From b53f61a3050e380ca1936671c5e11aedbbb7eb7c Mon Sep 17 00:00:00 2001
From: meowmeowmeowcat <meowmeowcat1211@gmail.com>
Date: Wed, 18 Aug 2021 06:55:04 +0800
Subject: [PATCH] bpo-44508: [Doc] Document failure mode for
 loop.call_soon_threadsafe (GH-27688)
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Co-authored-by: Łukasz Langa <lukasz@langa.pl>
(cherry picked from commit 3240bc62f4e0afa09964f3afc845697f0a0806b9)

Co-authored-by: meowmeowmeowcat <meowmeowcat1211@gmail.com>
---
 Doc/library/asyncio-eventloop.rst | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Doc/library/asyncio-eventloop.rst b/Doc/library/asyncio-eventloop.rst
index 66eb3faecd896e..4a64475f2a939e 100644
--- a/Doc/library/asyncio-eventloop.rst
+++ b/Doc/library/asyncio-eventloop.rst
@@ -211,6 +211,10 @@ Scheduling callbacks
    A thread-safe variant of :meth:`call_soon`.  Must be used to
    schedule callbacks *from another thread*.
 
+   Raises :exc:`RuntimeError` if called on a loop that's been closed.
+   This can happen on a secondary thread when the main application is
+   shutting down.
+
    See the :ref:`concurrency and multithreading <asyncio-multithreading>`
    section of the documentation.