The following patch was not accepted upstream, see:
http://sourceware.org/bugzilla/show_bug.cgi?id=5379

It needs rework.

Index: sunrpc/clnt_udp.c
===================================================================
--- sunrpc/clnt_udp.c.orig
+++ sunrpc/clnt_udp.c
@@ -301,6 +301,7 @@ clntudp_call (cl, proc, xargs, argsp, xr
   XDR *xdrs;
   int outlen = 0;
   int inlen;
+  int pollresult;
   socklen_t fromlen;
   struct pollfd fd;
   int milliseconds = (cu->cu_wait.tv_sec * 1000) +
@@ -371,37 +372,36 @@ send_again:
   anyup = 0;
   for (;;)
     {
-      switch (__poll (&fd, 1, milliseconds))
+      switch (pollresult = __poll (&fd, 1, milliseconds))
 	{
-
 	case 0:
-	  if (anyup == 0)
-	    {
-	      anyup = is_network_up (cu->cu_sock);
-	      if (!anyup)
-		return (cu->cu_error.re_status = RPC_CANTRECV);
-	    }
-
-	  time_waited.tv_sec += cu->cu_wait.tv_sec;
-	  time_waited.tv_usec += cu->cu_wait.tv_usec;
-	  while (time_waited.tv_usec >= 1000000)
-	    {
-	      time_waited.tv_sec++;
-	      time_waited.tv_usec -= 1000000;
-	    }
-	  if ((time_waited.tv_sec < timeout.tv_sec) ||
-	      ((time_waited.tv_sec == timeout.tv_sec) &&
-	       (time_waited.tv_usec < timeout.tv_usec)))
-	    goto send_again;
-	  return (cu->cu_error.re_status = RPC_TIMEDOUT);
-
-	  /*
-	   * buggy in other cases because time_waited is not being
-	   * updated.
-	   */
 	case -1:
-	  if (errno == EINTR)
-	    continue;
+	  if (pollresult == 0 || errno == EINTR) {
+	    if (anyup == 0)
+	      {
+		anyup = is_network_up (cu->cu_sock);
+		if (!anyup)
+		  return (cu->cu_error.re_status = RPC_CANTRECV);
+	      }
+
+	    time_waited.tv_sec += cu->cu_wait.tv_sec;
+	    time_waited.tv_usec += cu->cu_wait.tv_usec;
+	    while (time_waited.tv_usec >= 1000000)
+	      {
+		time_waited.tv_sec++;
+		time_waited.tv_usec -= 1000000;
+	      }
+	    if ((time_waited.tv_sec < timeout.tv_sec) ||
+		((time_waited.tv_sec == timeout.tv_sec) &&
+		 (time_waited.tv_usec < timeout.tv_usec)))
+	      if (pollresult == 0)
+		goto send_again;
+	      else
+		continue;
+	    return (cu->cu_error.re_status = RPC_TIMEDOUT);
+	  }
+
+	  /* errno != EINTR */
 	  cu->cu_error.re_errno = errno;
 	  return (cu->cu_error.re_status = RPC_CANTRECV);
 	}