- rel 2; fixes some multiprocessing hang - https://bugs.python.org/issue38744

diff --git a/bug-38744.patch b/bug-38744.patch
new file mode 100644 (file)
index 0000000..259b547
--- /dev/null
+++ b/bug-38744.patch
@@ -0,0 +1,90 @@
+From ef8bff34231bb9c74fe349905bc29b5be8a48325 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Batuhan=20Ta=C5=9Fkaya?=
+ <47358913+isidentical@users.noreply.github.com>
+Date: Sun, 15 Mar 2020 22:45:56 +0300
+Subject: [PATCH] bpo-39360: Ensure all workers exit when finalizing a
+ multiprocessing Pool (GH-19009)
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+When the pull is not used via the context manager or terminate() is called, there is a system in multiprocessing.util that handles finalization of all pools via an atexit handler (the Finalize) class. This class registers the _terminate_pool handler in the registry of finalizers of the module, and that registry is called on interpreter exit via _exit_function. The problem is that the "happy" path with the context manager or manual call to finalize() does some extra steps that _terminate_pool does not. The step that is not executed when the atexit() handler calls _terminate_pool is pinging the _change_notifier queue to unblock the maintenance threads.
+
+This commit moves the notification to the _terminate_pool function so is called from both code paths.
+
+Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
+(cherry picked from commit ac10e0c93218627d1a639db0b7b41714c5f6a883)
+
+Co-authored-by: Batuhan Taşkaya <47358913+isidentical@users.noreply.github.com>
+---
+ Lib/multiprocessing/pool.py                    |  7 +++++--
+ Lib/test/_test_multiprocessing.py              | 18 ++++++++++++++++++
+ .../2020-03-15-05-41-05.bpo-39360.cmcU5p.rst   |  4 ++++
+ 3 files changed, 27 insertions(+), 2 deletions(-)
+ create mode 100644 Misc/NEWS.d/next/Library/2020-03-15-05-41-05.bpo-39360.cmcU5p.rst
+
+diff --git a/Lib/multiprocessing/pool.py b/Lib/multiprocessing/pool.py
+index b223d6aa724bb..41dd923d4f974 100644
+--- a/Lib/multiprocessing/pool.py
++++ b/Lib/multiprocessing/pool.py
+@@ -651,8 +651,6 @@ def close(self):
+     def terminate(self):
+         util.debug('terminating pool')
+         self._state = TERMINATE
+-        self._worker_handler._state = TERMINATE
+-        self._change_notifier.put(None)
+         self._terminate()
+ 
+     def join(self):
+@@ -682,7 +680,12 @@ def _terminate_pool(cls, taskqueue, inqueue, outqueue, pool, change_notifier,
+         # this is guaranteed to only be called once
+         util.debug('finalizing pool')
+ 
++        # Notify that the worker_handler state has been changed so the
++        # _handle_workers loop can be unblocked (and exited) in order to
++        # send the finalization sentinel all the workers.
+         worker_handler._state = TERMINATE
++        change_notifier.put(None)
++
+         task_handler._state = TERMINATE
+ 
+         util.debug('helping task handler/workers to finish')
+diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
+index de912428737f9..e64a8e9b3b879 100644
+--- a/Lib/test/_test_multiprocessing.py
++++ b/Lib/test/_test_multiprocessing.py
+@@ -2778,6 +2778,24 @@ def test_pool_worker_lifetime_early_close(self):
+         for (j, res) in enumerate(results):
+             self.assertEqual(res.get(), sqr(j))
+ 
++    def test_worker_finalization_via_atexit_handler_of_multiprocessing(self):
++        # tests cases against bpo-38744 and bpo-39360
++        cmd = '''if 1:
++            from multiprocessing import Pool
++            problem = None
++            class A:
++                def __init__(self):
++                    self.pool = Pool(processes=1)
++            def test():
++                global problem
++                problem = A()
++                problem.pool.map(float, tuple(range(10)))
++            if __name__ == "__main__":
++                test()
++        '''
++        rc, out, err = test.support.script_helper.assert_python_ok('-c', cmd)
++        self.assertEqual(rc, 0)
++
+ #
+ # Test of creating a customized manager class
+ #
+diff --git a/Misc/NEWS.d/next/Library/2020-03-15-05-41-05.bpo-39360.cmcU5p.rst b/Misc/NEWS.d/next/Library/2020-03-15-05-41-05.bpo-39360.cmcU5p.rst
+new file mode 100644
+index 0000000000000..148878886e6ee
+--- /dev/null
++++ b/Misc/NEWS.d/next/Library/2020-03-15-05-41-05.bpo-39360.cmcU5p.rst
+@@ -0,0 +1,4 @@
++Ensure all workers exit when finalizing a :class:`multiprocessing.Pool` implicitly via the module finalization
++handlers of multiprocessing. This fixes a deadlock situation that can be experienced when the Pool is not
++properly finalized via the context manager or a call to ``multiprocessing.Pool.terminate``. Patch by Batuhan Taskaya
++and Pablo Galindo.

diff --git a/python3.spec b/python3.spec
index c4f7db782c77861fddd8089eee9406bf50a97a9a..c32bb2db6e3df0d7935c1ceecf6eac9eb8c5a1d9 100644 (file)
--- a/python3.spec
+++ b/python3.spec
@@ -42,7 +42,7 @@ Summary(tr.UTF-8):    X arayüzlü, yüksek düzeyli, kabuk yorumlayıcı dili
 Summary(uk.UTF-8):     Мова програмування дуже високого рівня з X-інтерфейсом
 Name:          python3
 Version:       %{py_ver}.2
-Release:       1
+Release:       2
 Epoch:         1
 License:       PSF
 Group:         Development/Languages/Python
@@ -55,7 +55,7 @@ Patch2:               %{name}-multilib.patch
 Patch3:                %{name}-no_cmdline_tests.patch
 Patch4:                %{name}-makefile-location.patch
 Patch5:                %{name}-config.patch
-
+Patch6:                bug-38744.patch
 Patch7:                %{name}-db.patch
 Patch8:                %{name}-install_prefix.patch
 Patch9:                %{name}-tests_with_pythonpath.patch
@@ -490,7 +490,7 @@ Moduły testowe dla Pythona.
 %patch3 -p1
 %patch4 -p1
 %patch5 -p1
-
+%patch6 -p1
 %patch7 -p1
 %patch8 -p1
 %patch9 -p1