From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from e1.ny.us.ibm.com ([32.97.182.141]) by pentafluge.infradead.org with esmtps (Exim 4.63 #1 (Red Hat Linux)) id 1IbrYE-00033C-HS for kexec@lists.infradead.org; Sun, 30 Sep 2007 06:41:15 +0100 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e1.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id l8U5buCx017809 for ; Sun, 30 Sep 2007 01:37:56 -0400 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v8.5) with ESMTP id l8U5brXc695674 for ; Sun, 30 Sep 2007 01:37:56 -0400 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l8U5brtZ028243 for ; Sun, 30 Sep 2007 01:37:53 -0400 Date: Sun, 30 Sep 2007 11:08:14 +0530 From: Vivek Goyal Subject: Re: [Kgdb-bugreport] Problem getting kgdb to read kernel symbols. addresses shifted? Message-ID: <20070930053813.GC16593@in.ibm.com> References: <46FD03CD.9060404@windriver.com> <46FD1B6A.3000500@windriver.com> <20070928114522.n0cdrcebykkgg408@webmail.mit.edu> <46FD2CFB.9010404@windriver.com> <46FD75E1.3090602@bluelane.com> Mime-Version: 1.0 Content-Disposition: inline In-Reply-To: Reply-To: vgoyal@in.ibm.com List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces@lists.infradead.org To: "Eric W. Biederman" Cc: Derek Atkins , kgdb-bugreport@lists.sourceforge.net, Kexec Mailing List , Dave Anderson , Jason Wessel , pete@bluelane.com On Fri, Sep 28, 2007 at 05:40:33PM -0600, Eric W. Biederman wrote: > Derek Atkins writes: > > > Well, gdb agrees with System.map, so I'm sure that gdb itself is > > okay. It's certainly possible that that the kgdb stub is weird, > > but /proc/kallsyms doesn't match System.map, and THAT'S what's > > confusing me most of all. > > Ok. So we must have a relocatable kernel that figures it has been > relocated. Interesting. > > What is your bootloader? > What is your kernel version? > What is your kernel config? > > The only time I would expect to see what you are seeing is if > you are debugging the kdump kernel, which doesn't sound like > the case. > > If we actually have a truly offset kernel then while things > may not be perfect this is at least expected. I don't think > I have heard of anyone handling this case very well. > Hi Eric and others, I think we might be running into the issues because i386, FC7 relocatable kernel has been compiled for 16MB physical address but effectively it runs at 4MB physical address. So kernel does not run at compiled address and any kind of debugging tools reading symbol address from System.map or rom vmlinux will fail as run time symbol addresses are different. /proc/kallsyms should help though. This is one problem with shift in run time virtual address while relocating the kernel. We should be running kernel at compiled address to be able to debug it. Or enable any tools to parse /proc/kallsyms to read the shift in symbol addresses and adjust accordingly. Thanks Vivek _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec