diff --git a/Lib/inspect.py b/Lib/inspect.py
index c489502..55d5316 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -435,7 +435,9 @@
     if info: return info[0]
 
 def getsourcefile(object):
-    """Return the Python source file an object was defined in, if it exists."""
+    """Return the filename that can be used to locate an object's source.
+    Return None if no way can be identified to get the source.
+    """
     filename = getfile(object)
     if filename[-4:].lower() in ('.pyc', '.pyo'):
         filename = filename[:-4] + '.py'
@@ -448,6 +450,9 @@
     # only return a non-existent filename if the module has a PEP 302 loader
     if hasattr(getmodule(object, filename), '__loader__'):
         return filename
+    # or it is in the linecache
+    if filename in linecache.cache:
+        return filename
 
 def getabsfile(object, _filename=None):
     """Return an absolute path to the source or compiled file for an object.