diff -r adc2f5003ea3 Lib/test/test_exceptions.py
--- a/Lib/test/test_exceptions.py	Sat Mar 29 06:06:52 2008 +0100
+++ b/Lib/test/test_exceptions.py	Sat Mar 29 15:34:49 2008 +0100
@@ -4,6 +4,8 @@ import sys
 import sys
 import unittest
 import pickle
+import threading
+import weakref
 
 from test.test_support import TESTFN, unlink, run_unittest
 
@@ -410,6 +412,54 @@ class ExceptionTests(unittest.TestCase):
             del e
         self.failIf('e' in locals())
 
+    def testExceptionCleanupThreading(self):
+        # Make sure exception state is really cleaned up, even if we switch
+        # threads before destroying the frame where the exception was raised.
+        # See #2507
+
+        class MyException(Exception):
+            def __init__(self, obj):
+                self.obj = obj
+        class MyObj:
+            pass
+
+        def inner_raising_func():
+            # Create some references in exception value and traceback
+            local_ref = obj
+            raise MyException(obj)
+
+        def raising_func():
+            try:
+                inner_raising_func()
+            except MyException as e:
+                pass
+            with cond:
+                cond.notifyAll()
+            # Give back control to the main thread
+            with block:
+                pass
+
+        obj = MyObj()
+        wr = weakref.ref(obj)
+        cond = threading.Condition()
+        cond.acquire()
+        block = threading.Lock()
+
+        t = threading.Thread(target=raising_func)
+        try:
+            block.acquire()
+            t.start()
+            cond.wait()
+            # The last references to the instance shall now die
+            obj = None
+            obj = wr()
+            self.failUnless(obj is None, "%s" % obj)
+        finally:
+            cond.release()
+            # Endly, raising_func() can return and destroy its frame
+            block.release()
+            t.join(1.0)
+
 
 def test_main():
     run_unittest(ExceptionTests)
diff -r adc2f5003ea3 Python/ceval.c
--- a/Python/ceval.c	Sat Mar 29 06:06:52 2008 +0100
+++ b/Python/ceval.c	Sat Mar 29 15:34:49 2008 +0100
@@ -1477,6 +1477,18 @@ PyEval_EvalFrameEx(PyFrameObject *f, int
 					"'finally' pops bad exception");
 				why = WHY_EXCEPTION;
 			}
+			/*
+				Make sure the exception state is cleaned up, even if there
+				is a thread switch before we leave the frame. This ensures
+				references to the exception state are not kept too long.
+				See #2507.
+			*/
+			if (tstate->frame->f_exc_type != NULL)
+				reset_exc_info(tstate);
+			else {
+				assert(tstate->frame->f_exc_value == NULL);
+				assert(tstate->frame->f_exc_traceback == NULL);
+			}
 			Py_DECREF(v);
 			break;