Patch "media: imx: Unregister csc/scaler only if registered" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    media: imx: Unregister csc/scaler only if registered

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     media-imx-unregister-csc-scaler-only-if-registered.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 96b9592fc75efbbe7b4d6f2344a5f5d305260dce
Author: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx>
Date:   Mon Jan 4 21:34:39 2021 +0100

    media: imx: Unregister csc/scaler only if registered
    
    [ Upstream commit bb2216548a2b13cf2942a058b475438a7a6bb028 ]
    
    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@xxxxxxxxxxxxx>
    Reviewed-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
    Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
    Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/staging/media/imx/imx-media-dev.c b/drivers/staging/media/imx/imx-media-dev.c
index 2c3c2adca6832..e16408af92d9c 100644
--- 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);