--- a/Lib/traceback.py	Tue Nov 11 21:13:28 2014 +0200
+++ b/Lib/traceback.py	Tue Nov 11 19:54:22 2014 +0000
@@ -3,6 +3,8 @@
 import linecache
 import sys
 import operator
+import collections
+import types
 
 __all__ = ['extract_stack', 'extract_tb', 'format_exception',
            'format_exception_only', 'format_list', 'format_stack',
@@ -50,10 +52,8 @@
 # - Line number
 # - Next item (same type as curr)
 # In practice, curr is either a traceback or a frame.
-def _extract_tb_or_stack_iter(curr, limit, extractor):
-    if limit is None:
-        limit = getattr(sys, 'tracebacklimit', None)
-
+def _extract_tb_or_stack_iter_raw(curr, limit, extractor):
+    # Yield (filename, lineno, name, f_globals) tuples
     n = 0
     while curr is not None and (limit is None or n < limit):
         f, lineno, next_item = extractor(curr)
@@ -61,18 +61,28 @@
         filename = co.co_filename
         name = co.co_name
 
-        linecache.checkcache(filename)
-        line = linecache.getline(filename, lineno, f.f_globals)
+        yield (filename, lineno, name, f.f_globals)
 
-        if line:
-            line = line.strip()
-        else:
-            line = None
-
-        yield (filename, lineno, name, line)
         curr = next_item
         n += 1
 
+def _extract_tb_or_stack_iter(curr, limit, extractor):
+    # Check if limit is negative
+    negative_limit = limit is not None and limit < 0
+
+    if limit is None or negative_limit:
+        _limit = getattr(sys, 'tracebacklimit', None)
+    else:
+        _limit = limit
+
+    raw = _extract_tb_or_stack_iter_raw(curr, _limit, extractor)
+    it = collections.deque(raw, maxlen=abs(limit)) if negative_limit else raw
+    
+    for filename, lineno, name, f_globals in it:
+        linecache.checkcache(filename)
+        line = linecache.getline(filename, lineno, f_globals)
+        yield (filename, lineno, name, line.strip() if line else None)
+
 def _extract_tb_iter(tb, limit):
     return _extract_tb_or_stack_iter(
                 tb, limit,
@@ -311,3 +321,4 @@
             # Ignore the exception raised if the frame is still executing.
             pass
         tb = tb.tb_next
+