[PATCH] drm/mediatek: Check GEM buffer size

[Hubert Mazur]

The buffer size is derived from parameters supplied by the userspace.
Having the size equal 0 causes allocation failure leading to kernel
panic.

Fix this by checking if size equals 0.

Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.")

Signed-off-by: Hubert Mazur <hmazur at chromium.org>
---
 drivers/gpu/drm/mediatek/mtk_drm_gem.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_gem.c b/drivers/gpu/drm/mediatek/mtk_drm_gem.c
index 9f364df52478..3b985b99d5c6 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_gem.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_gem.c
@@ -62,6 +62,11 @@ struct mtk_drm_gem_obj *mtk_drm_gem_create(struct drm_device *dev,
 	struct drm_gem_object *obj;
 	int ret;
 
+	if (size == 0) {
+		DRM_ERROR("Invalid allocation size: %zu", size);
+		return ERR_PTR(-EINVAL);
+	}
+
 	mtk_gem = mtk_drm_gem_init(dev, size);
 	if (IS_ERR(mtk_gem))
 		return ERR_CAST(mtk_gem);
-- 
2.42.0.515.g380fc7ccd1-goog