From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758029Ab0LHCNI (ORCPT ); Tue, 7 Dec 2010 21:13:08 -0500 Received: from kroah.org ([198.145.64.141]:46068 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756039Ab0LHArI (ORCPT ); Tue, 7 Dec 2010 19:47:08 -0500 X-Mailbox-Line: From gregkh@clark.site Tue Dec 7 16:44:28 2010 Message-Id: <20101208004428.612566004@clark.site> User-Agent: quilt/0.48-11.2 Date: Tue, 07 Dec 2010 16:43:49 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Jiri Slaby , Alan Cox Subject: [043/127] TTY: ldisc, fix open flag handling In-Reply-To: <20101208004456.GA23578@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-stable review patch. If anyone has any objections, please let us know. ------------------ From: Jiri Slaby commit 7f90cfc505d613f4faf096e0d84ffe99208057d9 upstream. When a concrete ldisc open fails in tty_ldisc_open, we forget to clear TTY_LDISC_OPEN. This causes a false warning on the next ldisc open: WARNING: at drivers/char/tty_ldisc.c:445 tty_ldisc_open+0x26/0x38() Hardware name: System Product Name Modules linked in: ... Pid: 5251, comm: a.out Tainted: G W 2.6.32-5-686 #1 Call Trace: [] ? warn_slowpath_common+0x5e/0x8a [] ? warn_slowpath_null+0xa/0xc [] ? tty_ldisc_open+0x26/0x38 [] ? tty_set_ldisc+0x218/0x304 ... So clear the bit when failing... Introduced in c65c9bc3efa (tty: rewrite the ldisc locking) back in 2.6.31-rc1. Signed-off-by: Jiri Slaby Cc: Alan Cox Reported-by: Sergey Lapin Tested-by: Sergey Lapin Signed-off-by: Greg Kroah-Hartman --- drivers/char/tty_ldisc.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/drivers/char/tty_ldisc.c +++ b/drivers/char/tty_ldisc.c @@ -444,9 +444,14 @@ static void tty_set_termios_ldisc(struct static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld) { + int ret; + WARN_ON(test_and_set_bit(TTY_LDISC_OPEN, &tty->flags)); - if (ld->ops->open) - return ld->ops->open(tty); + if (ld->ops->open) { + ret = ld->ops->open(tty); + if (ret) + clear_bit(TTY_LDISC_OPEN, &tty->flags); + } return 0; }