n_tty: Fix missing newline echo

When L_ECHONL is on, newlines are echoed regardless of the L_ECHO
state; if set, ensure accumulated echoes are flushed before finishing
the current input processing and before more output.

Cc: <stable@vger.kernel.org> # 3.12.x
Reported-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com
Tested-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 0f74945af624..268b62768f2b 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -810,7 +810,8 @@ static void process_echoes(struct tty_struct *tty)
         struct n_tty_data *ldata = tty->disc_data;
         size_t echoed;
 
-        if (!L_ECHO(tty) || ldata->echo_commit == ldata->echo_tail)
+        if ((!L_ECHO(tty) && !L_ECHONL(tty)) ||
+            ldata->echo_commit == ldata->echo_tail)
                 return;
 
         mutex_lock(&ldata->output_lock);
@@ -825,7 +826,8 @@ static void flush_echoes(struct tty_struct *tty)
 {
         struct n_tty_data *ldata = tty->disc_data;
 
-        if (!L_ECHO(tty) || ldata->echo_commit == ldata->echo_head)
+        if ((!L_ECHO(tty) && !L_ECHONL(tty)) ||
+            ldata->echo_commit == ldata->echo_head)
                 return;
 
         mutex_lock(&ldata->output_lock);