Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755904AbXJ1W4S (ORCPT ); Sun, 28 Oct 2007 18:56:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752480AbXJ1W4D (ORCPT ); Sun, 28 Oct 2007 18:56:03 -0400 Received: from palinux.external.hp.com ([192.25.206.14]:38615 "EHLO mail.parisc-linux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752444AbXJ1W4B (ORCPT ); Sun, 28 Oct 2007 18:56:01 -0400 Date: Sun, 28 Oct 2007 16:55:59 -0600 From: Matthew Wilcox To: Alan Cox Cc: Trond Myklebust , "J. Bruce Fields" , Linus Torvalds , linux-kernel@vger.kernel.org, "George G. Davis" , Andrew Morton , linux-fsdevel@vger.kernel.org Subject: Re: [RFC, PATCH] locks: remove posix deadlock detection Message-ID: <20071028225559.GD32359@parisc-linux.org> References: <20071026170750.GC13033@fieldses.org> <20071026224707.GO13033@fieldses.org> <20071028173136.GA16905@fieldses.org> <20071028174321.GB16905@fieldses.org> <20071028182732.GK27248@parisc-linux.org> <20071028184052.49abd092@the-village.bc.nu> <20071028201101.GA32359@parisc-linux.org> <1193608230.7561.11.camel@heimdal.trondhjem.org> <20071028224157.GC32359@parisc-linux.org> <20071028224833.66dc4243@the-village.bc.nu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071028224833.66dc4243@the-village.bc.nu> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1179 Lines: 27 On Sun, Oct 28, 2007 at 10:48:33PM +0000, Alan Cox wrote: > > Bzzt. You get a false deadlock with multiple threads like so: > > > > Thread A of task B takes lock 1 > > Thread C of task D takes lock 2 > > Thread C of task D blocks on lock 1 > > Thread E of task B blocks on lock 2 > > The spec and SYSV certainly ignore threading in this situation and you > know that perfectly well (or did in 2004) The discussion petered out (or that mailing list archive lost articles from the thread) without any kind of resolution, or indeed interest. What is your suggestion for handling this problem? As it is now, the kernel 'detects' deadlock where there is none, which doesn't seem allowed by SuSv3 either. -- Intel are signing my paycheques ... these opinions are still mine "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." - 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/