Merged revisions 76117 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r76117 | antoine.pitrou | 2009-11-05 14:42:29 +0100 (jeu., 05 nov. 2009) | 5 lines
Issue #7264: Fix a possible deadlock when deallocating thread-local objects
which are part of a reference cycle.
........
diff --git a/Lib/_threading_local.py b/Lib/_threading_local.py
index 6d77035..6e8a8d8 100644
--- a/Lib/_threading_local.py
+++ b/Lib/_threading_local.py
@@ -217,10 +217,12 @@
key = object.__getattribute__(self, '_local__key')
try:
- threads = list(threading.enumerate())
+ # We use the non-locking API since we might already hold the lock
+ # (__del__ can be called at any point by the cyclic GC).
+ threads = threading._enumerate()
except:
- # If enumerate fails, as it seems to do during
- # shutdown, we'll skip cleanup under the assumption
+ # If enumerating the current threads fails, as it seems to do
+ # during shutdown, we'll skip cleanup under the assumption
# that there is nothing to clean up.
return
diff --git a/Lib/threading.py b/Lib/threading.py
index 88101b0..d5412e9 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -798,6 +798,10 @@
activeCount = active_count
+def _enumerate():
+ # Same as enumerate(), but without the lock. Internal use only.
+ return list(_active.values()) + list(_limbo.values())
+
def enumerate():
with _active_limbo_lock:
return list(_active.values()) + list(_limbo.values())
diff --git a/Misc/NEWS b/Misc/NEWS
index 1e2a79f..1e93aaa 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -123,6 +123,9 @@
Library
-------
+- Issue #7264: Fix a possible deadlock when deallocating thread-local objects
+ which are part of a reference cycle.
+
- Issue #7211: Allow 64-bit values for the `ident` and `data` fields of kevent
objects on 64-bit systems. Patch by Michael Broghton.