Really fix deadlock causing race condition

pipe_io_server/pipe_writer_thread.py

@@ -39,13 +39,12 @@ class PipeWriterThread(Thread):
         return open(self._pipe_path, 'wb')
 
     def stop(self):
-        self._unblock()
+        while self.is_alive():
+            self._unblock()
         self.join()
 
     def _unblock(self):
-        while True:
-            with suppress(OSError):
-                fd = osopen(self._pipe_path, O_RDONLY | O_NONBLOCK)
-                self._write_queue.push_front(None)
-                close(fd)
-                break
+        with suppress(OSError):
+            fd = osopen(self._pipe_path, O_RDONLY | O_NONBLOCK)
+            self._write_queue.push_front(None)
+            close(fd)