Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266490AbUFQNRM (ORCPT ); Thu, 17 Jun 2004 09:17:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266498AbUFQNRL (ORCPT ); Thu, 17 Jun 2004 09:17:11 -0400 Received: from mx2.elte.hu ([157.181.151.9]:51338 "EHLO mx2.elte.hu") by vger.kernel.org with ESMTP id S266490AbUFQNOR (ORCPT ); Thu, 17 Jun 2004 09:14:17 -0400 Date: Thu, 17 Jun 2004 15:15:30 +0200 From: Ingo Molnar To: Takao Indoh Cc: linux-kernel@vger.kernel.org, Christoph Hellwig , Andi Kleen Subject: Re: [3/4] [PATCH]Diskdump - yet another crash dump function Message-ID: <20040617131530.GA26155@elte.hu> References: <20040617121356.GA24338@elte.hu> <20040617131016.GA25920@elte.hu> <20040617131140.GA26107@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040617131140.GA26107@elte.hu> User-Agent: Mutt/1.4.1i X-ELTE-SpamVersion: MailScanner 4.26.8-itk2 (ELTE 1.1) SpamAssassin 2.63 ClamAV 0.65 X-ELTE-VirusStatus: clean X-ELTE-SpamCheck: no X-ELTE-SpamCheck-Details: score=-4.9, required 5.9, autolearn=not spam, BAYES_00 -4.90 X-ELTE-SpamLevel: X-ELTE-SpamScore: -4 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1328 Lines: 31 * Ingo Molnar wrote: > > yes it can be done safely - just INIT_LIST_HEAD() all the timer list > > heads - like init_timers_cpu() does. > > obviously this only involves the dumping CPU - no other CPU will run > any kernel code. On SMP you should also clear the timer spinlock of > the dumping CPU's timer base, if the crash happened within the timer > code. put another way: you can consider 'safe dumping' to involve a simplified bootup and initialization of the kernel's data structures that you need during the dump, to create a barrier for any (possibly corrupted) kernel data state prior the crash. you need to 'boot up' your dumping data structures, the driver (and hardware) you are going to use for dumping, and the timer code as well. (total separation is not possible because e.g. the dumping code's pagetable entries are a data structure too that could get corrupted - on the other hand complete separation is not necessary because crash statistics show that this is not a likely event - it is much more likely to get failure due to hw errors.) Ingo - 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/