Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932485AbWEBHVX (ORCPT ); Tue, 2 May 2006 03:21:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932487AbWEBHVX (ORCPT ); Tue, 2 May 2006 03:21:23 -0400 Received: from pproxy.gmail.com ([64.233.166.176]:29464 "EHLO pproxy.gmail.com") by vger.kernel.org with ESMTP id S932485AbWEBHVW convert rfc822-to-8bit (ORCPT ); Tue, 2 May 2006 03:21:22 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=RCGvT8VWHl5JM5BPQbA31T4wqXr15r/BZPLkO/3PwFHv6aHj47qrmE3JEzZrWslGfGIm1V6siILkvwQc/6MiimEhD4GI1ltbu+LEU02ZVU/YUcH29XmZVWQOXTqkPqzcEqv6KxKoj6VttkFN0zjXGOnWlCLVus5BeRi9Z3pvk0w= Message-ID: Date: Tue, 2 May 2006 16:21:22 +0900 From: "Magnus Damm" To: "Andi Kleen" Subject: Re: [PATCH] kexec: Avoid overwriting the current pgd (x86_64) Cc: "Magnus Damm" , ebiederm@xmission.com, linux-kernel@vger.kernel.org, fastboot@lists.osdl.org In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7BIT Content-Disposition: inline References: <20060501095407.16902.78809.sendpatchset@cherry.local> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1057 Lines: 29 [re-added fastboot list] On 02 May 2006 08:45:59 +0200, Andi Kleen wrote: > Magnus Damm writes: > > > --===============82697867595349228== > > > > kexec: Avoid overwriting the current pgd (x86_64) > > > > This patch upgrades the x86_64-specific kexec code to avoid overwriting the > > current pgd. Overwriting the current pgd is bad when CONFIG_CRASH_DUMP is used > > to start a secondary kernel that dumps the memory of the previous kernel. > > Why is it bad? Because in the kdump case (CONFIG_CRASH_DUMP) we store the memory contents of the crashed kernel somewhere to later on be able to analyze it. And it makes sense to avoid overwriting things because we want to analyze the _original_ state when the kernel crashed, not some half-overwritten state. Thanks, / magnus - 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/