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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Ian Rogers <irogers@google.com>,
        Jiri Olsa <jolsa@redhat.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Stephane Eranian <eranian@google.com>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        Anders Roxell <anders.roxell@linaro.org>
Subject: [PATCH 5.4 074/122] perf bench: Fix 2 memory sanitizer warnings
Date:   Thu, 15 Jul 2021 20:38:41 +0200
Message-Id: <20210715182509.449639236@linuxfoundation.org>
In-Reply-To: <20210715182448.393443551@linuxfoundation.org>
References: <20210715182448.393443551@linuxfoundation.org>
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From: Ian Rogers <irogers@google.com>

commit d2c73501a767514b6c85c7feff9457a165d51057 upstream.

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>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200912053725.1405857-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 tools/perf/bench/sched-messaging.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- 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_contex
 	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++) {