[Python-checkins] cpython (3.3): Issue 19158: a rare race in BoundedSemaphore could allow .release() too often.
tim.peters
python-checkins at python.org
Wed Oct 9 04:30:14 CEST 2013
http://hg.python.org/cpython/rev/e06edc0c7a49
changeset: 86165:e06edc0c7a49
branch: 3.3
parent: 86162:263001204b96
user: Tim Peters <tim at python.org>
date: Tue Oct 08 20:55:51 2013 -0500
summary:
Issue 19158: a rare race in BoundedSemaphore could allow .release() too often.
files:
Lib/test/test_threading.py | 18 ++++++++++++++++++
Lib/threading.py | 8 +++++---
2 files changed, 23 insertions(+), 3 deletions(-)
diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -468,6 +468,24 @@
self.assertEqual(0, status)
+ def test_BoundedSemaphore_limit(self):
+ # BoundedSemaphore should raise ValueError if released too often.
+ for limit in range(1, 10):
+ bs = threading.BoundedSemaphore(limit)
+ threads = [threading.Thread(target=bs.acquire)
+ for _ in range(limit)]
+ for t in threads:
+ t.start()
+ for t in threads:
+ t.join()
+ threads = [threading.Thread(target=bs.release)
+ for _ in range(limit)]
+ for t in threads:
+ t.start()
+ for t in threads:
+ t.join()
+ self.assertRaises(ValueError, bs.release)
+
class ThreadJoinOnShutdown(BaseTestCase):
# Between fork() and exec(), only async-safe functions are allowed (issues
diff --git a/Lib/threading.py b/Lib/threading.py
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -283,9 +283,11 @@
self._initial_value = value
def release(self):
- if self._value >= self._initial_value:
- raise ValueError("Semaphore released too many times")
- return Semaphore.release(self)
+ with self._cond:
+ if self._value >= self._initial_value:
+ raise ValueError("Semaphore released too many times")
+ self._value += 1
+ self._cond.notify()
class Event:
--
Repository URL: http://hg.python.org/cpython
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