From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756715AbYE3LJq (ORCPT ); Fri, 30 May 2008 07:09:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753444AbYE3LJf (ORCPT ); Fri, 30 May 2008 07:09:35 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:45355 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753613AbYE3LJe (ORCPT ); Fri, 30 May 2008 07:09:34 -0400 Date: Fri, 30 May 2008 13:09:04 +0200 From: Ingo Molnar To: Ilpo J?rvinen Cc: LKML , Netdev , "David S. Miller" , "Rafael J. Wysocki" , Andrew Morton Subject: Re: [bug] stuck localhost TCP connections, v2.6.26-rc3+ Message-ID: <20080530110904.GA14184@elte.hu> References: <20080526115628.GA31316@elte.hu> <20080529084524.GA24892@elte.hu> <20080529112257.GA18130@elte.hu> <20080529130823.GA8364@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080529130823.GA8364@elte.hu> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Ingo Molnar wrote: > btw., i now also have a hung socket over real network: last night i turned off distcc support, and got about 200 successful bootups and zero TCP hangs (as expected - there's not much TCP traffic if the distcc cluster is not utilized). but that's 200 overnight tests instead of the expected 600, so this is a major and rather crippling bug to me. There's no good way to detect these hung sockets by me from userspace and get rid of them. Has anyone before thought of the obvious: to write a kernel-space "TCP socket watchdog" kernel feature that detects them and tries to free them so that people can become aware of it? Hung sockets is a re-occuring bug in the TCP stack after all. (and it's a natural property of it: state machine designs are always vulnerable to lost event problems.) Ingo