kmscube: check return value when creating GBM device

In the off-chance that gbm_create_device fails and returns a NULL value, further
down the line a segfault will be triggered when dereferencing gbm.dev.

Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/common.c b/common.c
index 8ad0ad5..30d6017 100644
--- a/common.c
+++ b/common.c
@@ -124,7 +124,10 @@ const struct gbm * init_gbm(int drm_fd, int w, int h, uint32_t format,
 		uint64_t modifier, bool surfaceless)
 {
 	gbm.dev = gbm_create_device(drm_fd);
-	gbm.format = format;
+	if (!gbm.dev)
+		return NULL;
+
+        gbm.format = format;
 	gbm.surface = NULL;
 
 	gbm.width = w;