linux-kernel - Re: [PATCH 3/4] tracing: Add action comparisons when testing matching hist triggers

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Date:   Tue, 3 Apr 2018 00:10:25 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Tom Zanussi <tom.zanussi@...ux.intel.com>
Cc:     rostedt@...dmis.org, tglx@...utronix.de, mhiramat@...nel.org,
        namhyung@...nel.org, vedang.patel@...el.com, bigeasy@...utronix.de,
        joel.opensrc@...il.com, joelaf@...gle.com,
        mathieu.desnoyers@...icios.com, baohong.liu@...el.com,
        rajvi.jingar@...el.com, julia@...com, fengguang.wu@...el.com,
        linux-kernel@...r.kernel.org, linux-rt-users@...r.kernel.org
Subject: Re: [PATCH 3/4] tracing: Add action comparisons when testing
 matching hist triggers

On Wed, 28 Mar 2018 15:10:55 -0500
Tom Zanussi <tom.zanussi@...ux.intel.com> wrote:

> Actions also need to be considered when checking for matching triggers
> - triggers differing only by action should be allowed, but currently
> aren't because the matching check ignores the action and erroneously
> returns -EEXIST.

Hi Tom,

Could you show us the bad/good examples (maybe different onmatch() actions)?
And if it is real bugfix, I would like to add a ftracetest testcase for this fix.

Thank you,

> 
> Add and call an actions_match() function to address that.
> 
> Signed-off-by: Tom Zanussi <tom.zanussi@...ux.intel.com>
> ---
>  kernel/trace/trace_events_hist.c | 50 ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 50 insertions(+)
> 
> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index 468e43f..ae84470 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -4363,6 +4363,53 @@ static void print_onmatch_spec(struct seq_file *m,
>  	seq_puts(m, ")");
>  }
>  
> +static bool actions_match(struct hist_trigger_data *hist_data,
> +			  struct hist_trigger_data *hist_data_test)
> +{
> +	unsigned int i, j;
> +
> +	if (hist_data->n_actions != hist_data_test->n_actions)
> +		return false;
> +
> +	for (i = 0; i < hist_data->n_actions; i++) {
> +		struct action_data *data = hist_data->actions[i];
> +		struct action_data *data_test = hist_data_test->actions[i];
> +
> +		if (data->fn != data_test->fn)
> +			return false;
> +
> +		if (data->n_params != data_test->n_params)
> +			return false;
> +
> +		for (j = 0; j < data->n_params; j++) {
> +			if (strcmp(data->params[j], data_test->params[j]) != 0)
> +				return false;
> +		}
> +
> +		if (data->fn == action_trace) {
> +			if (strcmp(data->onmatch.synth_event_name,
> +				   data_test->onmatch.synth_event_name) != 0)
> +				return false;
> +			if (strcmp(data->onmatch.match_event_system,
> +				   data_test->onmatch.match_event_system) != 0)
> +				return false;
> +			if (strcmp(data->onmatch.match_event,
> +				   data_test->onmatch.match_event) != 0)
> +				return false;
> +		} else if (data->fn == onmax_save) {
> +			if (strcmp(data->onmax.var_str,
> +				   data_test->onmax.var_str) != 0)
> +				return false;
> +			if (strcmp(data->onmax.fn_name,
> +				   data_test->onmax.fn_name) != 0)
> +				return false;
> +		}
> +	}
> +
> +	return true;
> +}
> +
> +
>  static void print_actions_spec(struct seq_file *m,
>  			       struct hist_trigger_data *hist_data)
>  {
> @@ -5173,6 +5220,9 @@ static bool hist_trigger_match(struct event_trigger_data *data,
>  	    (strcmp(data->filter_str, data_test->filter_str) != 0))
>  		return false;
>  
> +	if (!actions_match(hist_data, hist_data_test))
> +		return false;
> +
>  	return true;
>  }
>  
> -- 
> 1.9.3
> 


-- 
Masami Hiramatsu <mhiramat@...nel.org>