Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755996AbZIKTPN (ORCPT ); Fri, 11 Sep 2009 15:15:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754411AbZIKTPJ (ORCPT ); Fri, 11 Sep 2009 15:15:09 -0400 Received: from mail-ew0-f227.google.com ([209.85.219.227]:41440 "EHLO mail-ew0-f227.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751984AbZIKTPI (ORCPT ); Fri, 11 Sep 2009 15:15:08 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=sZ7fk8OP7k82ZYOdzhCGgc5P4+j6FxauQc9tlqF0IOuaO0rdhGaVe4vW1tXiiJgmdr ES2IhNpFUG79InYNUliV9esBsSzpRU3z/zoyu2ECjBM95Utkzkr/nwbYhrqwGbTAbVG0 ZDoDr6qRkOgvaQn5CFNfOIGmp+fRsG39KqBiQ= Date: Fri, 11 Sep 2009 21:15:04 +0200 From: Frederic Weisbecker To: "Frank Ch. Eigler" Cc: Masami Hiramatsu , Steven Rostedt , Ingo Molnar , lkml , Ananth N Mavinakayanahalli , Andi Kleen , Christoph Hellwig , "H. Peter Anvin" , Jason Baron , Jim Keniston , "K.Prasad" , Lai Jiangshan , Li Zefan , Peter Zijlstra , Srikar Dronamraju , Tom Zanussi , systemtap , DLE Subject: Re: [PATCH tracing/kprobes 0/7] tracing/kprobes: kprobe-based event tracer update and perf support Message-ID: <20090911191502.GB4993@nowhere> References: <20090910235258.22412.29317.stgit@dhcp-100-2-132.bos.redhat.com> <20090911013332.GB16396@nowhere> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1599 Lines: 32 On Fri, Sep 11, 2009 at 03:03:35PM -0400, Frank Ch. Eigler wrote: > Frederic Weisbecker writes: > > > [...] I'm really looking forward seeing this C expression-like > > kprobe creation tool. It seems powerful enough to replace printk + > > kernel rebuild. No need anymore to write some printk to debug, > > worrying, [...] > > To a large extent, systemtap had delivered this already some years > ago, including the cushy ponies dancing in the sunlight. While such > low-level machinery is fine, some of our experience indicates that it > is dramatically easier to use if high-level, symbolic, debugging data > is used to compute probe locations and variable names/types/locations. > > It is also too easy to stress the low-level machinery beyond its > humble origins, in this case meaning putting probes in all kinds of > tender spots that go "ouch". The kprobes robustness patches coming in > are great and will benefit all of our efforts, but it will be awhile > until the kernel can survive a fuzz/crashme type stress test on that > subsystem. So expect ongoing effort there. Fully agreed! The more I see corner recursivity cases, the more I think we'll never fix every potential cases. But yeah it's worth trying to fix all of them that are reported/anticipated, the more such case are covered, the more it's usable. -- 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/