From: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Date: Thu, 26 Jun 2025 14:26:11 +0000 (+0200)
Subject: [3.13] gh-91555: add warning to docs about possibility of deadlock/infinite recursion... 
X-Git-Tag: v3.13.6~171
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3be3c496df3d2ab48d1c66031b9fc78550b3a2a6;p=thirdparty%2FPython%2Fcpython.git

[3.13] gh-91555: add warning to docs about possibility of deadlock/infinite recursion (GH-135954) (GH-135989)

(cherry picked from commit a4625d597f9fc2d083fbb9c22d3ffcec73b2061a)
---

diff --git a/Doc/library/logging.handlers.rst b/Doc/library/logging.handlers.rst
index b48c5cb483dc..c587052ae9a4 100644
--- a/Doc/library/logging.handlers.rst
+++ b/Doc/library/logging.handlers.rst
@@ -1052,6 +1052,15 @@ possible, while any potentially slow operations (such as sending an email via
    .. note:: If you are using :mod:`multiprocessing`, you should avoid using
       :class:`~queue.SimpleQueue` and instead use :class:`multiprocessing.Queue`.
 
+   .. warning::
+
+      The :mod:`multiprocessing` module uses an internal logger created and
+      accessed via :meth:`~multiprocessing.get_logger`.
+      :class:`multiprocessing.Queue` will log ``DEBUG`` level messages upon
+      items being queued. If those log messages are processed by a
+      :class:`QueueHandler` using the same :class:`multiprocessing.Queue` instance,
+      it will cause a deadlock or infinite recursion.
+
    .. method:: emit(record)
 
       Enqueues the result of preparing the LogRecord. Should an exception