Add error handling to check NULL input in mtk_drm_crtc_dma_dev_get function.

While display path is not configured correctly, none of crtc is established. So the caller of mtk_drm_crtc_dma_dev_get may pass input parameter *crtc as NULL, Which may cause coredump when we try to get the container of NULL pointer.

Fixes: cb1d6bcca542 ("drm/mediatek: Add dma dev get function") Signed-off-by: Stuart Lee stuart.lee@mediatek.com Cc: stable@vger.kernel.org --- drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c index c277b9fae950..047c9a31d306 100644 --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c @@ -921,7 +921,14 @@ static int mtk_drm_crtc_init_comp_planes(struct drm_device *drm_dev,

struct device *mtk_drm_crtc_dma_dev_get(struct drm_crtc *crtc) { - struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc); + struct mtk_drm_crtc *mtk_crtc = NULL; + + if (!crtc) + return NULL; + + mtk_crtc = to_mtk_crtc(crtc); + if (!mtk_crtc) + return NULL;

return mtk_crtc->dma_dev; }