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>
---
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 df6dda6..41fe8a0 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))
--
1.8.1.2
--
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