From: Michael Walle Date: Tue, 5 Sep 2023 08:49:21 +0000 (+0200) Subject: drm/mediatek: fix kernel oops if no crtc is found X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=4662817aed5a9d6c695658d0105d8ff4b84ac6cb;p=linux.git drm/mediatek: fix kernel oops if no crtc is found drm_crtc_from_index(0) might return NULL if there are no CRTCs registered at all which will lead to a kernel oops in mtk_drm_crtc_dma_dev_get(). Add the missing return value check. Fixes: 0d9eee9118b7 ("drm/mediatek: Add drm ovl_adaptor sub driver for MT8195") Signed-off-by: Michael Walle Reviewed-by: Nícolas F. R. A. Prado Tested-by: Nícolas F. R. A. Prado Reviewed-by: AngeloGioacchino Del Regno Tested-by: Eugen Hristev Reviewed-by: Eugen Hristev Link: https://patchwork.kernel.org/project/dri-devel/patch/20230905084922.3908121-1-mwalle@kernel.org/ Signed-off-by: Chun-Kuang Hu --- diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c index 2dfaa613276a6..2b0c35cacbc6d 100644 --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c @@ -443,6 +443,7 @@ static int mtk_drm_kms_init(struct drm_device *drm) struct mtk_drm_private *private = drm->dev_private; struct mtk_drm_private *priv_n; struct device *dma_dev = NULL; + struct drm_crtc *crtc; int ret, i, j; if (drm_firmware_drivers_only()) @@ -519,7 +520,9 @@ static int mtk_drm_kms_init(struct drm_device *drm) } /* Use OVL device for all DMA memory allocations */ - dma_dev = mtk_drm_crtc_dma_dev_get(drm_crtc_from_index(drm, 0)); + crtc = drm_crtc_from_index(drm, 0); + if (crtc) + dma_dev = mtk_drm_crtc_dma_dev_get(crtc); if (!dma_dev) { ret = -ENODEV; dev_err(drm->dev, "Need at least one OVL device\n");