From: Johan Hovold Date: Mon, 27 Aug 2018 08:21:46 +0000 (+0200) Subject: drm/mediatek: fix OF sibling-node lookup X-Git-Tag: Ubuntu-4.15.0-56.62~750 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=92575ba37bc97ff45e520f87290c20b2dff49a78;p=mirror_ubuntu-bionic-kernel.git drm/mediatek: fix OF sibling-node lookup BugLink: https://bugs.launchpad.net/bugs/1836802 commit ceff2f4dcd44abf35864d9a99f85ac619e89a01d upstream. Use the new of_get_compatible_child() helper to lookup the sibling instead of using of_find_compatible_node(), which searches the entire tree from a given start node and thus can return an unrelated (i.e. non-sibling) node. This also addresses a potential use-after-free (e.g. after probe deferral) as the tree-wide helper drops a reference to its first argument (i.e. the parent device node). While at it, also fix the related cec-node reference leak. Fixes: 8f83f26891e1 ("drm/mediatek: Add HDMI support") Cc: stable # 4.8 Cc: Junzhi Zhao Cc: Philipp Zabel Cc: CK Hu Cc: David Airlie Signed-off-by: Johan Hovold Signed-off-by: Rob Herring Signed-off-by: Greg Kroah-Hartman Signed-off-by: Andrea Righi Signed-off-by: Khalid Elmously --- diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi.c b/drivers/gpu/drm/mediatek/mtk_hdmi.c index 3ff502771ba2..f3cfdbf5ba6e 100644 --- a/drivers/gpu/drm/mediatek/mtk_hdmi.c +++ b/drivers/gpu/drm/mediatek/mtk_hdmi.c @@ -1446,8 +1446,7 @@ static int mtk_hdmi_dt_parse_pdata(struct mtk_hdmi *hdmi, } /* The CEC module handles HDMI hotplug detection */ - cec_np = of_find_compatible_node(np->parent, NULL, - "mediatek,mt8173-cec"); + cec_np = of_get_compatible_child(np->parent, "mediatek,mt8173-cec"); if (!cec_np) { dev_err(dev, "Failed to find CEC node\n"); return -EINVAL; @@ -1457,8 +1456,10 @@ static int mtk_hdmi_dt_parse_pdata(struct mtk_hdmi *hdmi, if (!cec_pdev) { dev_err(hdmi->dev, "Waiting for CEC device %pOF\n", cec_np); + of_node_put(cec_np); return -EPROBE_DEFER; } + of_node_put(cec_np); hdmi->cec_dev = &cec_pdev->dev; /*