From 36b617f7e4ae663fcadd202ea061ca695ca75539 Mon Sep 17 00:00:00 2001 From: Chen-Yu Tsai Date: Thu, 2 Feb 2023 12:57:34 +0800 Subject: [PATCH] drm/mediatek: dp: Only trigger DRM HPD events if bridge is attached The MediaTek DisplayPort interface bridge driver starts its interrupts as soon as its probed. However when the interrupts trigger the bridge might not have been attached to a DRM device. As drm_helper_hpd_irq_event() does not check whether the passed in drm_device is valid or not, a NULL pointer passed in results in a kernel NULL pointer dereference in it. Check whether the bridge is attached and only trigger an HPD event if it is. Fixes: f70ac097a2cf ("drm/mediatek: Add MT8195 Embedded DisplayPort driver") Signed-off-by: Chen-Yu Tsai Reviewed-by: Guillaume Ranquet Reviewed-by: AngeloGioacchino Del Regno Reviewed-by: Matthias Brugger Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20230202045734.2773503-1-wenst@chromium.org/ Signed-off-by: Chun-Kuang Hu --- drivers/gpu/drm/mediatek/mtk_dp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c index 1f94fcc144d3a..a82f53e1a1462 100644 --- a/drivers/gpu/drm/mediatek/mtk_dp.c +++ b/drivers/gpu/drm/mediatek/mtk_dp.c @@ -1823,7 +1823,8 @@ static irqreturn_t mtk_dp_hpd_event_thread(int hpd, void *dev) spin_unlock_irqrestore(&mtk_dp->irq_thread_lock, flags); if (status & MTK_DP_THREAD_CABLE_STATE_CHG) { - drm_helper_hpd_irq_event(mtk_dp->bridge.dev); + if (mtk_dp->bridge.dev) + drm_helper_hpd_irq_event(mtk_dp->bridge.dev); if (!mtk_dp->train_info.cable_plugged_in) { mtk_dp_disable_sdp_aui(mtk_dp); -- 2.30.2