perf kvm: Fill in the missing session freeing after an error occurs

When an error occurs an error value is just returned without freeing the
session. So allocating and freeing session have to be matched as a pair
even if an error occurs.
Signed-off-by: NTaeung Song <treeze.taeung@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1435677525-28055-1-git-send-email-treeze.taeung@gmail.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-kvm.c

@@ -1061,8 +1061,10 @@ static int read_events(struct perf_kvm_stat *kvm)
 
 	symbol__init(&kvm->session->header.env);
 
-	if (!perf_session__has_traces(kvm->session, "kvm record"))
-		return -EINVAL;
+	if (!perf_session__has_traces(kvm->session, "kvm record")) {
+		ret = -EINVAL;
+		goto out_delete;
+	}
 
 	/*
 	 * Do not use 'isa' recorded in kvm_exit tracepoint since it is not
@@ -1070,9 +1072,13 @@ static int read_events(struct perf_kvm_stat *kvm)
 	 */
 	ret = cpu_isa_config(kvm);
 	if (ret < 0)
-		return ret;
+		goto out_delete;
 
-	return perf_session__process_events(kvm->session);
+	ret = perf_session__process_events(kvm->session);
+
+out_delete:
+	perf_session__delete(kvm->session);
+	return ret;
 }
 
 static int parse_target_str(struct perf_kvm_stat *kvm)