From 06d1099d7f4cece7af7793ff68fabc08eb55935d Mon Sep 17 00:00:00 2001
From: Jonas Karlman <jonas@kwiboo.se>
Date: Wed, 14 Nov 2018 06:08:01 +0100
Subject: [PATCH] drm: workaround for crash when trying to open render node

---
 drivers/gpu/drm/drm_ioctl.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 34757168ffaa..0914c886277f 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -57,6 +57,9 @@ static int drm_getunique(struct drm_device *dev, void *data,
 	struct drm_unique *u = data;
 	struct drm_master *master = file_priv->master;
 
+	if (!master)
+		return -EINVAL;
+
 	if (u->unique_len >= master->unique_len) {
 		if (copy_to_user(u->unique, master->unique, master->unique_len))
 			return -EFAULT;