From fccf4cb7f430d8278796e273dde44c275bfac042 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Sat, 25 Jan 2025 16:51:11 +0100
Subject: [PATCH 1/3] fix UBSan failures for `OverlappedObject`

---
 Modules/_winapi.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/Modules/_winapi.c b/Modules/_winapi.c
index 260cab48091c16..28e9765431f5ba 100644
--- a/Modules/_winapi.c
+++ b/Modules/_winapi.c
@@ -144,14 +144,17 @@ typedef struct {
     Py_buffer write_buffer;
 } OverlappedObject;
 
+#define _OverlappedObject_CAST(op)  ((OverlappedObject *)(op))
+
 /*
 Note: tp_clear (overlapped_clear) is not implemented because it
 requires cancelling the IO operation if it's pending and the cancellation is
 quite complex and can fail (see: overlapped_dealloc).
 */
 static int
-overlapped_traverse(OverlappedObject *self, visitproc visit, void *arg)
+overlapped_traverse(PyObject *op, visitproc visit, void *arg)
 {
+    OverlappedObject *self = _OverlappedObject_CAST(op);
     Py_VISIT(self->read_buffer);
     Py_VISIT(self->write_buffer.obj);
     Py_VISIT(Py_TYPE(self));
@@ -159,10 +162,11 @@ overlapped_traverse(OverlappedObject *self, visitproc visit, void *arg)
 }
 
 static void
-overlapped_dealloc(OverlappedObject *self)
+overlapped_dealloc(PyObject *op)
 {
     DWORD bytes;
     int err = GetLastError();
+    OverlappedObject *self = _OverlappedObject_CAST(op);
 
     PyObject_GC_UnTrack(self);
     if (self->pending) {

From c38e3d39b06bd81910dc0e446a892128e556fe44 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Sat, 25 Jan 2025 16:51:18 +0100
Subject: [PATCH 2/3] suppress unused return values

---
 Modules/_winapi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Modules/_winapi.c b/Modules/_winapi.c
index 28e9765431f5ba..ef8fbcd7d51b8d 100644
--- a/Modules/_winapi.c
+++ b/Modules/_winapi.c
@@ -3220,7 +3220,7 @@ winapi_clear(PyObject *module)
 static void
 winapi_free(void *module)
 {
-    winapi_clear((PyObject *)module);
+    (void)winapi_clear((PyObject *)module);
 }
 
 static struct PyModuleDef winapi_module = {

From 72737d076ac4358ba60063a95c7599fff620040c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Sat, 8 Feb 2025 10:21:13 +0100
Subject: [PATCH 3/3] Do Do not use `_` + capital letter in new code as it is
 also UB.

---
 Modules/_winapi.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Modules/_winapi.c b/Modules/_winapi.c
index 78a947568c32ac..4391bfc09f9cb8 100644
--- a/Modules/_winapi.c
+++ b/Modules/_winapi.c
@@ -144,7 +144,7 @@ typedef struct {
     Py_buffer write_buffer;
 } OverlappedObject;
 
-#define _OverlappedObject_CAST(op)  ((OverlappedObject *)(op))
+#define OverlappedObject_CAST(op)   ((OverlappedObject *)(op))
 
 /*
 Note: tp_clear (overlapped_clear) is not implemented because it
@@ -154,7 +154,7 @@ quite complex and can fail (see: overlapped_dealloc).
 static int
 overlapped_traverse(PyObject *op, visitproc visit, void *arg)
 {
-    OverlappedObject *self = _OverlappedObject_CAST(op);
+    OverlappedObject *self = OverlappedObject_CAST(op);
     Py_VISIT(self->read_buffer);
     Py_VISIT(self->write_buffer.obj);
     Py_VISIT(Py_TYPE(self));
@@ -166,7 +166,7 @@ overlapped_dealloc(PyObject *op)
 {
     DWORD bytes;
     int err = GetLastError();
-    OverlappedObject *self = _OverlappedObject_CAST(op);
+    OverlappedObject *self = OverlappedObject_CAST(op);
 
     PyObject_GC_UnTrack(self);
     if (self->pending) {