From 36aa8c61af55675ed967900fbe5deb32d776f051 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?N=C3=ADcolas=20F=2E=20R=2E=20A=2E=20Prado?= <nfraprado@collabora.com>
Date: Tue, 22 Nov 2022 09:39:49 -0500
Subject: [PATCH] drm/mediatek: Clean dangling pointer on bind error path
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Git-commit: 36aa8c61af55675ed967900fbe5deb32d776f051
Patch-mainline: v6.3-rc1
References: git-fixes

mtk_drm_bind() can fail, in which case drm_dev_put() is called,
destroying the drm_device object. However a pointer to it was still
being held in the private object, and that pointer would be passed along
to DRM in mtk_drm_sys_prepare() if a suspend were triggered at that
point, resulting in a panic. Clean the pointer when destroying the
object in the error path to prevent this from happening.

Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.")
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20221122143949.3493104-1-nfraprado@collabora.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/mediatek/mtk_drm_drv.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index 4d552c260c91..4eb696c54311 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
@@ -520,6 +520,7 @@ static int mtk_drm_bind(struct device *dev)
 err_deinit:
 	mtk_drm_kms_deinit(drm);
 err_free:
+	private->drm = NULL;
 	drm_dev_put(drm);
 	return ret;
 }
-- 
2.35.3