Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761053AbXFRJpO (ORCPT ); Mon, 18 Jun 2007 05:45:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758809AbXFRJo6 (ORCPT ); Mon, 18 Jun 2007 05:44:58 -0400 Received: from mail-gw2.sa.eol.hu ([212.108.200.109]:41172 "EHLO mail-gw2.sa.eol.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752720AbXFRJo5 (ORCPT ); Mon, 18 Jun 2007 05:44:57 -0400 To: davem@davemloft.net CC: akpm@linux-foundation.org, viro@ftp.linux.org.uk, alan@lxorguk.ukuu.org.uk, netdev@vger.kernel.org, linux-kernel@vger.kernel.org In-reply-to: <20070618.023520.102546505.davem@davemloft.net> (message from David Miller on Mon, 18 Jun 2007 02:35:20 -0700 (PDT)) Subject: Re: [PATCH] fix race in AF_UNIX References: <20070618.021813.105401188.davem@davemloft.net> <20070618.023520.102546505.davem@davemloft.net> Message-Id: From: Miklos Szeredi Date: Mon, 18 Jun 2007 11:44:07 +0200 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1757 Lines: 44 > > > > And is anyone working on a better patch? > > > > > > I have no idea. > > > > > > > Those patches aren't "bad" in the correctness sense. So IMO any one > > > > of them is better, than having that bug in there. > > > > > > You're adding a very serious performance regression, which is > > > about as bad as the bug itself. > > > > No, correctness always trumps performance. > > To a point. There is no black and white in this world. > > > Lost packets on an AF_UNIX socket are _unexceptable_, and this is > > definitely not a theoretical problem. > > A lot of people will consider having all of their AF_UNIX sockets on > their 64 cpu system just stop when garbage collection runs to be > unacceptable as well. Garbage collection only ever happens, if the app is sending AF_UNIX sockets over AF_UNIX sockets. Which is a rather rare case. And which is basically why this bug went unnoticed for so long. So my second patch only affects the performance of _exactly_ those apps which might well be bitten by the bug itself. > Secondarily, this bug has been around for years and nobody noticed. > The world will not explode if this bug takes a few more days or > even a week to work out. Let's do it right instead of ramming > arbitrary turds into the kernel. Fine, but just wishing a bug to get fixed won't accomplish anything. I've spent a fair amount of time debugging this thing, and I'm out of ideas. Really. So unless somebody steps up to look at this, it won't _ever_ get fixed. Miklos - 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/