Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261681AbVCIOVW (ORCPT ); Wed, 9 Mar 2005 09:21:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261716AbVCIOVW (ORCPT ); Wed, 9 Mar 2005 09:21:22 -0500 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:11488 "EHLO ebiederm.dsl.xmission.com") by vger.kernel.org with ESMTP id S261681AbVCIOVT (ORCPT ); Wed, 9 Mar 2005 09:21:19 -0500 To: Vivek Goyal Cc: Andrew Morton , Dave Anderson , gdb , fastboot , lkml Subject: Re: [Fastboot] Re: Query: Kdump: Core Image ELF Format References: <1110286210.4195.27.camel@wks126478wss.in.ibm.com> <1110350629.31878.7.camel@wks126478wss.in.ibm.com> From: ebiederm@xmission.com (Eric W. Biederman) Date: 09 Mar 2005 07:17:49 -0700 In-Reply-To: <1110350629.31878.7.camel@wks126478wss.in.ibm.com> Message-ID: User-Agent: Gnus/5.0808 (Gnus v5.8.8) Emacs/21.2 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1740 Lines: 32 Vivek Goyal writes: > On Tue, 2005-03-08 at 11:00 -0700, Eric W. Biederman wrote: > That sounds good. But we loose the advantage of doing limited debugging > with gdb. Crash (or other analysis tools) will still take considerable > amount of time before before they are fully ready and tested. > > How about giving user the flexibility to choose. What I mean is > introducing a command line option in kexec-tools to choose between ELF32 > and ELF64 headers. For the users who are not using PAE systems, they can > very well go with ELF32 headers and do the debugging using gdb. > > This also requires, setting the kernel virtual addresses while preparing > the headers. KVA for linearly mapped region is known in advance and can > be filled at header creation time and gdb can directly operate upon this > region. I have no problems decorating the ELF header you are generating in user space with virtual addresses assuming we can reliably get that information. And before a kernel crashes looks like a reasonable time to ask that question. I don't currently see where you could derive that information. Beyond that I prefer a little command line tool that will do the ELF64 to ELF32 conversion and possibly add in the kva mapping to make the core dump usable with gdb. Doing it in a separate tool means it is the developer who is doing the analysis who cares not the user who is capturing the system core dump. But I do agree that it a use case worth solving. Eric - 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/