On 9/5/23 11:49, Michael Walle wrote:
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 <[email protected]> Reviewed-by: Nícolas F. R. A. Prado <[email protected]> Tested-by: Nícolas F. R. A. Prado <[email protected]> Reviewed-by: AngeloGioacchino Del Regno <[email protected]>
I tried this patch as well, hit the crash during my tests. I also reviewed your changes
Tested-by: Eugen Hristev <[email protected]> Reviewed-by: Eugen Hristev <[email protected]> Eugen
--- v4: - collected tags v3: - none v2: - collected tags - fixed typos --- drivers/gpu/drm/mediatek/mtk_drm_drv.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c index 93552d76b6e7..2c582498817e 100644 --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c @@ -420,6 +420,7 @@ 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())@@ -494,7 +495,9 @@ 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");
