diff -r be930f16a52a -r e461230cc95b mercurial/sshpeer.py
--- a/mercurial/sshpeer.py	Sat May 30 23:55:24 2015 -0700
+++ b/mercurial/sshpeer.py	Sun May 31 00:00:36 2015 -0700
@@ -89,6 +89,8 @@
         # to clean up correctly later
         self.pipeo, self.pipei, self.pipee, self.subprocess = util.popen4(cmd)
 
+        self.pipei = util.bufferedinputpipe(self.pipei)
+
         # skip any noise generated by remote shell
         self._callstream("hello")
         r = self._callstream("between", pairs=("%s-%s" % ("0"*40, "0"*40)))