perf test: Fix a memory leak in attr test

The get_argv_exec_path() returns a dynamic memory so it should be
freed after use.

  $ perf test -v 17
  ...
  ==141682==ERROR: LeakSanitizer: detected memory leaks

  Direct leak of 33 byte(s) in 1 object(s) allocated from:
    #0 0x7f09107d2e8f in __interceptor_malloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:145
    #1 0x7f091035f6a7 in __vasprintf_internal libio/vasprintf.c:71

  SUMMARY: AddressSanitizer: 33 byte(s) leaked in 1 allocation(s).

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20210301140409.184570-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/attr.c

@@ -182,14 +182,20 @@ int test__attr(struct test *test __maybe_unused, int subtest __maybe_unused)
 	struct stat st;
 	char path_perf[PATH_MAX];
 	char path_dir[PATH_MAX];
+	char *exec_path;
 
 	/* First try development tree tests. */
 	if (!lstat("./tests", &st))
 		return run_dir("./tests", "./perf");
 
+	exec_path = get_argv_exec_path();
+	if (exec_path == NULL)
+		return -1;
+
 	/* Then installed path. */
-	snprintf(path_dir,  PATH_MAX, "%s/tests", get_argv_exec_path());
+	snprintf(path_dir,  PATH_MAX, "%s/tests", exec_path);
 	snprintf(path_perf, PATH_MAX, "%s/perf", BINDIR);
+	free(exec_path);
 
 	if (!lstat(path_dir, &st) &&
 	    !lstat(path_perf, &st))