bpo-38070: visit_decref() calls _PyObject_IsFreed() (GH-15782)

miss-islington · vstinner · web-flow · commit 5731172bb1e9 · 2019-09-09T10:18:09.000-07:00
In debug mode, visit_decref() now calls _PyObject_IsFreed() to ensure that the object is not freed. If it's freed, the program fails with an assertion error and Python dumps informations about the freed object. (cherry picked from commit d91d4de) Co-authored-by: Victor Stinner <vstinner@redhat.com>
diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c
@@ -376,6 +376,8 @@ static int
 visit_decref(PyObject *op, void *data)
 {
     assert(op != NULL);
+    _PyObject_ASSERT(op, !_PyObject_IsFreed(op));
+
     if (PyObject_IS_GC(op)) {
         PyGC_Head *gc = AS_GC(op);
         /* We're only interested in gc_refs for objects in the

Original file line number	Diff line number	Diff line change
`@@ -376,6 +376,8 @@ static int`
`376`	`376`	`visit_decref(PyObject op, void data)`
`377`	`377`	`{`
`378`	`378`	`assert(op != NULL);`
	`379`	`+ _PyObject_ASSERT(op, !_PyObject_IsFreed(op));`
	`380`	`+`
`379`	`381`	`if (PyObject_IS_GC(op)) {`
`380`	`382`	`PyGC_Head *gc = AS_GC(op);`
`381`	`383`	`/* We're only interested in gc_refs for objects in the`