bpo-1635741: Fix NULL ptr deref in multiprocessing (GH-22880)

tiran · web-flow · commit dde91b1953c0 · 2020-10-22T03:20:36.000-07:00
Commit 1d541c2 introduced a NULL pointer dereference in error path. Signed-off-by: Christian Heimes <christian@python.org>
diff --git a/Modules/_multiprocessing/multiprocessing.c b/Modules/_multiprocessing/multiprocessing.c
@@ -207,7 +207,6 @@ multiprocessing_exec(PyObject *module)
             py_sem_value_max = PyLong_FromLong(SEM_VALUE_MAX);
 
         if (py_sem_value_max == NULL) {
-            Py_DECREF(py_sem_value_max);
             return -1;
         }
         if (PyDict_SetItemString(_PyMp_SemLockType.tp_dict, "SEM_VALUE_MAX",

Original file line number	Diff line number	Diff line change
`@@ -207,7 +207,6 @@ multiprocessing_exec(PyObject *module)`
`207`	`207`	`py_sem_value_max = PyLong_FromLong(SEM_VALUE_MAX);`
`208`	`208`
`209`	`209`	`if (py_sem_value_max == NULL) {`
`210`		`- Py_DECREF(py_sem_value_max);`
`211`	`210`	`return -1;`
`212`	`211`	`}`
`213`	`212`	`if (PyDict_SetItemString(_PyMp_SemLockType.tp_dict, "SEM_VALUE_MAX",`