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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no 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 E3AEFC4CECE for ; Mon, 14 Oct 2019 15:17:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B91C321835 for ; Mon, 14 Oct 2019 15:17:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387444AbfJNPRW (ORCPT ); Mon, 14 Oct 2019 11:17:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:53208 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732397AbfJNPRW (ORCPT ); Mon, 14 Oct 2019 11:17:22 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 3BAC120854; Mon, 14 Oct 2019 15:17:21 +0000 (UTC) Date: Mon, 14 Oct 2019 11:17:19 -0400 From: Steven Rostedt To: Miroslav Benes Cc: mingo@redhat.com, jpoimboe@redhat.com, jikos@kernel.org, pmladek@suse.com, joe.lawrence@redhat.com, linux-kernel@vger.kernel.org, live-patching@vger.kernel.org Subject: Re: [PATCH v2] ftrace: Introduce PERMANENT ftrace_ops flag Message-ID: <20191014111719.141bd4fa@gandalf.local.home> In-Reply-To: <20191014105923.29607-1-mbenes@suse.cz> References: <20191014105923.29607-1-mbenes@suse.cz> X-Mailer: Claws Mail 3.17.3 (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: live-patching-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org On Mon, 14 Oct 2019 12:59:23 +0200 Miroslav Benes wrote: > int > ftrace_enable_sysctl(struct ctl_table *table, int write, > void __user *buffer, size_t *lenp, > @@ -6740,8 +6754,6 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, > if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled)) > goto out; > > - last_ftrace_enabled = !!ftrace_enabled; > - > if (ftrace_enabled) { > > /* we are starting ftrace again */ > @@ -6752,12 +6764,19 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, > ftrace_startup_sysctl(); > > } else { > + if (is_permanent_ops_registered()) { > + ftrace_enabled = last_ftrace_enabled; Although this is not incorrect, but may be somewhat confusing. At this location, last_ftrace_enabled is always true. I'm thinking this would be better to simply set it to false here. > + ret = -EBUSY; > + goto out; > + } > + > /* stopping ftrace calls (just send to ftrace_stub) */ > ftrace_trace_function = ftrace_stub; > > ftrace_shutdown_sysctl(); > } > > + last_ftrace_enabled = !!ftrace_enabled; > out: And move the assignment of last_ftrace_enabled to after the "out:" label. -- Steve > mutex_unlock(&ftrace_lock); > return ret;