[PATCH v2] drm/selftests/test-drm_dp_mst_helper: Fix memory leak in sideband_msg_req_encode_decode

["José Expósito" <jose.exposito89@gmail.com>]

Avoid leaking the "out" variable if it is not possible to allocate
the "txmsg" variable.

Fixes: 09234b88ef55 ("drm/selftests/test-drm_dp_mst_helper: Move 'sideband_msg_req_encode_decode' onto the heap")
Addresses-Coverity-ID: 1475685 ("Resource leak")
Signed-off-by: José Expósito <jose.exposito89@gmail.com>

---

v2: Improve commit message
---
 drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c b/drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c
index 6b4759ed6bfd..c491429f1a02 100644
--- a/drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c
+++ b/drivers/gpu/drm/selftests/test-drm_dp_mst_helper.c
@@ -131,8 +131,10 @@ sideband_msg_req_encode_decode(struct drm_dp_sideband_msg_req_body *in)
 		return false;
 
 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
-	if (!txmsg)
+	if (!txmsg) {
+		kfree(out);
 		return false;
+	}
 
 	drm_dp_encode_sideband_req(in, txmsg);
 	ret = drm_dp_decode_sideband_req(txmsg, out);
-- 
2.25.1