From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757093Ab3FDOYN (ORCPT ); Tue, 4 Jun 2013 10:24:13 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:46705 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755381Ab3FDOHx (ORCPT ); Tue, 4 Jun 2013 10:07:53 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Wang YanQing , Greg Kroah-Hartman , Luis Henriques Subject: [PATCH 19/70] TTY: Fix tty miss restart after we turn off flow-control Date: Tue, 4 Jun 2013 15:06:35 +0100 Message-Id: <1370354846-14213-20-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1370354846-14213-1-git-send-email-luis.henriques@canonical.com> References: <1370354846-14213-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.5.7.14 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Wang YanQing commit dab73b4eb9ef924a2b90dab84e539076d82b256f upstream. 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 Signed-off-by: Greg Kroah-Hartman [ luis: adjust context ] Signed-off-by: Luis Henriques --- drivers/tty/n_tty.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index 26f0d0e..72d3ff8 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -1529,6 +1529,14 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) tty->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); -- 1.8.1.2