From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753920AbZLAQBy (ORCPT ); Tue, 1 Dec 2009 11:01:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753890AbZLAQBx (ORCPT ); Tue, 1 Dec 2009 11:01:53 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:45042 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753835AbZLAQBv (ORCPT ); Tue, 1 Dec 2009 11:01:51 -0500 Date: Tue, 1 Dec 2009 17:01:51 +0100 From: Pavel Machek To: Alan Cox Cc: kernel list , linux-bluetooth@vger.kernel.org, Marcel Holtmann Subject: Re: divide by zero in termios when setting bluetooth Message-ID: <20091201160151.GD2262@elf.ucw.cz> References: <20091201151315.GC2262@elf.ucw.cz> <20091201155244.0523d9c9@lxorguk.ukuu.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091201155244.0523d9c9@lxorguk.ukuu.org.uk> X-Warning: Reading this can be dangerous to your mental health. 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 Hi! > > I triggered this by mistake... "W" taint is from the WARN_ON() > > before. > > This ought to fix it > > serial: Fix crash if the minimum rate of the device is > 9600 baud > > From: Alan Cox > > In that situation if the old rate is invalid and the new rate is invalid > and the chip cannot do 9600 baud we report zero, which makes all the > drivers explode. > > Instead force the rate based on min/max > > Signed-off-by: Alan Cox > } > > /* > - * As a last resort, if the quotient is zero, > - * default to 9600 bps > + * As a last resort, if the range cannot be met then clip to > + * the nearest chip supported rate. > */ > - if (!hung_up) > - tty_termios_encode_baud_rate(termios, 9600, 9600); > + if (!hung_up) { > + if (baud <= min) > + tty_termios_encode_baud_rate(termios, > + min + 1, min + 1); > + else > + tty_termios_encode_baud_rate(termios, > + max - 1, max - 1); > + } > } > - > + /* Should never happen */ > + WARN_ON(1); > return 0; Does this mean WARN_ON() on user error? Maybe printk(KERN_ERR) with explanation would be better? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html