linux-kernel - Re: [PATCH v2 3/4] perf tools: Check NULL after zalloc() and Use zfree() instead of free() in parse-events.c

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Message-ID: <20170131132335.GE4491@kernel.org>
Date:   Tue, 31 Jan 2017 10:23:35 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Taeung Song <treeze.taeung@...il.com>
Cc:     linux-kernel@...r.kernel.org, Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Wang Nan <wangnan0@...wei.com>, Jiri Olsa <jolsa@...hat.com>
Subject: Re: [PATCH v2 3/4] perf tools: Check NULL after zalloc() and Use
 zfree() instead of free() in parse-events.c

Em Tue, Jan 31, 2017 at 08:38:30PM +0900, Taeung Song escreveu:
> Currently there are several parts not checking NULL
> after allocating with zalloc() or asigning NULL value
> to a pointer variable after doing free().
> 
> So I fill in code checking NULL and
> use zfree() instead of free().

You are doing more than one thing on this patch, don't do that.

Please split it for the "no functional changes" parts, i.e. things like

-		free(path);
-		path = NULL;
+		zfree(&path);

>From the ones that _change_ logic, like the first hunk:

 				path = zalloc(sizeof(*path));
+				if (!path)
+					return NULL;
 				path->system = malloc(MAX_EVENT_LENGTH);
 				if (!path->system) {
 					free(path);

This one as well changes logic:

@@ -1563,7 +1563,7 @@ perf_pmu__parse_check(const char *name)
 	r = bsearch(&p, perf_pmu_events_list,
 			(size_t) perf_pmu_events_list_num,
 			sizeof(struct perf_pmu_event_symbol), comp_pmu);
-	free(p.symbol);
+	zfree(&p.symbol);
 	return r ? r->type : PMU_EVENT_SYMBOL_ERR;

 
> Cc: Namhyung Kim <namhyung@...nel.org>
> Cc: Jiri Olsa <jolsa@...hat.com>
> Signed-off-by: Taeung Song <treeze.taeung@...il.com>
> ---
>  tools/perf/util/parse-events.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
> 
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index 3c876b8..87a3e5a 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -211,6 +211,8 @@ struct tracepoint_path *tracepoint_id_to_path(u64 config)
>  				closedir(evt_dir);
>  				closedir(sys_dir);
>  				path = zalloc(sizeof(*path));
> +				if (!path)
> +					return NULL;
>  				path->system = malloc(MAX_EVENT_LENGTH);
>  				if (!path->system) {
>  					free(path);
> @@ -252,8 +254,7 @@ struct tracepoint_path *tracepoint_name_to_path(const char *name)
>  	if (path->system == NULL || path->name == NULL) {
>  		zfree(&path->system);
>  		zfree(&path->name);
> -		free(path);
> -		path = NULL;
> +		zfree(&path);
>  	}
>  
>  	return path;
> @@ -1477,10 +1478,9 @@ static void perf_pmu__parse_cleanup(void)
>  
>  		for (i = 0; i < perf_pmu_events_list_num; i++) {
>  			p = perf_pmu_events_list + i;
> -			free(p->symbol);
> +			zfree(&p->symbol);
>  		}
> -		free(perf_pmu_events_list);
> -		perf_pmu_events_list = NULL;
> +		zfree(&perf_pmu_events_list);
>  		perf_pmu_events_list_num = 0;
>  	}
>  }
> @@ -1563,7 +1563,7 @@ perf_pmu__parse_check(const char *name)
>  	r = bsearch(&p, perf_pmu_events_list,
>  			(size_t) perf_pmu_events_list_num,
>  			sizeof(struct perf_pmu_event_symbol), comp_pmu);
> -	free(p.symbol);
> +	zfree(&p.symbol);
>  	return r ? r->type : PMU_EVENT_SYMBOL_ERR;
>  }
>  
> @@ -1710,8 +1710,8 @@ static void parse_events_print_error(struct parse_events_error *err,
>  		fprintf(stderr, "%*s\\___ %s\n", idx + 1, "", err->str);
>  		if (err->help)
>  			fprintf(stderr, "\n%s\n", err->help);
> -		free(err->str);
> -		free(err->help);
> +		zfree(&err->str);
> +		zfree(&err->help);
>  	}
>  
>  	fprintf(stderr, "Run 'perf list' for a list of valid events\n");
> @@ -2406,7 +2406,7 @@ void parse_events_terms__purge(struct list_head *terms)
>  
>  	list_for_each_entry_safe(term, h, terms, list) {
>  		if (term->array.nr_ranges)
> -			free(term->array.ranges);
> +			zfree(&term->array.ranges);
>  		list_del_init(&term->list);
>  		free(term);
>  	}
> @@ -2422,7 +2422,7 @@ void parse_events_terms__delete(struct list_head *terms)
>  
>  void parse_events__clear_array(struct parse_events_array *a)
>  {
> -	free(a->ranges);
> +	zfree(&a->ranges);
>  }
>  
>  void parse_events_evlist_error(struct parse_events_evlist *data,
> -- 
> 2.7.4