Messages in this thread | | | Date | Wed, 7 Sep 2022 17:46:04 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH 2/2] tracefs: Only clobber mode/uid/gid on remount if asked |
| |
On Fri, 26 Aug 2022 17:44:17 -0700 Brian Norris <briannorris@chromium.org> wrote:
> Users may have explicitly configured their tracefs permissions; we > shouldn't overwrite those just because a second mount appeared. > > Only clobber if the options were provided at mount time. > > Note: the previous behavior was especially surprising in the presence of > automounted /sys/kernel/debug/tracing/. > > # Don't change /sys/kernel/tracing/ permissions on automount. > umount /sys/kernel/debug/tracing/
BTW, I noticed that the above doesn't do anything. That is, you cannot unmount tracefs from /sys/kernel/debug/tracing.
# ls /sys/kernel/debug/tracing/ available_events buffer_total_size_kb error_log hwlat_detector options recursed_functions set_event_notrace_pid set_ftrace_pid stack_trace trace_clock trace_stat uprobe_events available_filter_functions current_tracer eval_map instances osnoise saved_cmdlines set_event_pid set_graph_function stack_trace_filter trace_marker tracing_cpumask uprobe_profile available_tracers dynamic_events events kprobe_events per_cpu saved_cmdlines_size set_ftrace_filter set_graph_notrace synthetic_events trace_marker_raw tracing_max_latency user_events_data buffer_percent dyn_ftrace_total_info free_buffer kprobe_profile printk_formats saved_tgids set_ftrace_notrace snapshot timestamp_mode trace_options tracing_on user_events_status buffer_size_kb enabled_functions function_profile_enabled max_graph_depth README set_event set_ftrace_notrace_pid stack_max_size trace trace_pipe tracing_thresh
# umount /sys/kernel/debug/tracing/
# ls /sys/kernel/debug/tracing/ available_events buffer_total_size_kb error_log hwlat_detector options recursed_functions set_event_notrace_pid set_ftrace_pid stack_trace trace_clock trace_stat uprobe_events available_filter_functions current_tracer eval_map instances osnoise saved_cmdlines set_event_pid set_graph_function stack_trace_filter trace_marker tracing_cpumask uprobe_profile available_tracers dynamic_events events kprobe_events per_cpu saved_cmdlines_size set_ftrace_filter set_graph_notrace synthetic_events trace_marker_raw tracing_max_latency user_events_data buffer_percent dyn_ftrace_total_info free_buffer kprobe_profile printk_formats saved_tgids set_ftrace_notrace snapshot timestamp_mode trace_options tracing_on user_events_status buffer_size_kb enabled_functions function_profile_enabled max_graph_depth README set_event set_ftrace_notrace_pid stack_max_size trace trace_pipe tracing_thresh
-- Steve
> stat /sys/kernel/debug/tracing/. > > # Don't change /sys/kernel/tracing/ permissions. > mount -t tracefs none /mnt/foo > > # Change /sys/kernel/tracing/ mode and uid, but not gid. > mount -t tracefs -o uid=bar,mode=0750 none /mnt/baz > > Signed-off-by: Brian Norris <briannorris@chromium.org> > --- >
| |