patch "n_tty: Fix stale echo output" added to tty tree

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This is a note to let you know that I've just added the patch titled

    n_tty: Fix stale echo output

to my tty git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-next branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will also be merged in the next major kernel release
during the merge window.

If you have any questions about this process, please let me know.


>From e2613be5093d04e6589924d36a1e363eef3c87c7 Mon Sep 17 00:00:00 2001
From: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
Date: Tue, 11 Feb 2014 16:34:55 -0500
Subject: n_tty: Fix stale echo output

When echoes cannot be flushed to output (usually because the tty
has no more write room) and L_ECHO is subsequently turned off, then
when L_ECHO is turned back on, stale echoes are output.

Output completed echoes regardless of the L_ECHO setting:
  1. before normal writes to that tty
  2. if the tty was stopped by soft flow control and is being
     restarted

Reported-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 3.13.x
Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/tty/n_tty.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 2747a3b20a50..d15624c1b751 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -817,8 +817,7 @@ static void process_echoes(struct tty_struct *tty)
 	struct n_tty_data *ldata = tty->disc_data;
 	size_t echoed;
 
-	if ((!L_ECHO(tty) && !L_ECHONL(tty)) ||
-	    ldata->echo_mark == ldata->echo_tail)
+	if (ldata->echo_mark == ldata->echo_tail)
 		return;
 
 	mutex_lock(&ldata->output_lock);
@@ -1244,7 +1243,8 @@ n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c)
 	if (L_ECHO(tty)) {
 		echo_char(c, tty);
 		commit_echoes(tty);
-	}
+	} else
+		process_echoes(tty);
 	isig(signal, tty);
 	return;
 }
@@ -1274,7 +1274,7 @@ n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
 	if (I_IXON(tty)) {
 		if (c == START_CHAR(tty)) {
 			start_tty(tty);
-			commit_echoes(tty);
+			process_echoes(tty);
 			return 0;
 		}
 		if (c == STOP_CHAR(tty)) {
@@ -1820,8 +1820,10 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
 	 * Fix tty hang when I_IXON(tty) is cleared, but the tty
 	 * been stopped by STOP_CHAR(tty) before it.
 	 */
-	if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped)
+	if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) {
 		start_tty(tty);
+		process_echoes(tty);
+	}
 
 	/* The termios change make the tty ready for I/O */
 	if (waitqueue_active(&tty->write_wait))
-- 
1.8.5.1.163.gd7aced9


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