[PATCH v4 3/8] drm/vc4: hdmi: Don't access the connector state in reset if kmalloc fails

[Thomas Zimmermann]

Am 07.12.20 um 14:39 schrieb Maxime Ripard:
> drm_atomic_helper_connector_reset uses kmalloc which, from an API
> standpoint, can fail, and thus setting connector->state to NULL.
> However, our reset hook then calls drm_atomic_helper_connector_tv_reset
> that will access connector->state without checking if it's a valid
> pointer or not.
> 
> Make sure we don't end up accessing a NULL pointer.
> 
> Suggested-by: Dave Stevenson <dave.stevenson at raspberrypi.com>
> Signed-off-by: Maxime Ripard <maxime at cerno.tech>

Acked-by: Thomas Zimmermann <tzimmermann at suse.de>

> ---
>   drivers/gpu/drm/vc4/vc4_hdmi.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index 5a608ed1d75e..112c09873eb4 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -171,7 +171,9 @@ static int vc4_hdmi_connector_get_modes(struct drm_connector *connector)
>   static void vc4_hdmi_connector_reset(struct drm_connector *connector)
>   {
>   	drm_atomic_helper_connector_reset(connector);
> -	drm_atomic_helper_connector_tv_reset(connector);
> +
> +	if (connector->state)
> +		drm_atomic_helper_connector_tv_reset(connector);
>   }
>   
>   static const struct drm_connector_funcs vc4_hdmi_connector_funcs = {
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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