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=-1.0 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 7AA9BC28CF6 for ; Wed, 1 Aug 2018 20:07:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3BC59208A4 for ; Wed, 1 Aug 2018 20:07:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3BC59208A4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linutronix.de 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 S1732078AbeHAVym (ORCPT ); Wed, 1 Aug 2018 17:54:42 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:34865 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726788AbeHAVym (ORCPT ); Wed, 1 Aug 2018 17:54:42 -0400 Received: from p4fea5a5a.dip0.t-ipconnect.de ([79.234.90.90] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1fkxOr-0001YQ-9u; Wed, 01 Aug 2018 22:07:13 +0200 Date: Wed, 1 Aug 2018 22:07:12 +0200 (CEST) From: Thomas Gleixner To: Steven Rostedt cc: Erica Bugden , linux-kernel@vger.kernel.org, peterz@infradead.org, anna-maria@linutronix.de, bigeasy@linutronix.de Subject: Re: [PATCH] ftrace: Add missing check for existing hwlat thread In-Reply-To: <20180801160320.3a4c63f7@gandalf.local.home> Message-ID: References: <1533120354-22923-1-git-send-email-erica.bugden@linutronix.de> <20180801154006.580806cc@gandalf.local.home> <20180801160320.3a4c63f7@gandalf.local.home> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 1 Aug 2018, Steven Rostedt wrote: > On Wed, 1 Aug 2018 21:59:38 +0200 (CEST) > Thomas Gleixner wrote: > > > > This looks like it is treating the symptom and not the disease. > > > > My bad. We looked at the other instances of tracers and they all have > > protection against this kind of call sequence ... > > Probably because they were all fixing the symptom ;-) :) > I'm going to keep Erica's patch and add a WARN_ON() to it just in case. > But can you still check if the patch I gave fixes it too? Sure