From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932503Ab2EGVEZ (ORCPT ); Mon, 7 May 2012 17:04:25 -0400 Received: from mail-wi0-f178.google.com ([209.85.212.178]:48590 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757762Ab2EGVEX (ORCPT ); Mon, 7 May 2012 17:04:23 -0400 Message-ID: <4FA838D2.9000908@suse.cz> Date: Mon, 07 May 2012 23:04:18 +0200 From: Jiri Slaby User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120428 Thunderbird/14.0a2 MIME-Version: 1.0 To: Sasha Levin CC: Alan Cox , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Jiri Slaby Subject: Re: [PATCH 3/3] tty_lock: Localise the lock References: <20120503212151.568.91854.stgit@bob.linux.org.uk> <20120503212219.568.15653.stgit@bob.linux.org.uk> <20120507171126.5beddc27@pyramind.ukuu.org.uk> <1336408208.3638.15.camel@lappy> <20120507174240.4209c5cb@pyramind.ukuu.org.uk> In-Reply-To: X-Enigmail-Version: 1.5pre 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 05/07/2012 07:00 PM, Sasha Levin wrote: >> So whatever your trace is showing, that's not the bug. Something more >> complicated would appear to be afoot. > > Oddly enough, tty != tty->link, but the lockdep warning triggers. > > Any idea why it might happen? I think so, both locks are the same lockdep class. So lockdep thinks it is the same lock. However this is a false positive. I guess we need mutex_lock_nested... regards, -- js suse labs