[PATCH AUTOSEL 5.1 096/141] perf test mmap-thread-lookup: Initialize variable to suppress memory sanitizer warning

From: Sasha Levin
Date: Fri Jul 19 2019 - 00:05:52 EST

From: Numfor Mbiziwo-Tiapo <nums@xxxxxxxxxx>

[ Upstream commit 4e4cf62b37da5ff45c904a3acf242ab29ed5881d ]

Running the 'perf test' command after building perf with a memory
sanitizer causes a warning that says:

WARNING: MemorySanitizer: use-of-uninitialized-value... in mmap-thread-lookup.c

Initializing the go variable to 0 silences this harmless warning.

Committer warning:

This was harmless, just a simple test writing whatever was at that
sizeof(int) memory area just to signal another thread blocked reading
that file created with pipe(). Initialize it tho so that we don't get
this warning.

Signed-off-by: Numfor Mbiziwo-Tiapo <nums@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Mark Drayton <mbd@xxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Song Liu <songliubraving@xxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20190702173716.181223-1-nums@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
tools/perf/tests/mmap-thread-lookup.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/tests/mmap-thread-lookup.c b/tools/perf/tests/mmap-thread-lookup.c
index ba87e6e8d18c..0a4301a5155c 100644
--- a/tools/perf/tests/mmap-thread-lookup.c
+++ b/tools/perf/tests/mmap-thread-lookup.c
@@ -53,7 +53,7 @@ static void *thread_fn(void *arg)
struct thread_data *td = arg;
ssize_t ret;
- int go;
+ int go = 0;

if (thread_init(td))
return NULL;