diff -urp src.old/winsup/cygwin/thread.cc src/winsup/cygwin/thread.cc
--- src.old/winsup/cygwin/thread.cc	Thu Apr 25 10:11:30 2002
+++ src/winsup/cygwin/thread.cc	Thu Apr 25 10:49:22 2002
@@ -346,7 +346,8 @@ MTinterface::fixup_after_fork (void)
 }
 
 pthread::pthread ():verifyable_object (PTHREAD_MAGIC), win32_obj_id (0),
-                    cancelstate (0), canceltype (0), cleanup_handlers(NULL), joiner(NULL)
+                    cancelstate (0), canceltype (0), mutex(NULL),
+                    cleanup_handlers(NULL), joiner(NULL)
 {
 }
 
@@ -354,6 +355,7 @@ pthread::~pthread ()
 {
   if (win32_obj_id)
     CloseHandle (win32_obj_id);
+  __pthread_mutex_destroy(&mutex);
 }
 
 
@@ -361,6 +363,8 @@ void
 pthread::create (void *(*func) (void *), pthread_attr *newattr,
 		 void *threadarg)
 {
+  int temperr;
+
   /*already running ? */
   if (win32_obj_id)
     return;
@@ -375,6 +379,14 @@ pthread::create (void *(*func) (void *),
   function = func;
   arg = threadarg;
 
+  if ((temperr = __pthread_mutex_init (&mutex, NULL)))
+    {
+      system_printf ("couldn't init mutex, this %p errno %d", this, temperr);
+      /*we need the mutex for correct behaviour */
+      magic = 0;
+      return;
+    }
+
   win32_obj_id = ::CreateThread (&sec_none_nih, attr.stacksize,
 				(LPTHREAD_START_ROUTINE) thread_init_wrapper,
 				this, CREATE_SUSPENDED, &thread_id);
@@ -908,9 +920,11 @@ thread_init_wrapper (void *_arg)
   /*the OS doesn't check this for <= 64 Tls entries (pre win2k) */
   TlsSetValue (MT_INTERFACE->thread_self_dwTlsIndex, thread);
 
+  __pthread_mutex_lock(&thread->mutex);
   // if thread is detached force cleanup on exit
   if (thread->attr.joinable == PTHREAD_CREATE_DETACHED && thread->joiner == NULL)
     thread->joiner = __pthread_self();
+  __pthread_mutex_unlock(&thread->mutex);
 
 #ifdef _CYG_THREAD_FAILSAFE
   if (_REENT == _impure_ptr)
@@ -1225,8 +1239,13 @@ __pthread_cleanup_push (__pthread_cleanu
 {
   pthread_t thread = __pthread_self ();
 
+  // cleanup_push is not async cancel safe
+  __pthread_mutex_lock(&thread->mutex);
+
   handler->next = thread->cleanup_handlers;
   thread->cleanup_handlers = handler;
+
+  __pthread_mutex_unlock(&thread->mutex);
 }
 
 void
@@ -1537,11 +1556,15 @@ __pthread_exit (void *value_ptr)
 
   MT_INTERFACE->destructors.IterateNull ();
 
-  // cleanup if thread is in detached state and not joined
+  __pthread_mutex_lock(&thread->mutex);
   if( __pthread_equal(&thread->joiner, &thread ) )
+    // cleanup if thread is in detached state and not joined
     delete thread;
   else
-    thread->return_ptr = value_ptr;
+    {
+      __pthread_mutex_unlock(&thread->mutex);
+      thread->return_ptr = value_ptr;
+    }
 
   if (InterlockedDecrement (&MT_INTERFACE->threadcount) == 0)
     exit (0);
@@ -1558,24 +1581,27 @@ __pthread_join (pthread_t *thread, void 
   if (verifyable_object_isvalid (thread, PTHREAD_MAGIC) != VALID_OBJECT)
     return ESRCH;
 
-  if ((*thread)->attr.joinable == PTHREAD_CREATE_DETACHED)
+  if( __pthread_equal(thread, &joiner ) )
     {
       if (return_val)
         *return_val = NULL;
-      return EINVAL;
+      return EDEADLK;
     }
 
-  else if( __pthread_equal(thread, &joiner ) )
+  __pthread_mutex_lock(&(*thread)->mutex);
+  if ((*thread)->attr.joinable == PTHREAD_CREATE_DETACHED)
     {
+       __pthread_mutex_unlock(&(*thread)->mutex);
       if (return_val)
         *return_val = NULL;
-      return EDEADLK;
+      return EINVAL;
     }
 
   else
     {
       (*thread)->joiner = joiner;
       (*thread)->attr.joinable = PTHREAD_CREATE_DETACHED;
+       __pthread_mutex_unlock(&(*thread)->mutex);
       WaitForSingleObject ((*thread)->win32_obj_id, INFINITE);
       if (return_val)
          *return_val = (*thread)->return_ptr;
@@ -1594,14 +1620,23 @@ __pthread_detach (pthread_t *thread)
   if (verifyable_object_isvalid (thread, PTHREAD_MAGIC) != VALID_OBJECT)
     return ESRCH;
 
+  __pthread_mutex_lock(&(*thread)->mutex);
   if ((*thread)->attr.joinable == PTHREAD_CREATE_DETACHED)
     {
+      __pthread_mutex_unlock(&(*thread)->mutex);
       return EINVAL;
     }
 
-  // force cleanup on exit
-  (*thread)->joiner = *thread;
-  (*thread)->attr.joinable = PTHREAD_CREATE_DETACHED;
+  // check if thread is still alive
+  if( WAIT_TIMEOUT == WaitForSingleObject ((*thread)->win32_obj_id, 0) )
+    {
+      (*thread)->joiner = *thread;
+      (*thread)->attr.joinable = PTHREAD_CREATE_DETACHED;
+      __pthread_mutex_unlock(&(*thread)->mutex);
+    }
+  else
+    // thread has already terminated
+    delete (*thread);
 
   return 0;
 }
diff -urp src.old/winsup/cygwin/thread.h src/winsup/cygwin/thread.h
--- src.old/winsup/cygwin/thread.h	Thu Apr 25 10:11:30 2002
+++ src/winsup/cygwin/thread.h	Thu Apr 25 09:15:17 2002
@@ -239,6 +239,7 @@ public:
   void *return_ptr;
   bool suspended;
   int cancelstate, canceltype;
+  pthread_mutex *mutex;
   __pthread_cleanup_handler *cleanup_handlers;
   pthread_t joiner;
   // int joinable;