From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756090Ab0LHP65 (ORCPT ); Wed, 8 Dec 2010 10:58:57 -0500 Received: from cantor2.suse.de ([195.135.220.15]:48748 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756046Ab0LHP64 (ORCPT ); Wed, 8 Dec 2010 10:58:56 -0500 Date: Wed, 8 Dec 2010 07:50:43 -0800 From: Greg KH To: Jiri Slaby Cc: linux-kernel@vger.kernel.org, stable@kernel.org, stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Alan Cox Subject: Re: [043/127] TTY: ldisc, fix open flag handling Message-ID: <20101208155043.GA10121@suse.de> References: <20101208004428.612566004@clark.site> <4CFF24AE.1030104@suse.cz> <20101208150209.GA5144@suse.de> <4CFF9FA6.70708@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4CFF9FA6.70708@suse.cz> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 08, 2010 at 04:09:26PM +0100, Jiri Slaby wrote: > On 12/08/2010 04:02 PM, Greg KH wrote: > > On Wed, Dec 08, 2010 at 07:24:46AM +0100, Jiri Slaby wrote: > >> On 12/08/2010 01:43 AM, Greg KH wrote: > >>> 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; > >> > >> Whoops, this should write return ret; (with int ret = 0;) > >> > >> Do you want me to send the patch against rebased on .32? > > > > No, send it based on Linus's tree as it's wrong there, right? Then it > > will move through to the stable kernels. > > Nope, in 2.6.36 and newer it looks differently, only the .32 backport is > broken. Ick, ok, sorry about that. Yes, can you just send me a tiny patch that I can merge with the .32 patch to resolve this? thanks, greg k-h