libperf tests: Avoid uninitialized variable warning

The variable 'bf' is read (for a write call) without being initialized
triggering a memory sanitizer warning. Use 'bf' in the read and switch
the write to reading from a string.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20210114212304.4018119-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/lib/perf/tests/test-evlist.c b/tools/lib/perf/tests/test-evlist.c
index 6d8ebe0..1b225fe 100644 (file)
--- a/tools/lib/perf/tests/test-evlist.c
+++ b/tools/lib/perf/tests/test-evlist.c
@@ -208,7 +208,6 @@ static int test_mmap_thread(void)
        char path[PATH_MAX];
        int id, err, pid, go_pipe[2];
        union perf_event *event;
-       char bf;
        int count = 0;
 
        snprintf(path, PATH_MAX, "%s/kernel/debug/tracing/events/syscalls/sys_enter_prctl/id",
@@ -229,6 +228,7 @@ static int test_mmap_thread(void)
        pid = fork();
        if (!pid) {
                int i;
+               char bf;
 
                read(go_pipe[0], &bf, 1);
 
@@ -266,7 +266,7 @@ static int test_mmap_thread(void)
        perf_evlist__enable(evlist);
 
        /* kick the child and wait for it to finish */
-       write(go_pipe[1], &bf, 1);
+       write(go_pipe[1], "A", 1);
        waitpid(pid, NULL, 0);
 
        /*