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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Yingjie Wang <wangyingjie55@126.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 326/530] drm/radeon: Fix a missing check bug in radeon_dp_mst_detect()
Date:   Wed, 12 May 2021 16:47:16 +0200
Message-Id: <20210512144830.524382697@linuxfoundation.org>
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From: Yingjie Wang <wangyingjie55@126.com>

[ Upstream commit 25315ebfaefcffd126a266116b37bb8a3d1c4620 ]

In radeon_dp_mst_detect(), We should check whether or not @connector
has been unregistered from userspace. If the connector is unregistered,
we should return disconnected status.

Fixes: 9843ead08f18 ("drm/radeon: add DisplayPort MST support (v2)")
Signed-off-by: Yingjie Wang <wangyingjie55@126.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/radeon/radeon_dp_mst.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/radeon/radeon_dp_mst.c b/drivers/gpu/drm/radeon/radeon_dp_mst.c
index 008308780443..9bd6c0697538 100644
--- a/drivers/gpu/drm/radeon/radeon_dp_mst.c
+++ b/drivers/gpu/drm/radeon/radeon_dp_mst.c
@@ -242,6 +242,9 @@ radeon_dp_mst_detect(struct drm_connector *connector,
 		to_radeon_connector(connector);
 	struct radeon_connector *master = radeon_connector->mst_port;
 
+	if (drm_connector_is_unregistered(connector))
+		return connector_status_disconnected;
+
 	return drm_dp_mst_detect_port(connector, ctx, &master->mst_mgr,
 				      radeon_connector->port);
 }
-- 
2.30.2