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authorWang YanQing <udknight@gmail.com>2013-05-09 14:16:47 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-05-20 12:15:59 -0700
commitdab73b4eb9ef924a2b90dab84e539076d82b256f (patch)
tree50d05c7caa154a4046cce9c1e9890abea37f909c /drivers/tty
parent421b40a6286ee343d77d5e51f5ee6d04d7a2a90f (diff)
downloadlinux-dab73b4eb9ef924a2b90dab84e539076d82b256f.tar.bz2
TTY: Fix tty miss restart after we turn off flow-control
I meet emacs hang in start if I do the operation below: 1: echo 3 > /proc/sys/vm/drop_caches 2: emacs BigFile 3: Press CTRL-S follow 2 immediately Then emacs hang on, CTRL-Q can't resume, the terminal hang on, you can do nothing with this terminal except close it. The reason is before emacs takeover control the tty, we use CTRL-S to XOFF it. Then when emacs takeover the control, it may don't use the flow-control, so emacs hang. This patch fix it. This patch will fix a kind of strange tty relation hang problem, I believe I meet it with vim in ssh, and also see below bug report: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=465823 Signed-off-by: Wang YanQing <udknight@gmail.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/n_tty.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index d655416087b7..6c7fe90ad72d 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -1573,6 +1573,14 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
ldata->real_raw = 0;
}
n_tty_set_room(tty);
+ /*
+ * 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) {
+ start_tty(tty);
+ }
+
/* The termios change make the tty ready for I/O */
wake_up_interruptible(&tty->write_wait);
wake_up_interruptible(&tty->read_wait);