diff --git a/Control/Concurrent/ReadWriteLock.hs b/Control/Concurrent/ReadWriteLock.hs
--- a/Control/Concurrent/ReadWriteLock.hs
+++ b/Control/Concurrent/ReadWriteLock.hs
@@ -73,9 +73,9 @@
 
 -- from base:
 import Control.Applicative     ( liftA2, liftA3 )
-import Control.Concurrent.MVar ( MVar, newMVar, takeMVar, putMVar, swapMVar )
+import Control.Concurrent.MVar ( MVar, newMVar, takeMVar, putMVar )
 import Control.Exception       ( bracket_, onException )
-import Control.Monad           ( return, return, (>>), when )
+import Control.Monad           ( return, (>>) )
 import Data.Bool               ( Bool(False, True) )
 import Data.Eq                 ( Eq, (==) )
 import Data.Function           ( ($), on )
@@ -97,9 +97,9 @@
 -- from concurrent-extra (this package):
 import           Control.Concurrent.Lock ( Lock )
 import qualified Control.Concurrent.Lock as Lock
-    ( new, newAcquired, acquire, tryAcquire, release, wait )
+    ( new, newAcquired, acquire, release, wait )
 
-import Utils ( void, mask, mask_ )
+import Utils ( mask, mask_ )
 
 
 -------------------------------------------------------------------------------
@@ -277,8 +277,8 @@
                                   Lock.wait readLock
                                   acqWrite
                       Write  → do putMVar state st
-                                  Lock.acquire writeLock
-                                  void $ swapMVar state Write
+                                  Lock.wait writeLock
+                                  acqWrite
 
 {-|
 Try to acquire the write lock; non blocking.
@@ -293,12 +293,8 @@
     Free   → do Lock.acquire writeLock
                 putMVar state Write
                 return True
-    Read _ → do putMVar state st
+    _      → do putMVar state st
                 return False
-    Write  → do putMVar state st
-                b ← Lock.tryAcquire writeLock
-                when b $ void $ swapMVar state Write
-                return b
 
 {-|
 Release the write lock.
diff --git a/Control/Concurrent/ReadWriteLock/Test.hs b/Control/Concurrent/ReadWriteLock/Test.hs
--- a/Control/Concurrent/ReadWriteLock/Test.hs
+++ b/Control/Concurrent/ReadWriteLock/Test.hs
@@ -8,9 +8,12 @@
 -------------------------------------------------------------------------------
 
 -- from base:
-import Control.Monad      ( (>>) )
+import Control.Monad      ( (>>), (>>=), replicateM_ )
 import Control.Concurrent ( forkIO, threadDelay )
 import Data.Function      ( ($) )
+import Data.Foldable      ( sequenceA_ )
+import Data.List          ( map, replicate, (++) )
+import System.Random      ( randomRIO )
 
 #if __GLASGOW_HASKELL__ < 700
 import Prelude            ( fromInteger )
@@ -20,9 +23,12 @@
 -- from base-unicode-symbols:
 import Prelude.Unicode    ( (⋅) )
 
+-- from async:
+import Control.Concurrent.Async ( Concurrently(Concurrently), runConcurrently )
+
 -- from concurrent-extra:
 import qualified Control.Concurrent.ReadWriteLock as RWLock
-    ( new, acquireWrite, acquireRead, releaseWrite, releaseRead  )
+    ( new, acquireWrite, acquireRead, releaseWrite, releaseRead, withRead, withWrite  )
 
 import TestUtils ( within, a_moment )
 
@@ -45,6 +51,7 @@
 tests ∷ [Test]
 tests = [ testCase "test1" test1
         , testCase "test2" test2
+        , testCase "stressTest" stressTest
         ]
 
 test1 ∷ Assertion
@@ -90,3 +97,20 @@
           -- The read-write-lock should now be in the "Free" state so the
           -- following shouldn't deadlock:
           RWLock.acquireRead rwl
+
+stressTest :: Assertion
+stressTest = assert $ within (500 ⋅ a_moment) $ do
+  lock <- RWLock.new
+
+  let randomDelay hi = randomRIO (0, hi) >>= threadDelay
+
+      reader = replicateM_ 500 $ do
+        randomDelay 100
+        RWLock.withRead lock $ randomDelay 10
+
+      writer = replicateM_ 500 $ do
+        randomDelay 100
+        RWLock.withWrite lock $ randomDelay 10
+
+  runConcurrently $ sequenceA_ $ map Concurrently $
+    replicate 10 reader ++ replicate 10 writer
diff --git a/concurrent-extra.cabal b/concurrent-extra.cabal
--- a/concurrent-extra.cabal
+++ b/concurrent-extra.cabal
@@ -1,5 +1,5 @@
 name:          concurrent-extra
-version:       0.7.0.7
+version:       0.7.0.8
 cabal-version: >= 1.8
 build-type:    Custom
 stability:     experimental
@@ -85,7 +85,9 @@
                , stm                  >= 2.1.2.1 && < 2.5
                , unbounded-delays     >= 0.1     && < 0.2
                , HUnit                >= 1.2.2   && < 1.3
+               , random               >= 1.0     && < 1.1
                , test-framework       >= 0.2.4   && < 0.9
                , test-framework-hunit >= 0.2.4   && < 0.4
+               , async                >= 2.0     && < 2.1
 
 -------------------------------------------------------------------------------