linux-kernel - [PATCH AUTOSEL 4.4 08/31] drm/virtio: Fixes a potential NULL pointer dereference on probe failure

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Message-Id: <20210706112931.2066397-8-sashal@kernel.org>
Date:   Tue,  6 Jul 2021 07:29:08 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Xie Yongji <xieyongji@...edance.com>,
        Gerd Hoffmann <kraxel@...hat.com>,
        Sasha Levin <sashal@...nel.org>,
        dri-devel@...ts.freedesktop.org,
        virtualization@...ts.linux-foundation.org
Subject: [PATCH AUTOSEL 4.4 08/31] drm/virtio: Fixes a potential NULL pointer dereference on probe failure

From: Xie Yongji <xieyongji@...edance.com>

[ Upstream commit 17f46f488a5d82c5568e6e786cd760bba1c2ee09 ]

The dev->dev_private might not be allocated if virtio_gpu_pci_quirk()
or virtio_gpu_init() failed. In this case, we should avoid the cleanup
in virtio_gpu_release().

Signed-off-by: Xie Yongji <xieyongji@...edance.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20210517084913.403-1-xieyongji@bytedance.com
Signed-off-by: Gerd Hoffmann <kraxel@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/virtio/virtgpu_kms.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 476b9993b068..88ed5e235e55 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -257,6 +257,9 @@ int virtio_gpu_driver_unload(struct drm_device *dev)
 	flush_work(&vgdev->config_changed_work);
 	vgdev->vdev->config->del_vqs(vgdev->vdev);
 
+	if (!vgdev)
+		return;
+
 	virtio_gpu_modeset_fini(vgdev);
 	virtio_gpu_ttm_fini(vgdev);
 	virtio_gpu_free_vbufs(vgdev);
-- 
2.30.2