diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 79e62e8e7..d5ffcecf8 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,9 @@
+2005-09-06  Corinna Vinschen  <corinna@vinschen.de>
+
+	* thread.h: Revert patch from 2005-09-05.
+	* thread.cc (pthread_mutex::can_be_unlocked): Return true also if
+	mutex is owned by MUTEX_OWNER_ANONYMOUS.
+
 2005-09-05  Christopher Faylor  <cgf@timesys.com>
 
 	* cygheap.cc (cygheap_init): Eliminate debugging #if.
diff --git a/winsup/cygwin/thread.cc b/winsup/cygwin/thread.cc
index 9f4899e91..11d60fc0e 100644
--- a/winsup/cygwin/thread.cc
+++ b/winsup/cygwin/thread.cc
@@ -212,10 +212,11 @@ pthread_mutex::can_be_unlocked (pthread_mutex_t const *mutex)
 
   if (!is_good_object (mutex))
     return false;
-  /*
-   * Check if the mutex is owned by the current thread and can be unlocked
-   */
-  return ((*mutex)->recursion_counter == 1 && pthread::equal ((*mutex)->owner, self));
+  /* Check if the mutex is owned by the current thread and can be unlocked.
+   * Also check for the ANONYMOUS owner to cover NORMAL mutexes as well. */
+  return ((*mutex)->recursion_counter == 1
+	  && ((*mutex)->owner == MUTEX_OWNER_ANONYMOUS
+	      || pthread::equal ((*mutex)->owner, self)));
 }
 
 inline bool
diff --git a/winsup/cygwin/thread.h b/winsup/cygwin/thread.h
index f8ab9da8b..c15ded478 100644
--- a/winsup/cygwin/thread.h
+++ b/winsup/cygwin/thread.h
@@ -301,21 +301,27 @@ public:
   int type;
   int pshared;
 
+  pthread_t get_pthread_self () const
+  {
+    return PTHREAD_MUTEX_NORMAL == type ? MUTEX_OWNER_ANONYMOUS :
+      ::pthread_self ();
+  }
+
   int lock ()
   {
-    return _lock (::pthread_self ());
+    return _lock (get_pthread_self ());
   }
   int trylock ()
   {
-    return _trylock (::pthread_self ());
+    return _trylock (get_pthread_self ());
   }
   int unlock ()
   {
-    return _unlock (::pthread_self ());
+    return _unlock (get_pthread_self ());
   }
   int destroy ()
   {
-    return _destroy (::pthread_self ());
+    return _destroy (get_pthread_self ());
   }
 
   void set_owner (pthread_t self)