From: Dan Carpenter Date: Thu, 12 Sep 2024 08:44:59 +0000 (+0300) Subject: drm/mediatek: Fix potential NULL dereference in mtk_crtc_destroy() X-Git-Tag: v6.12-rc6~19^2~1^2~2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4018651ba5c409034149f297d3dd3328b91561fd;p=thirdparty%2Fkernel%2Flinux.git drm/mediatek: Fix potential NULL dereference in mtk_crtc_destroy() In mtk_crtc_create(), if the call to mbox_request_channel() fails then we set the "mtk_crtc->cmdq_client.chan" pointer to NULL. In that situation, we do not call cmdq_pkt_create(). During the cleanup, we need to check if the "mtk_crtc->cmdq_client.chan" is NULL first before calling cmdq_pkt_destroy(). Calling cmdq_pkt_destroy() is unnecessary if we didn't call cmdq_pkt_create() and it will result in a NULL pointer dereference. Fixes: 7627122fd1c0 ("drm/mediatek: Add cmdq_handle in mtk_crtc") Signed-off-by: Dan Carpenter Reviewed-by: AngeloGioacchino Del Regno Reviewed-by: CK Hu Link: https://patchwork.kernel.org/project/dri-devel/patch/cc537bd6-837f-4c85-a37b-1a007e268310@stanley.mountain/ Signed-off-by: Chun-Kuang Hu --- diff --git a/drivers/gpu/drm/mediatek/mtk_crtc.c b/drivers/gpu/drm/mediatek/mtk_crtc.c index b65f196f20154..eb0e1233ad043 100644 --- a/drivers/gpu/drm/mediatek/mtk_crtc.c +++ b/drivers/gpu/drm/mediatek/mtk_crtc.c @@ -127,9 +127,8 @@ static void mtk_crtc_destroy(struct drm_crtc *crtc) mtk_mutex_put(mtk_crtc->mutex); #if IS_REACHABLE(CONFIG_MTK_CMDQ) - cmdq_pkt_destroy(&mtk_crtc->cmdq_client, &mtk_crtc->cmdq_handle); - if (mtk_crtc->cmdq_client.chan) { + cmdq_pkt_destroy(&mtk_crtc->cmdq_client, &mtk_crtc->cmdq_handle); mbox_free_channel(mtk_crtc->cmdq_client.chan); mtk_crtc->cmdq_client.chan = NULL; }