Re: [PATCH] drm/vc4: Allocate the right amount of space for boot-time CRTC state.

[Daniel Vetter]

On Tue, Mar 28, 2017 at 01:13:43PM -0700, Eric Anholt wrote:
> Without this, the first modeset would dereference past the allocation
> when trying to free the mm node.
> 
> Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
> Tested-by: Stefan Wahren <stefan.wahren@xxxxxxxx>
Fixes: d8dbf44f13b9 ("drm/vc4: Make the CRTCs cooperate on allocating display lists.")
Cc: <stable@xxxxxxxxxxxxxxx> # v4.6+
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>

> ---
>  drivers/gpu/drm/vc4/vc4_crtc.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
> index 24edd0c22cc9..9d91a40e4345 100644
> --- a/drivers/gpu/drm/vc4/vc4_crtc.c
> +++ b/drivers/gpu/drm/vc4/vc4_crtc.c
> @@ -845,6 +845,17 @@ static void vc4_crtc_destroy_state(struct drm_crtc *crtc,
>  	drm_atomic_helper_crtc_destroy_state(crtc, state);
>  }
>  
> +static void
> +vc4_crtc_reset(struct drm_crtc *crtc)
> +{
> +	if (crtc->state)
> +		__drm_atomic_helper_crtc_destroy_state(crtc->state);
> +
> +	crtc->state = kzalloc(sizeof(struct vc4_crtc_state), GFP_KERNEL);
> +	if (crtc->state)
> +		crtc->state->crtc = crtc;
> +}
> +
>  static const struct drm_crtc_funcs vc4_crtc_funcs = {
>  	.set_config = drm_atomic_helper_set_config,
>  	.destroy = vc4_crtc_destroy,
> @@ -852,7 +863,7 @@ static const struct drm_crtc_funcs vc4_crtc_funcs = {
>  	.set_property = NULL,
>  	.cursor_set = NULL, /* handled by drm_mode_cursor_universal */
>  	.cursor_move = NULL, /* handled by drm_mode_cursor_universal */
> -	.reset = drm_atomic_helper_crtc_reset,
> +	.reset = vc4_crtc_reset,
>  	.atomic_duplicate_state = vc4_crtc_duplicate_state,
>  	.atomic_destroy_state = vc4_crtc_destroy_state,
>  	.gamma_set = vc4_crtc_gamma_set,
> -- 
> 2.11.0
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch