Bug fix from Vladimir Oleynic via Paul Fox for:

echo "+bond0" > /sys/class/net/bonding_masters
while true; do
  echo hello
done

shell/ash.c

@@ -3469,6 +3469,7 @@ evalbltin(const struct builtincmd *cmd, int argc, char **argv) {
 	flushall();
 cmddone:
 	exitstatus |= ferror(stdout);
+	clearerr(stdout);
 	commandname = savecmdname;
 	exsig = 0;
 	handler = savehandler;