On Wed, 19 Feb 2020 15:14:10 +0200
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx> wrote:
> The "trace-cmd reset" command is supposed to set the ftrace state to default.
> However, the ftrace error logs are not reseted.
> A logic is added to delete the content of "error_log" file when "trace-cmd reset" is executed.
>
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
> ---
> tracecmd/trace-record.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
> index b6a412e..3e0d066 100644
> --- a/tracecmd/trace-record.c
> +++ b/tracecmd/trace-record.c
> @@ -4638,6 +4638,25 @@ static void clear_triggers(void)
> clear_instance_triggers(instance);
> }
>
> +static void clear_instance_error_log(struct buffer_instance *instance)
> +{
> + char *file;
> +
> + file = tracefs_instance_get_file(instance->tracefs, "error_log");
> + if (!file)
> + return;
> + write_file(file, " ");
> + tracefs_put_tracing_file(file);
> +}
The error_log file is not guaranteed to exist. Please add a check for
existence via stat() (hmm, perhaps we should make a file_exists() helper
function). Otherwise I get this:
# trace-cmd reset
trace-cmd: No such file or directory
opening to '/debug/tracing/error_log'
> +
> +static void clear_error_log(void)
> +{
> + struct buffer_instance *instance;
> +
> + for_all_instances(instance)
> + clear_instance_error_log(instance);
> +}
> +
> static void clear_all_synth_events(void)
> {
> char sevent[BUFSIZ];
> @@ -5382,6 +5401,7 @@ void trace_reset(int argc, char **argv)
> clear_filters();
> clear_triggers();
> clear_all_synth_events();
> + clear_error_log();
> /* set clock to "local" */
> reset_clock();
> reset_event_pid();
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