Re: [PATCH] drm/virtio: Replace deprecated drm_simple_encoder_init()

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Missing error check for drm_encoder_init return value.
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commit 731688e34b570f6cb070588f1d74f9b42481123c
Author: Davide Bonatto <bonatto.davide@gmail.com>

drm/virtio: Replace deprecated drm_simple_encoder_init()

This patch replaces the deprecated drm_simple_encoder_init() with a direct
call to drm_encoder_init(), defining a default cleanup callback directly in 
virtio_gpu_encoder_funcs.

> diff --git a/drivers/gpu/drm/virtio/virtgpu_display.c b/drivers/gpu/drm/virtio/virtgpu_display.c
> index a1a875a0c706a..85986578001fe 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_display.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_display.c

[ ... ]

> @@ -306,7 +310,9 @@ static int vgdev_output_init(struct virtio_gpu_device *vgdev, int index)
>  	if (vgdev->has_edid)
>  		drm_connector_attach_edid_property(connector);
>  
> -	drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_VIRTUAL);
> +	drm_encoder_init(dev, encoder, &virtio_gpu_encoder_funcs,
> +		DRM_MODE_ENCODER_VIRTUAL, NULL);

[Severity: Medium]
Does this code need to check the return value of drm_encoder_init()?

If drm_encoder_init() fails (for example, due to a memory allocation failure 
for the encoder name), it returns a negative error code like -ENOMEM and 
cleans up the partially initialized object.

Since this return value is not validated in vgdev_output_init(), the function 
will proceed to use the uninitialized encoder, attaching it to a connector and 
registering the connector with userspace. Could this lead to a NULL pointer 
dereference or corrupted state when the DRM subsystem interacts with it?

> +
>  	drm_encoder_helper_add(encoder, &virtio_gpu_enc_helper_funcs);
>  	encoder->possible_crtcs = 1 << index;
>

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Sashiko AI review · https://sashiko.dev/#/patchset/20260909073440.52641-1-bonatto.davide@gmail.com?part=1