstrerror(h_error)));
+    const char *errmsg = hstrerror(h_error);
+    _Py_MSAN_UNPOISON_STRING(errmsg);
+    v = Py_BuildValue("(iN)", h_error, decode_error_message(errmsg));
 #else
     v = Py_BuildValue("(is)", h_error, "host not found");
 #endif
@@ -802,7 +803,9 @@ set_gaierror(socket_state *state, int error)
 #endif
 
 #ifdef HAVE_GAI_STRERROR
-    v = Py_BuildValue("(iN)", error, decode_error_message(gai_strerror(error)));
+    const char *errmsg = gai_strerror(error);
+    _Py_MSAN_UNPOISON_STRING(errmsg);
+    v = Py_BuildValue("(iN)", error, decode_error_message(errmsg));
 #else
     v = Py_BuildValue("(is)", error, "getaddrinfo failed");
 #endif