diff -r 805edf16e8e0 -r 94ba29934f00 mercurial/sshpeer.py
--- a/mercurial/sshpeer.py	Sun Feb 04 11:37:19 2018 -0800
+++ b/mercurial/sshpeer.py	Sun Feb 04 11:40:13 2018 -0800
@@ -173,8 +173,7 @@
     # End of _basewirecommands interface.
 
     def _validaterepo(self, sshcmd, args, remotecmd, sshenv=None):
-        # cleanup up previous run
-        self._cleanup()
+        assert self._pipei is None
 
         cmd = '%s %s %s' % (sshcmd, args,
             util.shellquote("%s -R %s serve --stdio" %