diff --git a/snap-server.cabal b/snap-server.cabal
--- a/snap-server.cabal
+++ b/snap-server.cabal
@@ -1,5 +1,5 @@
 name:           snap-server
-version:        1.0.2.1
+version:        1.0.2.2
 synopsis:       A web server for the Snap Framework
 description:
   Snap is a simple and fast web development framework and server written in
diff --git a/src/Snap/Internal/Http/Server/Session.hs b/src/Snap/Internal/Http/Server/Session.hs
--- a/src/Snap/Internal/Http/Server/Session.hs
+++ b/src/Snap/Internal/Http/Server/Session.hs
@@ -192,8 +192,10 @@
             connClose <- newIORef False
             newConn   <- newIORef True
             let twiddleTimeout = unsafePerformIO $ do
-                    th <- readMVar thMVar
-                    return $ TM.modify th
+                                   th <- readMVar thMVar
+                                   return $! TM.modify th
+            let cleanupTimeout = do th <- readMVar thMVar
+                                    return $! TM.cancel th
 
             let !psd = PerSessionData connClose
                                       twiddleTimeout
@@ -205,7 +207,9 @@
                                       remotePort
                                       readEnd
                                       writeEnd
-            restore (session psd) `E.finally` cleanup
+            restore (session psd)
+                `E.finally` cleanup
+                `E.finally` cleanupTimeout
 
     --------------------------------------------------------------------------
     session psd = do
diff --git a/src/Snap/Internal/Http/Server/TimeoutManager.hs b/src/Snap/Internal/Http/Server/TimeoutManager.hs
--- a/src/Snap/Internal/Http/Server/TimeoutManager.hs
+++ b/src/Snap/Internal/Http/Server/TimeoutManager.hs
@@ -19,10 +19,10 @@
 ------------------------------------------------------------------------------
 import           Control.Exception                (evaluate, finally)
 import qualified Control.Exception                as E
-import           Control.Monad                    (Monad ((>>=), return), mapM_, void, when)
+import           Control.Monad                    (Monad (return, (>>=)), mapM_, void, when)
 import qualified Data.ByteString.Char8            as S
 import           Data.IORef                       (IORef, newIORef, readIORef, writeIORef)
-import           Prelude                          (Bool, Double, IO, Int, Show (..), const, fromIntegral, max,  null, otherwise, round, ($), ($!), (+), (++), (-), (.), (<=), (==))
+import           Prelude                          (Bool, Double, IO, Int, Show (..), const, fromIntegral, max, null, otherwise, round, ($), ($!), (+), (++), (-), (.), (<=), (==))
 ------------------------------------------------------------------------------
 import           Control.Concurrent               (MVar, newEmptyMVar, putMVar, readMVar, takeMVar, tryPutMVar)
 ------------------------------------------------------------------------------
@@ -172,8 +172,8 @@
 -- | Cancel a timeout.
 cancel :: TimeoutThread -> IO ()
 cancel h = E.uninterruptibleMask_ $ do
-    T.cancel $ _thread h
     writeIORef (_state h) canceled
+    T.cancel $ _thread h
 {-# INLINE cancel #-}