diff -r 3486425ed82b Lib/test/test_asyncio/test_tasks.py
--- a/Lib/test/test_asyncio/test_tasks.py	Fri Jan 13 19:18:33 2017 +0000
+++ b/Lib/test/test_asyncio/test_tasks.py	Fri Jan 13 17:17:17 2017 -0500
@@ -1461,6 +1461,14 @@
         def coro(loop):
             self.assertTrue(Task.current_task(loop=loop) is task)
 
+            # See http://bugs.python.org/issue29271 for details:
+            asyncio.set_event_loop(loop)
+            try:
+                self.assertTrue(Task.current_task(None) is task)
+                self.assertTrue(Task.current_task() is task)
+            finally:
+                asyncio.set_event_loop(None)
+
         task = self.new_task(self.loop, coro(self.loop))
         self.loop.run_until_complete(task)
         self.assertIsNone(Task.current_task(loop=self.loop))
@@ -1805,8 +1813,17 @@
         # schedule the task
         coro = kill_me(self.loop)
         task = asyncio.ensure_future(coro, loop=self.loop)
+
         self.assertEqual(Task.all_tasks(loop=self.loop), {task})
 
+        # See http://bugs.python.org/issue29271 for details:
+        asyncio.set_event_loop(self.loop)
+        try:
+            self.assertEqual(Task.all_tasks(), {task})
+            self.assertEqual(Task.all_tasks(None), {task})
+        finally:
+            asyncio.set_event_loop(None)
+
         # execute the task so it waits for future
         self.loop._run_once()
         self.assertEqual(len(self.loop._ready), 0)
diff -r 3486425ed82b Modules/_asynciomodule.c
--- a/Modules/_asynciomodule.c	Fri Jan 13 19:18:33 2017 +0000
+++ b/Modules/_asynciomodule.c	Fri Jan 13 17:17:17 2017 -0500
@@ -1414,7 +1414,7 @@
 @classmethod
 _asyncio.Task.current_task
 
-    loop: 'O' = NULL
+    loop: 'O' = None
 
 Return the currently running task in an event loop or None.
 
@@ -1425,11 +1425,11 @@
 
 static PyObject *
 _asyncio_Task_current_task_impl(PyTypeObject *type, PyObject *loop)
-/*[clinic end generated code: output=99fbe7332c516e03 input=cd784537f02cf833]*/
+/*[clinic end generated code: output=99fbe7332c516e03 input=a0d6cdf2e3b243e1]*/
 {
     PyObject *res;
 
-    if (loop == NULL) {
+    if (loop == Py_None) {
         loop = _PyObject_CallNoArg(asyncio_get_event_loop);
         if (loop == NULL) {
             return NULL;
@@ -1501,7 +1501,7 @@
 @classmethod
 _asyncio.Task.all_tasks
 
-    loop: 'O' = NULL
+    loop: 'O' = None
 
 Return a set of all tasks for an event loop.
 
@@ -1510,11 +1510,11 @@
 
 static PyObject *
 _asyncio_Task_all_tasks_impl(PyTypeObject *type, PyObject *loop)
-/*[clinic end generated code: output=11f9b20749ccca5d input=cd64aa5f88bd5c49]*/
+/*[clinic end generated code: output=11f9b20749ccca5d input=c6f5b53bd487488f]*/
 {
     PyObject *res;
 
-    if (loop == NULL) {
+    if (loop == Py_None) {
         loop = _PyObject_CallNoArg(asyncio_get_event_loop);
         if (loop == NULL) {
             return NULL;
diff -r 3486425ed82b Modules/clinic/_asynciomodule.c.h
--- a/Modules/clinic/_asynciomodule.c.h	Fri Jan 13 19:18:33 2017 +0000
+++ b/Modules/clinic/_asynciomodule.c.h	Fri Jan 13 17:17:17 2017 -0500
@@ -278,7 +278,7 @@
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"loop", NULL};
     static _PyArg_Parser _parser = {"|O:current_task", _keywords, 0};
-    PyObject *loop = NULL;
+    PyObject *loop = Py_None;
 
     if (!_PyArg_ParseStack(args, nargs, kwnames, &_parser,
         &loop)) {
@@ -310,7 +310,7 @@
     PyObject *return_value = NULL;
     static const char * const _keywords[] = {"loop", NULL};
     static _PyArg_Parser _parser = {"|O:all_tasks", _keywords, 0};
-    PyObject *loop = NULL;
+    PyObject *loop = Py_None;
 
     if (!_PyArg_ParseStack(args, nargs, kwnames, &_parser,
         &loop)) {
@@ -517,4 +517,4 @@
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=8f036321bb083066 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=40ca6c9da517da73 input=a9049054013a1b77]*/