Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S269291AbUIYJTs (ORCPT ); Sat, 25 Sep 2004 05:19:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S269292AbUIYJTr (ORCPT ); Sat, 25 Sep 2004 05:19:47 -0400 Received: from caramon.arm.linux.org.uk ([212.18.232.186]:13833 "EHLO caramon.arm.linux.org.uk") by vger.kernel.org with ESMTP id S269291AbUIYJTo (ORCPT ); Sat, 25 Sep 2004 05:19:44 -0400 Date: Sat, 25 Sep 2004 10:19:37 +0100 From: Russell King To: Paul Fulghum Cc: William Lee Irwin III , James Morris , Andrew Morton , Linux Kernel list , Alan Cox Subject: Re: 2.6.9-rc2-mm3 Message-ID: <20040925101937.A29796@flint.arm.linux.org.uk> Mail-Followup-To: Paul Fulghum , William Lee Irwin III , James Morris , Andrew Morton , Linux Kernel list , Alan Cox References: <20040925013135.GJ9106@holomorphy.com> <1096082711.7111.38.camel@at2.pipehead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <1096082711.7111.38.camel@at2.pipehead.org>; from paulkf@microgate.com on Fri, Sep 24, 2004 at 10:25:11PM -0500 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1178 Lines: 31 On Fri, Sep 24, 2004 at 10:25:11PM -0500, Paul Fulghum wrote: > My suggestion was flawed in that it could > violate POSIX requirements (as Russell pointed out). > > Removing the lock from tty_termios_baud_rate(), tty_io.c > corrects the problem for the path from change_termios() > to tty_termios_baud_rate(), which is causing the deadlock. > > This may not be, and probably is not, > correct for all paths to tty_termios_baud_rate(). I wonder if we should consider adding: WARN_ON(!spin_is_locked(&tty_termios_lock)); in there. However, the one annoying thing about "spin_is_locked" is that, on UP, it defaults to "unlocked" which makes these kinds of checks too noisy. Maybe we need a spin_is_locked() with a bias towards being locked for UP? -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 PCMCIA - http://pcmcia.arm.linux.org.uk/ 2.6 Serial core - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/