diff --git a/supervisor/supervisord.py b/supervisor/supervisord.py
index 0a4f3e697..2265db9c7 100755
--- a/supervisor/supervisord.py
+++ b/supervisor/supervisord.py
@@ -222,6 +222,14 @@ def runforever(self):
                         raise
                     except:
                         combined_map[fd].handle_error()
+                else:
+                    # if the fd is not in combined_map, we should unregister it. otherwise,
+                    # it will be polled every time, which may cause 100% cpu usage
+                    self.options.logger.warn('unexpected read event from fd %r' % fd)
+                    try:
+                        self.options.poller.unregister_readable(fd)
+                    except:
+                        pass
 
             for fd in w:
                 if fd in combined_map:
@@ -237,6 +245,12 @@ def runforever(self):
                         raise
                     except:
                         combined_map[fd].handle_error()
+                else:
+                    self.options.logger.warn('unexpected write event from fd %r' % fd)
+                    try:
+                        self.options.poller.unregister_writable(fd)
+                    except:
+                        pass
 
             for group in pgroups:
                 group.transition()