diff --git a/[refs] b/[refs]
index 00f407cb52e3..742566200e15 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 2c193c736803ceb547daec725e5c5d992d039f20
+refs/heads/master: 794e43b56c18b95fc9776c914a2659e7d558a352
diff --git a/trunk/tools/perf/util/session.c b/trunk/tools/perf/util/session.c
index 9401909fa283..00ab298bbb4b 100644
--- a/trunk/tools/perf/util/session.c
+++ b/trunk/tools/perf/util/session.c
@@ -696,15 +696,18 @@ static int __perf_session__process_pipe_events(struct perf_session *self,
 	p = &event;
 	p += sizeof(struct perf_event_header);
 
-	err = do_read(self->fd, p, size - sizeof(struct perf_event_header));
-	if (err <= 0) {
-		if (err == 0) {
-			pr_err("unexpected end of event stream\n");
-			goto done;
-		}
+	if (size - sizeof(struct perf_event_header)) {
+		err = do_read(self->fd, p,
+			      size - sizeof(struct perf_event_header));
+		if (err <= 0) {
+			if (err == 0) {
+				pr_err("unexpected end of event stream\n");
+				goto done;
+			}
 
-		pr_err("failed to read event data\n");
-		goto out_err;
+			pr_err("failed to read event data\n");
+			goto out_err;
+		}
 	}
 
 	if (size == 0 ||