From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751311AbdGPP7k (ORCPT ); Sun, 16 Jul 2017 11:59:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:41916 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751219AbdGPP7i (ORCPT ); Sun, 16 Jul 2017 11:59:38 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E45642133D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=mhiramat@kernel.org Date: Mon, 17 Jul 2017 00:59:35 +0900 From: Masami Hiramatsu To: Steven Rostedt Cc: Francis Deslauriers , mhiramat@kernel.org, peterz@infradead.org, mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/2] kprobe: Fix: add symbols to kprobe blacklist Message-Id: <20170717005935.dcdf6840d221a265c85f01e4@kernel.org> In-Reply-To: <20170714142756.7f7f1745@gandalf.local.home> References: <1500044315-9508-1-git-send-email-francis.deslauriers@efficios.com> <20170714142756.7f7f1745@gandalf.local.home> X-Mailer: Sylpheed 3.5.0 (GTK+ 2.24.31; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 14 Jul 2017 14:27:56 -0400 Steven Rostedt wrote: > On Fri, 14 Jul 2017 10:58:33 -0400 > Francis Deslauriers wrote: > > > > Kretprobe on ftrace_ops_assist_func and another function: > > Those crashes are triggered when hooking a kretprobe on the > > ftrace_ops_assist_func symbol and some other functions to make the this first > > function reacheable. From my understanding, ftrace_ops_assist_func is the > > function called directly when the kprobe is hit. Thus it should be marked > > with NOKPROBE_SYMBOL. > > > > Hmm, I'm wondering if I should just make an ftrace section, and black > list the entire thing. Also that section could be used to not allow > ftrace to use it either. I've been wanting to start letting ftrace > trace the tracing code, and perf for that matter. It would be nice to > be able to debug things like that. Tracer usually has 2 parts, one is off-line setting part (kicked by user) and another is core online tracing part (which kicked from anywhere). Former can be traced but latter is not. Yeah, I did same thing when I introduced NOKPROBE_SYMBOL() macro. And I also think that is good for kgdb. > I would like to also make sections that can be enabled or disabled in > groups. To group things like the tracing facility and perf and have > them by default not be traced, but then set a flag that says "sure go > ahead and trace them". This shouldn't be too hard to do. We have to notice that is a trigger which allows to shoot yourself in the foot :) Thanks, > > Hmm, I'll add this as another topic to have for the Linux Plumbers > tracing track, as well as the kernel tracing topic. > > -- Steve -- Masami Hiramatsu