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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 24578C54EE9 for ; Wed, 7 Sep 2022 22:44:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229620AbiIGWov (ORCPT ); Wed, 7 Sep 2022 18:44:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33216 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229653AbiIGWor (ORCPT ); Wed, 7 Sep 2022 18:44:47 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F26E128E38 for ; Wed, 7 Sep 2022 15:44:45 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 82C7A61AF5 for ; Wed, 7 Sep 2022 22:44:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 691B1C433C1; Wed, 7 Sep 2022 22:44:44 +0000 (UTC) Date: Wed, 7 Sep 2022 18:45:24 -0400 From: Steven Rostedt To: Brian Norris Cc: Greg Kroah-Hartman , "Rafael J . Wysocki" , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] tracefs: Only clobber mode/uid/gid on remount if asked Message-ID: <20220907184524.0dfb3a8a@gandalf.local.home> In-Reply-To: References: <20220826174353.1.Icbd40fce59f55ad74b80e5d435ea233579348a78@changeid> <20220826174353.2.Iab6e5ea57963d6deca5311b27fb7226790d44406@changeid> <20220907174604.06809ff2@gandalf.local.home> <20220907174813.182df339@gandalf.local.home> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 7 Sep 2022 14:53:42 -0700 Brian Norris wrote: > Try these: > > umount /sys/kernel/debug/tracing/ > grep tracefs /proc/mounts > stat /sys/kernel/debug/tracing/. > grep tracefs /proc/mounts > > The first and the second grep will give you different results. How about this: # grep tracefs /proc/mounts tracefs /sys/kernel/tracing tracefs rw,nosuid,nodev,noexec,relatime 0 0 tracefs /sys/kernel/debug/tracing tracefs rw,nosuid,nodev,noexec,relatime 0 0 # umount /sys/kernel/debug/tracing # grep tracefs /proc/mounts tracefs /sys/kernel/tracing tracefs rw,nosuid,nodev,noexec,relatime 0 0 # ls /sys/kernel/debug/tracing available_events hwlat_detector set_event_notrace_pid trace_clock available_filter_functions instances set_event_pid trace_marker available_tracers kprobe_events set_ftrace_filter trace_marker_raw buffer_percent kprobe_profile set_ftrace_notrace trace_options buffer_size_kb max_graph_depth set_ftrace_notrace_pid trace_pipe buffer_total_size_kb options set_ftrace_pid trace_stat current_tracer osnoise set_graph_function tracing_cpumask dynamic_events per_cpu set_graph_notrace tracing_max_latency dyn_ftrace_total_info printk_formats snapshot tracing_on enabled_functions README stack_max_size tracing_thresh error_log recursed_functions stack_trace uprobe_events eval_map saved_cmdlines stack_trace_filter uprobe_profile events saved_cmdlines_size synthetic_events user_events_data free_buffer saved_tgids timestamp_mode user_events_status function_profile_enabled set_event trace # grep tracefs /proc/mounts tracefs /sys/kernel/tracing tracefs rw,nosuid,nodev,noexec,relatime 0 0 tracefs /sys/kernel/debug/tracing tracefs rw,nosuid,nodev,noexec,relatime 0 0 So it appears that accessing debugfs/tracing will automatically remount it. Lean something new everyday! ;-) -- Steve