Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932222AbZLMBP1 (ORCPT ); Sat, 12 Dec 2009 20:15:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932188AbZLMBPU (ORCPT ); Sat, 12 Dec 2009 20:15:20 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:49875 "HELO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1756577AbZLMBPS (ORCPT ); Sat, 12 Dec 2009 20:15:18 -0500 Date: Sat, 12 Dec 2009 09:16:43 -0800 (PST) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: Andrew Morton cc: Ingo Molnar , Greg KH , Alan Cox , Thomas Gleixner , Peter Zijlstra , linux-kernel@vger.kernel.org Subject: Re: [GIT PATCH] TTY patches for 2.6.33-git In-Reply-To: <20091212023603.93768833.akpm@linux-foundation.org> Message-ID: References: <20091211232805.GA10652@kroah.com> <20091212084611.GA28266@elte.hu> <20091212013927.58d386d1.akpm@linux-foundation.org> <20091212101032.GB25286@elte.hu> <20091212023603.93768833.akpm@linux-foundation.org> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1250 Lines: 37 On Sat, 12 Dec 2009, Andrew Morton wrote: > On Sat, 12 Dec 2009 11:10:32 +0100 Ingo Molnar wrote: > > > > > * Andrew Morton wrote: > > > > > Seems to be quite .config-dependent. > > > > My theory is that it's a race and that it's thus timing dependent. TTY > > SMP details get stressed most during a particular point during bootup, > > when all the mingetty's are starting up all at once and race with each > > other. > > > > If you are lucky to not hit the bug then, then the likelyhood is much > > lower later on. > > > > It would be nice if Alan posted his TTY stress-testing code. It could > > potentially make this bug bisectable. > > > > I'm surprised that lockdep didn't notice that ab/ba I thought I saw. > Maybe the do_tty_hangup()->tty_fasync() never happens. The kernel lock cannot have any ABBA deadlocks. If somebody blocks on another lock (after getting the kernel lock), the kernel lock will be dropped. So no ABBA. Linus -- 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/