diff --git a/yesod-core/src/Yesod/Core/Internal/Run.hs b/yesod-core/src/Yesod/Core/Internal/Run.hs
index 8f0afee9..759fa2bc 100644
--- a/yesod-core/src/Yesod/Core/Internal/Run.hs
+++ b/yesod-core/src/Yesod/Core/Internal/Run.hs
@@ -207,6 +207,9 @@ safeEh :: (Loc -> LogSource -> LogLevel -> LogStr -> IO ())
        -> ErrorResponse
        -> YesodApp
 safeEh log' er req = do
+    traceStack "safeEh debug trace, log':" log'
+    traceStack "safeEh debug trace, er:" er
+    traceStack "safeEh debug trace, req:" req
     liftIO $ log' $(qLocation >>= liftLoc) "yesod-core" LevelError
            $ toLogStr $ "Error handler errored out: " ++ show er
     return $ YRPlain