[Python-checkins] cpython (merge 3.3 -> default): Issue 19158: a rare race in BoundedSemaphore could allow .release() too often.
tim.peters
python-checkins at python.org
Wed Oct 9 04:30:16 CEST 2013
http://hg.python.org/cpython/rev/7c56bf5afee6
changeset: 86166:7c56bf5afee6
parent: 86164:1cbd3d9f7d61
parent: 86165:e06edc0c7a49
user: Tim Peters <tim at python.org>
date: Tue Oct 08 21:12:58 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
@@ -599,6 +599,24 @@
time.sleep(0.01)
self.assertIn(LOOKING_FOR, repr(t)) # we waited at least 5 seconds
+ 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):
def _run_and_join(self, script):
diff --git a/Lib/threading.py b/Lib/threading.py
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -289,9 +289,11 @@
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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