From: Steven Rostedt <rostedt@goodmis.org>
To: Brian Norris <briannorris@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] tracefs: Only clobber mode/uid/gid on remount if asked
Date: Wed, 7 Sep 2022 18:45:24 -0400 [thread overview]
Message-ID: <20220907184524.0dfb3a8a@gandalf.local.home> (raw)
In-Reply-To: <YxkS5uzouv2bn6ZB@google.com>
On Wed, 7 Sep 2022 14:53:42 -0700
Brian Norris <briannorris@chromium.org> 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
next prev parent reply other threads:[~2022-09-07 22:44 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-27 0:44 [PATCH 1/2] debugfs: Only clobber mode/uid/gid on remount if asked Brian Norris
2022-08-27 0:44 ` [PATCH 2/2] tracefs: " Brian Norris
2022-09-07 11:44 ` Steven Rostedt
2022-09-07 20:52 ` Brian Norris
2022-09-08 1:25 ` Steven Rostedt
2022-09-07 21:46 ` Steven Rostedt
2022-09-07 21:48 ` Steven Rostedt
2022-09-07 21:53 ` Brian Norris
2022-09-07 22:45 ` Steven Rostedt [this message]
2022-09-01 15:58 ` [PATCH 1/2] debugfs: " Greg Kroah-Hartman
2022-09-01 16:11 ` Steven Rostedt
2022-09-01 22:32 ` Brian Norris
2022-09-02 5:45 ` Greg Kroah-Hartman
2022-09-09 0:16 ` Brian Norris
2022-09-09 0:43 ` Steven Rostedt
2022-09-09 0:57 ` Brian Norris
2022-09-09 1:05 ` Steven Rostedt
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