From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5F55ECDFB0 for ; Fri, 13 Jul 2018 12:19:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 632C220871 for ; Fri, 13 Jul 2018 12:19:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 632C220871 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729797AbeGMMcb (ORCPT ); Fri, 13 Jul 2018 08:32:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:50042 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729646AbeGMMcb (ORCPT ); Fri, 13 Jul 2018 08:32:31 -0400 Received: from gandalf.local.home (cpe-66-24-56-78.stny.res.rr.com [66.24.56.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4361620871; Fri, 13 Jul 2018 12:18:05 +0000 (UTC) Date: Fri, 13 Jul 2018 08:18:03 -0400 From: Steven Rostedt To: Masami Hiramatsu Cc: Francis Deslauriers , peterz@infradead.org, mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] tracing: kprobes: Prohibit probing on notrace functions Message-ID: <20180713081803.1b78ebbc@gandalf.local.home> In-Reply-To: <20180713115301.532ab1484e8b0befd90782d0@kernel.org> References: <1500044315-9508-3-git-send-email-francis.deslauriers@efficios.com> <1531418053-21414-1-git-send-email-francis.deslauriers@efficios.com> <1531418053-21414-2-git-send-email-francis.deslauriers@efficios.com> <20180713115301.532ab1484e8b0befd90782d0@kernel.org> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 13 Jul 2018 11:53:01 +0900 Masami Hiramatsu wrote: > On Thu, 12 Jul 2018 13:54:12 -0400 > Francis Deslauriers wrote: > > > From: Masami Hiramatsu > > > > Prohibit kprobe-events probing on notrace function. > > Since probing on the notrace function can cause recursive > > event call. In most case those are just skipped, but > > in some case it falls into infinite recursive call. > > BTW, I'm considering to add an option to allow putting > kprobes on notrace function - just for debugging > ftrace by kprobes. That is "developer only" option > so generally it should be disabled, but for debugging > the ftrace, we still need it. Or should I introduce > another kprobes module for debugging it? No, I think the former is better (to add an option to allow putting kprobes on notrace functions). By default we let people protect themselves. But if then provide a switch that lets you do things that might let you shoot yourself in the foot. BTW, I'm now leaving on vacation. I'll be back on the 23rd and will be looking for patches that I should be pulling in then. Thanks! -- Steve