Re: [PATCH] perf bench: Fix 2 memory sanitizer warnings

From: Jiri Olsa <jolsa@redhat.com>
To: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Namhyung Kim <namhyung@kernel.org>,
	linux-kernel@vger.kernel.org,
	Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH] perf bench: Fix 2 memory sanitizer warnings
Date: Sat, 12 Sep 2020 22:51:24 +0200	[thread overview]
Message-ID: <20200912205124.GF1714160@krava> (raw)
In-Reply-To: <20200912053725.1405857-1-irogers@google.com>

On Fri, Sep 11, 2020 at 10:37:25PM -0700, Ian Rogers wrote:
> Memory sanitizer warns if a write is performed where the memory
> being read for the write is uninitialized. Avoid this warning by
> initializing the memory.
> 
> Signed-off-by: Ian Rogers <irogers@google.com>

Acked-by: Jiri Olsa <jolsa@redhat.com>

thanks,
jirka

> ---
>  tools/perf/bench/sched-messaging.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/bench/sched-messaging.c b/tools/perf/bench/sched-messaging.c
> index 71d830d7b923..cecce93ccc63 100644
> --- a/tools/perf/bench/sched-messaging.c
> +++ b/tools/perf/bench/sched-messaging.c
> @@ -66,11 +66,10 @@ static void fdpair(int fds[2])
>  /* Block until we're ready to go */
>  static void ready(int ready_out, int wakefd)
>  {
> -	char dummy;
>  	struct pollfd pollfd = { .fd = wakefd, .events = POLLIN };
>  
>  	/* Tell them we're ready. */
> -	if (write(ready_out, &dummy, 1) != 1)
> +	if (write(ready_out, "R", 1) != 1)
>  		err(EXIT_FAILURE, "CLIENT: ready write");
>  
>  	/* Wait for "GO" signal */
> @@ -85,6 +84,7 @@ static void *sender(struct sender_context *ctx)
>  	unsigned int i, j;
>  
>  	ready(ctx->ready_out, ctx->wakefd);
> +	memset(data, 'S', sizeof(data));
>  
>  	/* Now pump to every receiver. */
>  	for (i = 0; i < nr_loops; i++) {
> -- 
> 2.28.0.618.gf4bc123cb7-goog
>