media: imx: Unregister csc/scaler only if registered

The csc/scaler device pointer (imxmd->m2m_vdev) is assigned
after the imx media device v4l2-async probe completes,
therefore we need to check if the device is non-NULL
before trying to unregister it.

This can be the case if the non-completed imx media device
is unbinded (or the driver is removed), leading to a kernel oops.

Fixes: a8ef0488cc59 ("media: imx: add csc/scaler mem2mem device")
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/staging/media/imx/imx-media-dev.c b/drivers/staging/media/imx/imx-media-dev.c
index 6d2205461e565d9f8e8ce63a9129ca88aed28df6..338b8bd0bb0761a0d8936d8e3a0e29d9b60e777c 100644 (file)
--- a/drivers/staging/media/imx/imx-media-dev.c
+++ b/drivers/staging/media/imx/imx-media-dev.c
@@ -53,6 +53,7 @@ static int imx6_media_probe_complete(struct v4l2_async_notifier *notifier)
        imxmd->m2m_vdev = imx_media_csc_scaler_device_init(imxmd);
        if (IS_ERR(imxmd->m2m_vdev)) {
                ret = PTR_ERR(imxmd->m2m_vdev);
+               imxmd->m2m_vdev = NULL;
                goto unlock;
        }
 
@@ -107,10 +108,14 @@ static int imx_media_remove(struct platform_device *pdev)
 
        v4l2_info(&imxmd->v4l2_dev, "Removing imx-media\n");
 
+       if (imxmd->m2m_vdev) {
+               imx_media_csc_scaler_device_unregister(imxmd->m2m_vdev);
+               imxmd->m2m_vdev = NULL;
+       }
+
        v4l2_async_notifier_unregister(&imxmd->notifier);
        imx_media_unregister_ipu_internal_subdevs(imxmd);
        v4l2_async_notifier_cleanup(&imxmd->notifier);
-       imx_media_csc_scaler_device_unregister(imxmd->m2m_vdev);
        media_device_unregister(&imxmd->md);
        v4l2_device_unregister(&imxmd->v4l2_dev);
        media_device_cleanup(&imxmd->md);