perf report: Free generated help strings for sort option

ASan reports the memory leak of the strings allocated by sort_help() when
running perf report.

This patch changes the returned pointer to char* (instead of const
char*), saves it in a temporary variable, and finally deallocates it at
function exit.

Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Fixes: 702fb9b ("perf report: Show all sort keys in help output")
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/a38b13f02812a8a6759200b9063c6191337f44d4.1626343282.git.rickyman7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-report.c

@@ -1175,6 +1175,8 @@ int cmd_report(int argc, const char **argv)
 		.annotation_opts	 = annotation__default_options,
 		.skip_empty		 = true,
 	};
+	char *sort_order_help = sort_help("sort by key(s):");
+	char *field_order_help = sort_help("output field(s): overhead period sample ");
 	const struct option options[] = {
 	OPT_STRING('i', "input", &input_name, "file",
 		    "input file name"),
@@ -1209,9 +1211,9 @@ int cmd_report(int argc, const char **argv)
 	OPT_BOOLEAN(0, "header-only", &report.header_only,
 		    "Show only data header."),
 	OPT_STRING('s', "sort", &sort_order, "key[,key2...]",
-		   sort_help("sort by key(s):")),
+		   sort_order_help),
 	OPT_STRING('F', "fields", &field_order, "key[,keys...]",
-		   sort_help("output field(s): overhead period sample ")),
+		   field_order_help),
 	OPT_BOOLEAN(0, "show-cpu-utilization", &symbol_conf.show_cpu_utilization,
 		    "Show sample percentage for different cpu modes"),
 	OPT_BOOLEAN_FLAG(0, "showcpuutilization", &symbol_conf.show_cpu_utilization,
@@ -1344,11 +1346,11 @@ int cmd_report(int argc, const char **argv)
 	char sort_tmp[128];
 
 	if (ret < 0)
-		return ret;
+		goto exit;
 
 	ret = perf_config(report__config, &report);
 	if (ret)
-		return ret;
+		goto exit;
 
 	argc = parse_options(argc, argv, options, report_usage, 0);
 	if (argc) {
@@ -1362,8 +1364,10 @@ int cmd_report(int argc, const char **argv)
 		report.symbol_filter_str = argv[0];
 	}
 
-	if (annotate_check_args(&report.annotation_opts) < 0)
-		return -EINVAL;
+	if (annotate_check_args(&report.annotation_opts) < 0) {
+		ret = -EINVAL;
+		goto exit;
+	}
 
 	if (report.mmaps_mode)
 		report.tasks_mode = true;
@@ -1377,12 +1381,14 @@ int cmd_report(int argc, const char **argv)
 	if (symbol_conf.vmlinux_name &&
 	    access(symbol_conf.vmlinux_name, R_OK)) {
 		pr_err("Invalid file: %s\n", symbol_conf.vmlinux_name);
-		return -EINVAL;
+		ret = -EINVAL;
+		goto exit;
 	}
 	if (symbol_conf.kallsyms_name &&
 	    access(symbol_conf.kallsyms_name, R_OK)) {
 		pr_err("Invalid file: %s\n", symbol_conf.kallsyms_name);
-		return -EINVAL;
+		ret = -EINVAL;
+		goto exit;
 	}
 
 	if (report.inverted_callchain)
@@ -1406,12 +1412,14 @@ int cmd_report(int argc, const char **argv)
 
 repeat:
 	session = perf_session__new(&data, false, &report.tool);
-	if (IS_ERR(session))
-		return PTR_ERR(session);
+	if (IS_ERR(session)) {
+		ret = PTR_ERR(session);
+		goto exit;
+	}
 
 	ret = evswitch__init(&report.evswitch, session->evlist, stderr);
 	if (ret)
-		return ret;
+		goto exit;
 
 	if (zstd_init(&(session->zstd_data), 0) < 0)
 		pr_warning("Decompression initialization failed. Reported data may be incomplete.\n");
@@ -1646,5 +1654,8 @@ int cmd_report(int argc, const char **argv)
 
 	zstd_fini(&(session->zstd_data));
 	perf_session__delete(session);
+exit:
+	free(sort_order_help);
+	free(field_order_help);
 	return ret;
 }

tools/perf/util/sort.c

@@ -3370,7 +3370,7 @@ static void add_hpp_sort_string(struct strbuf *sb, struct hpp_dimension *s, int
 		add_key(sb, s[i].name, llen);
 }
 
-const char *sort_help(const char *prefix)
+char *sort_help(const char *prefix)
 {
 	struct strbuf sb;
 	char *s;

tools/perf/util/sort.h

@@ -302,7 +302,7 @@ void reset_output_field(void);
 void sort__setup_elide(FILE *fp);
 void perf_hpp__set_elide(int idx, bool elide);
 
-const char *sort_help(const char *prefix);
+char *sort_help(const char *prefix);
 
 int report_parse_ignore_callees_opt(const struct option *opt, const char *arg, int unset);