Re: [PATCH v3] drm/virtio: Fix handling CONFIG_DRM_VIRTIO_GPU_KMS option

From: Dmitry Osipenko
Date: Mon Mar 06 2023 - 12:45:26 EST


On 3/6/23 19:39, Dmitry Osipenko wrote:
> VirtIO-GPU got a new config option for disabling KMS. There were two
> problems left unnoticed during review when the new option was added:
>
> 1. The IS_ENABLED(CONFIG_DRM_VIRTIO_GPU_KMS) check in the code was
> inverted, hence KMS was disabled when it should be enabled and vice versa.
>
> 2. The disabled KMS crashed kernel with a NULL dereference in
> drm_kms_helper_hotplug_event(), which shall not be invoked with a
> disabled KMS.
>
> Fix the inverted config option check in the code and skip handling the
> VIRTIO_GPU_EVENT_DISPLAY sent by host when KMS is disabled in guest to fix
> the crash.
>
> Acked-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> Fixes: 72122c69d717 ("drm/virtio: Add option to disable KMS support")
> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
> ---

Added r-b from Emil and applied to misc-next

--
Best regards,
Dmitry