From afe6fcb9775882230cd29b529203eabd5d2a638d Mon Sep 17 00:00:00 2001
From: Chen Ni <nichen@iscas.ac.cn>
Date: Tue, 24 Oct 2023 08:07:38 +0000
Subject: [PATCH] drm/tegra: dsi: Add missing check for of_find_device_by_node
Git-commit: afe6fcb9775882230cd29b529203eabd5d2a638d
Patch-mainline: v6.9-rc1
References: git-fixes

Add check for the return value of of_find_device_by_node() and return
the error if it fails in order to avoid NULL pointer dereference.

Fixes: e94236cde4d5 ("drm/tegra: dsi: Add ganged mode support")
Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231024080738.825553-1-nichen@iscas.ac.cn
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/tegra/dsi.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tegra/dsi.c b/drivers/gpu/drm/tegra/dsi.c
index fbfe92a816d4..e419b76e57d3 100644
--- a/drivers/gpu/drm/tegra/dsi.c
+++ b/drivers/gpu/drm/tegra/dsi.c
@@ -1544,9 +1544,11 @@ static int tegra_dsi_ganged_probe(struct tegra_dsi *dsi)
 	np = of_parse_phandle(dsi->dev->of_node, "nvidia,ganged-mode", 0);
 	if (np) {
 		struct platform_device *gangster = of_find_device_by_node(np);
+		of_node_put(np);
+		if (!gangster)
+			return -EPROBE_DEFER;
 
 		dsi->slave = platform_get_drvdata(gangster);
-		of_node_put(np);
 
 		if (!dsi->slave) {
 			put_device(&gangster->dev);
-- 
2.43.0