[PATCH 4.8 29/35] drm/mediatek: fix null pointer dereference

[Greg Kroah-Hartman]

4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Matthias Brugger <matthias.bgg@xxxxxxxxx>

commit 5ad45307d990020b25a8f7486178b6e033790f70 upstream.

The probe function requests the interrupt before initializing
the ddp component. Which leads to a null pointer dereference at boot.
Fix this by requesting the interrput after all components got
initialized properly.

Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.")
Signed-off-by: Matthias Brugger <matthias.bgg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

Change-Id: I57193a7ab554dfb37c35a455900689333adf511c

---
 drivers/gpu/drm/mediatek/mtk_disp_ovl.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

--- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
@@ -249,13 +249,6 @@ static int mtk_disp_ovl_probe(struct pla
 	if (irq < 0)
 		return irq;
 
-	ret = devm_request_irq(dev, irq, mtk_disp_ovl_irq_handler,
-			       IRQF_TRIGGER_NONE, dev_name(dev), priv);
-	if (ret < 0) {
-		dev_err(dev, "Failed to request irq %d: %d\n", irq, ret);
-		return ret;
-	}
-
 	comp_id = mtk_ddp_comp_get_id(dev->of_node, MTK_DISP_OVL);
 	if (comp_id < 0) {
 		dev_err(dev, "Failed to identify by alias: %d\n", comp_id);
@@ -271,6 +264,13 @@ static int mtk_disp_ovl_probe(struct pla
 
 	platform_set_drvdata(pdev, priv);
 
+	ret = devm_request_irq(dev, irq, mtk_disp_ovl_irq_handler,
+			       IRQF_TRIGGER_NONE, dev_name(dev), priv);
+	if (ret < 0) {
+		dev_err(dev, "Failed to request irq %d: %d\n", irq, ret);
+		return ret;
+	}
+
 	ret = component_add(dev, &mtk_disp_ovl_component_ops);
 	if (ret)
 		dev_err(dev, "Failed to add component: %d\n", ret);