[Python-checkins] r76120 - in python/branches/release31-maint: Lib/_threading_local.py Lib/threading.py Misc/NEWS

[antoine.pitrou]

Author: antoine.pitrou
Date: Thu Nov  5 14:51:19 2009
New Revision: 76120

Log:
Merged revisions 76119 via svnmerge from 
svn+ssh://pythondev@svn.python.org/python/branches/py3k

................
  r76119 | antoine.pitrou | 2009-11-05 14:49:14 +0100 (jeu., 05 nov. 2009) | 10 lines
  
  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.
  ........
................


Modified:
   python/branches/release31-maint/   (props changed)
   python/branches/release31-maint/Lib/_threading_local.py
   python/branches/release31-maint/Lib/threading.py
   python/branches/release31-maint/Misc/NEWS

Modified: python/branches/release31-maint/Lib/_threading_local.py
==============================================================================
--- python/branches/release31-maint/Lib/_threading_local.py	(original)
+++ python/branches/release31-maint/Lib/_threading_local.py	Thu Nov  5 14:51:19 2009
@@ -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
 

Modified: python/branches/release31-maint/Lib/threading.py
==============================================================================
--- python/branches/release31-maint/Lib/threading.py	(original)
+++ python/branches/release31-maint/Lib/threading.py	Thu Nov  5 14:51:19 2009
@@ -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())

Modified: python/branches/release31-maint/Misc/NEWS
==============================================================================
--- python/branches/release31-maint/Misc/NEWS	(original)
+++ python/branches/release31-maint/Misc/NEWS	Thu Nov  5 14:51:19 2009
@@ -40,6 +40,9 @@
 Library
 -------
 
+- Issue #7264: Fix a possible deadlock when deallocating thread-local objects
+  which are part of a reference cycle.
+
 - Issue #6896: mailbox.Maildir now invalidates its internal cache each time
   a modification is done through it.  This fixes inconsistencies and test
   failures on systems with slightly bogus mtime behaviour.