diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,15 @@
+## Version 2.7.0.2
+
+* Removing withMVar to avoid the deadlock between "accept" and "close"
+   [#330](https://github.com/haskell/network/pull/330)
+* "close" does not throw exceptions. A new API: "close'" throws
+   exceptions when necessary.
+   [#337](https://github.com/haskell/network/pull/337)
+* Fixing the hang of lazy sendAll.
+   [#340](https://github.com/haskell/network/pull/340)
+* Installing NetDef.h (#334)
+   [#334](https://github.com/haskell/network/pull/334)
+
 ## Version 2.7.0.1
 
  * A new API: socketPortSafe.
diff --git a/Network/Socket.hsc b/Network/Socket.hsc
--- a/Network/Socket.hsc
+++ b/Network/Socket.hsc
@@ -88,6 +88,12 @@
 -- >         msg <- recv sock 1024
 -- >         putStr "Received: "
 -- >         C.putStrLn msg
+--
+-- The proper programming model is that one 'Socket' is handled by
+-- a single thread. If multiple threads use one 'Socket' concurrently,
+-- unexpected things would happen. There is one exception for multiple
+-- threads vs a single 'Socket': one thread reads data from a 'Socket'
+-- only and the other thread writes data to the 'Socket' only.
 -----------------------------------------------------------------------------
 
 #include "HsNet.h"
@@ -114,6 +120,7 @@
     , accept
     -- ** Closing
     , close
+    , close'
     , shutdown
     , ShutdownCmd(..)
     -- * Socket options
@@ -623,7 +630,8 @@
        -> IO (Socket,                   -- Readable Socket
               SockAddr)                 -- Peer details
 
-accept sock@(MkSocket s family stype protocol status) = withMVar status $ \currentStatus -> do
+accept sock@(MkSocket s family stype protocol status) = do
+ currentStatus <- readMVar status
  if not $ isAcceptable family stype currentStatus
    then
      ioError $ userError $
@@ -1295,17 +1303,40 @@
 
 -- -----------------------------------------------------------------------------
 
--- | Close the socket. Sending data to or receiving data from closed socket
--- may lead to undefined behaviour.
+-- | Close the socket. This function does not throw exceptions even if
+--   the underlying system call returns errors.
+--
+--   Sending data to or receiving data from closed socket
+--   may lead to undefined behaviour.
+--
+--   If multiple threads use the same socket and one uses 'fdSocket' and
+--   the other use 'close', unexpected behavior may happen.
+--   For more information, please refer to the documentation of 'fdSocket'.
 close :: Socket -> IO ()
-close (MkSocket s _ _ _ socketStatus) = do
- modifyMVar_ socketStatus $ \ status ->
+close (MkSocket s _ _ _ socketStatus) = modifyMVar_ socketStatus $ \ status ->
    case status of
-     ConvertedToHandle ->
-         ioError (userError ("close: converted to a Handle, use hClose instead"))
-     Closed ->
-         return status
-     _ -> closeFdWith (closeFd . fromIntegral) (fromIntegral s) >> return Closed
+     ConvertedToHandle -> return ConvertedToHandle
+     Closed            -> return Closed
+     _                 -> do
+         -- closeFdWith avoids the deadlock of IO manager.
+         closeFdWith (void . c_close . fromIntegral) (fromIntegral s)
+         return Closed
+
+-- | Close the socket. This function throws exceptions if
+--   the underlying system call returns errors.
+--
+--   Sending data to or receiving data from closed socket
+--   may lead to undefined behaviour.
+close' :: Socket -> IO ()
+close' (MkSocket s _ _ _ socketStatus) = modifyMVar_ socketStatus $ \ status ->
+   case status of
+     ConvertedToHandle -> ioError (userError ("close: converted to a Handle, use hClose instead"))
+     Closed            -> return Closed
+     _                 -> do
+         -- closeFdWith avoids the deadlock of IO manager.
+         -- closeFd throws exceptions.
+         closeFdWith (closeFd . fromIntegral) (fromIntegral s)
+         return Closed
 
 -- -----------------------------------------------------------------------------
 
diff --git a/Network/Socket/ByteString/Lazy/Posix.hs b/Network/Socket/ByteString/Lazy/Posix.hs
--- a/Network/Socket/ByteString/Lazy/Posix.hs
+++ b/Network/Socket/ByteString/Lazy/Posix.hs
@@ -1,5 +1,7 @@
 {-# OPTIONS_GHC -fno-warn-warnings-deprecations #-}
 {-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE OverloadedStrings #-}
+
 module Network.Socket.ByteString.Lazy.Posix
     (
     -- * Send data to a socket
@@ -50,6 +52,7 @@
 sendAll :: Socket      -- ^ Connected socket
         -> ByteString  -- ^ Data to send
         -> IO ()
+sendAll _    "" = return ()
 sendAll sock bs = do
   sent <- send sock bs
   waitWhen0 (fromIntegral sent) sock
diff --git a/Network/Socket/ByteString/Lazy/Windows.hs b/Network/Socket/ByteString/Lazy/Windows.hs
--- a/Network/Socket/ByteString/Lazy/Windows.hs
+++ b/Network/Socket/ByteString/Lazy/Windows.hs
@@ -1,4 +1,6 @@
 {-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE OverloadedStrings #-}
+
 module Network.Socket.ByteString.Lazy.Windows
     (
     -- * Send data to a socket
@@ -31,6 +33,7 @@
 sendAll :: Socket        -- ^ Connected socket
         -> L.ByteString  -- ^ Data to send
         -> IO ()
+sendAll _    "" = return ()
 sendAll sock bs = do
   sent <- send sock bs
   waitWhen0 (fromIntegral sent) sock
diff --git a/Network/Socket/Types.hsc b/Network/Socket/Types.hsc
--- a/Network/Socket/Types.hsc
+++ b/Network/Socket/Types.hsc
@@ -87,6 +87,21 @@
 {-# DEPRECATED MkSocket "'MkSocket' will not be available in version 3.0.0.0 or later. Use fdSocket instead" #-}
 
 -- | Obtaining the file descriptor from a socket.
+--
+--   If a 'Socket' is shared with multiple threads and
+--   one uses 'fdSocket', unexpected issues may happen.
+--   Consider the following scenario:
+--
+--   1) Thread A acquires a 'Fd' from 'Socket' by 'fdSocket'.
+--
+--   2) Thread B close the 'Socket'.
+--
+--   3) Thread C opens a new 'Socket'. Unfortunately it gets the same 'Fd'
+--      number which thread A is holding.
+--
+--   In this case, it is safer for Thread A to clone 'Fd' by
+--   'System.Posix.IO.dup'. But this would still suffer from
+--   a rase condition between 'fdSocket' and 'close'.
 fdSocket :: Socket -> CInt
 fdSocket (MkSocket fd _ _ _ _) = fd
 
diff --git a/configure.ac b/configure.ac
--- a/configure.ac
+++ b/configure.ac
@@ -1,4 +1,4 @@
-AC_INIT([Haskell network package], [2.7.0.1], [libraries@haskell.org], [network])
+AC_INIT([Haskell network package], [2.7.0.2], [libraries@haskell.org], [network])
 
 ac_includes_default="$ac_includes_default
 #ifdef HAVE_SYS_SOCKET_H
diff --git a/network.cabal b/network.cabal
--- a/network.cabal
+++ b/network.cabal
@@ -1,5 +1,5 @@
 name:           network
-version:        2.7.0.1
+version:        2.7.0.2
 license:        BSD3
 license-file:   LICENSE
 maintainer:     Kazu Yamamoto, Evan Borden
@@ -69,8 +69,8 @@
   extensions:
     CPP, DeriveDataTypeable, ForeignFunctionInterface, TypeSynonymInstances
   include-dirs: include
-  includes: HsNet.h
-  install-includes: HsNet.h
+  includes: HsNet.h HsNetDef.h
+  install-includes: HsNet.h HsNetDef.h
   c-sources: cbits/HsNet.c
   ghc-options: -Wall -fwarn-tabs
 
diff --git a/tests/SimpleSpec.hs b/tests/SimpleSpec.hs
--- a/tests/SimpleSpec.hs
+++ b/tests/SimpleSpec.hs
@@ -11,8 +11,10 @@
 import Data.ByteString (ByteString)
 import qualified Data.ByteString as S
 import qualified Data.ByteString.Char8 as C
+import qualified Data.ByteString.Lazy as L
 import Network.Socket hiding (send, sendTo, recv, recvFrom)
 import Network.Socket.ByteString
+import qualified Network.Socket.ByteString.Lazy as Lazy
 import System.Directory
 import System.Timeout (timeout)
 
@@ -33,6 +35,12 @@
         it "works well" $ do
             let server sock = recv sock 1024 `shouldReturn` testMsg
                 client sock = sendAll sock testMsg
+            tcpTest client server
+
+    describe "Lazy.sendAll" $ do
+        it "works well" $ do
+            let server sock = recv sock 1024 `shouldReturn` testMsg
+                client sock = Lazy.sendAll sock $ L.fromChunks [testMsg]
             tcpTest client server
 
     describe "sendTo" $ do