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-linus 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 hopefully also be merged in Linus's tree for the
next -rc kernel release.

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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