[PATCH v1 2/3] perf kwork: Fix address sanitizer issues

[Ian Rogers <irogers@google.com>]

There is a double free in the record array due to how parse_options
will mutate the array. Fix by keeping an array that isn't
mutated. Ensure kwork_usage is freed on all paths.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/builtin-kwork.c | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/tools/perf/builtin-kwork.c b/tools/perf/builtin-kwork.c
index 59a54d11f7fa..a4604e152002 100644
--- a/tools/perf/builtin-kwork.c
+++ b/tools/perf/builtin-kwork.c
@@ -2258,7 +2258,7 @@ static void setup_event_list(struct perf_kwork *kwork,
 static int perf_kwork__record(struct perf_kwork *kwork,
 			      int argc, const char **argv)
 {
-	const char **rec_argv;
+	const char **rec_argv, **to_free = NULL;
 	unsigned int rec_argc, i, j;
 	struct kwork_class *class;
 	int ret;
@@ -2295,16 +2295,27 @@ static int perf_kwork__record(struct perf_kwork *kwork,
 
 	BUG_ON(i != rec_argc);
 
+	/* Save the pointers as the array will be mutated by cmd_record. */
+	to_free = calloc(rec_argc + 1, sizeof(char *));
+	if (to_free == NULL) {
+		ret = -ENOMEM;
+		goto EXIT;
+	}
+
 	pr_debug("record comm: ");
-	for (j = 0; j < rec_argc; j++)
+	for (j = 0; j < rec_argc; j++) {
 		pr_debug("%s ", rec_argv[j]);
+		to_free[j] = rec_argv[j];
+	}
 	pr_debug("\n");
 
 	ret = cmd_record(i, rec_argv);
 
 EXIT:
 	for (i = 0; i < rec_argc; i++)
-		free((void *)rec_argv[i]);
+		free((void *)(to_free ? to_free[i] : rec_argv[i]));
+
+	free(to_free);
 	free(rec_argv);
 	return ret;
 }
@@ -2447,6 +2458,7 @@ int cmd_kwork(int argc, const char **argv)
 	const char *const kwork_subcommands[] = {
 		"record", "report", "latency", "timehist", "top", NULL
 	};
+	int ret = 0;
 
 	perf_tool__init(&kwork.tool, /*ordered_events=*/true);
 	kwork.tool.mmap	  = perf_event__process_mmap;
@@ -2463,7 +2475,7 @@ int cmd_kwork(int argc, const char **argv)
 
 	if (strlen(argv[0]) > 2 && strstarts("record", argv[0])) {
 		setup_event_list(&kwork, kwork_options, kwork_usage);
-		return perf_kwork__record(&kwork, argc, argv);
+		ret = perf_kwork__record(&kwork, argc, argv);
 	} else if (strlen(argv[0]) > 2 && strstarts("report", argv[0])) {
 		kwork.sort_order = default_report_sort_order;
 		if (argc > 1) {
@@ -2474,7 +2486,7 @@ int cmd_kwork(int argc, const char **argv)
 		kwork.report = KWORK_REPORT_RUNTIME;
 		setup_sorting(&kwork, report_options, report_usage);
 		setup_event_list(&kwork, kwork_options, kwork_usage);
-		return perf_kwork__report(&kwork);
+		ret = perf_kwork__report(&kwork);
 	} else if (strlen(argv[0]) > 2 && strstarts("latency", argv[0])) {
 		kwork.sort_order = default_latency_sort_order;
 		if (argc > 1) {
@@ -2485,7 +2497,7 @@ int cmd_kwork(int argc, const char **argv)
 		kwork.report = KWORK_REPORT_LATENCY;
 		setup_sorting(&kwork, latency_options, latency_usage);
 		setup_event_list(&kwork, kwork_options, kwork_usage);
-		return perf_kwork__report(&kwork);
+		ret = perf_kwork__report(&kwork);
 	} else if (strlen(argv[0]) > 2 && strstarts("timehist", argv[0])) {
 		if (argc > 1) {
 			argc = parse_options(argc, argv, timehist_options, timehist_usage, 0);
@@ -2494,7 +2506,7 @@ int cmd_kwork(int argc, const char **argv)
 		}
 		kwork.report = KWORK_REPORT_TIMEHIST;
 		setup_event_list(&kwork, kwork_options, kwork_usage);
-		return perf_kwork__timehist(&kwork);
+		ret = perf_kwork__timehist(&kwork);
 	} else if (strlen(argv[0]) > 2 && strstarts("top", argv[0])) {
 		kwork.sort_order = default_top_sort_order;
 		if (argc > 1) {
@@ -2507,12 +2519,12 @@ int cmd_kwork(int argc, const char **argv)
 			kwork.event_list_str = "sched, irq, softirq";
 		setup_event_list(&kwork, kwork_options, kwork_usage);
 		setup_sorting(&kwork, top_options, top_usage);
-		return perf_kwork__top(&kwork);
+		ret = perf_kwork__top(&kwork);
 	} else
 		usage_with_options(kwork_usage, kwork_options);
 
 	/* free usage string allocated by parse_options_subcommand */
 	free((void *)kwork_usage[0]);
 
-	return 0;
+	return ret;
 }
-- 
2.54.0.746.g67dd491aae-goog