From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755583Ab0LHPJe (ORCPT ); Wed, 8 Dec 2010 10:09:34 -0500 Received: from mail-bw0-f45.google.com ([209.85.214.45]:65407 "EHLO mail-bw0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754832Ab0LHPJc (ORCPT ); Wed, 8 Dec 2010 10:09:32 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:x-enigmail-version:content-type :content-transfer-encoding; b=AaDDDyJZlDArxbTKNkObSwl8amrkKPynephzcHO4RdVQ5JPiocc2x5siAhtQLzlbFj Y/x0ii/k9x1WbsazYN8GKIwBqWGGd7MAInWQemOLQ168nKB6uz8X6yv5EN/mjxq1sCJz KJoU36oIUiRUKniMarFXK4pt3SOEdS7z6Tnj8= Message-ID: <4CFF9FA6.70708@suse.cz> Date: Wed, 08 Dec 2010 16:09:26 +0100 From: Jiri Slaby User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; cs-CZ; rv:1.9.2.12) Gecko/20101026 SUSE/3.1.6 Thunderbird/3.1.6 MIME-Version: 1.0 To: Greg KH 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 References: <20101208004428.612566004@clark.site> <4CFF24AE.1030104@suse.cz> <20101208150209.GA5144@suse.de> In-Reply-To: <20101208150209.GA5144@suse.de> X-Enigmail-Version: 1.1.2 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. The .36 backport is OK: --- a/drivers/char/tty_ldisc.c +++ b/drivers/char/tty_ldisc.c @@ -454,6 +454,8 @@ static int tty_ldisc_open(struct tty_str /* BTM here locks versus a hangup event */ WARN_ON(!tty_locked()); ret = ld->ops->open(tty); + if (ret) + clear_bit(TTY_LDISC_OPEN, &tty->flags); return ret; } return 0; thanks, -- js suse labs