Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755999AbYGRJLj (ORCPT ); Fri, 18 Jul 2008 05:11:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753304AbYGRJLc (ORCPT ); Fri, 18 Jul 2008 05:11:32 -0400 Received: from smtp-out01.alice-dsl.net ([88.44.60.11]:32467 "EHLO smtp-out01.alice-dsl.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752831AbYGRJLb (ORCPT ); Fri, 18 Jul 2008 05:11:31 -0400 To: James Bottomley Cc: linux-kernel , systemtap@sourceware.org, jbeulich@novell.com Subject: Re: [RFC] systemtap: begin the process of using proper kernel APIs (part1: use kprobe symbol_name/offset instead of address) From: Andi Kleen References: <1216146802.3312.95.camel@localhost.localdomain> Date: Fri, 18 Jul 2008 11:11:07 +0200 In-Reply-To: <1216146802.3312.95.camel@localhost.localdomain> (James Bottomley's message of "Tue, 15 Jul 2008 13:33:22 -0500") Message-ID: <87ej5rsgk4.fsf@basil.nowhere.org> User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/21.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-OriginalArrivalTime: 18 Jul 2008 09:11:05.0564 (UTC) FILETIME=[3547A9C0:01C8E8B6] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1394 Lines: 34 James Bottomley writes: > One of the big nasties of systemtap is the way it tries to embed > virtually the entirety of the kernel symbol table in the probe modules > it constructs. This is highly undesirable because it represents a > subversion of the kernel API to gain access to unexported symbols. At > least for kprobes, the correct way to do this is to specify the probe > point by symbol and offset. > > This patch converts systemtap to use the correct kprobe > symbol_name/offset pair to identify the probe location. > > This only represents a baby step: after this is done, there are at > least three other consumers of the systemtap module relocation > machinery: > > 1. unwind information. I think the consumers of this can be > converted to use the arch specific unwinders that already exist > within the kernel Right now x86 doesn't really have a good reliable unwinder that works without frame pointer. I think systemtap recently switched to Jan Beulich's dwarf2 unwinder. Before switching to the in kernel unwinder that one would need to be re-merged again. -Andi -- 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/