diff --git a/zuul/scheduler.py b/zuul/scheduler.py
index 30a6c81..beab879 100644
--- a/zuul/scheduler.py
+++ b/zuul/scheduler.py
@@ -20,6 +20,7 @@
 import logging
 import os
 import pickle
+import six
 from six.moves import queue as Queue
 import re
 import sys
@@ -125,12 +126,10 @@
     """An event that should be processed within the main queue run loop"""
     def __init__(self):
         self._wait_event = threading.Event()
-        self._exception = None
-        self._traceback = None
+        self._exc_info = None
 
-    def exception(self, e, tb):
-        self._exception = e
-        self._traceback = tb
+    def exception(self, exc_info):
+        self._exc_info = exc_info
         self._wait_event.set()
 
     def done(self):
@@ -138,8 +137,8 @@
 
     def wait(self, timeout=None):
         self._wait_event.wait(timeout)
-        if self._exception:
-            raise self._exception, None, self._traceback
+        if self._exc_info:
+            six.reraise(*self._exc_info)
         return self._wait_event.is_set()
 
 
@@ -1053,8 +1052,8 @@
             else:
                 self.log.error("Unable to handle event %s" % event)
             event.done()
-        except Exception as e:
-            event.exception(e, sys.exc_info()[2])
+        except Exception:
+            event.exception(sys.exc_info())
         self.management_event_queue.task_done()
 
     def process_result_queue(self):