[PATCH] drm/nouveau: Fix NULL ptr access in nv50_wndw_prepare_fb()

[Thomas Zimmermann]

Hi

I'm surprised that prepare_fb is called with fb == NULL. But, OK

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

Thanks for the fix.

Am 11.02.20 um 00:09 schrieb James Jones:
> This fixes a kernel oops when loading the nouveau
> module with fb console enabled after the change:
> 
>   drm/nouveau: Remove field nvbo from struct nouveau_framebuffer
> 
> state->fb may be NULL in nv50_wndw_prepare_fb(),
> so defer initializing nvbo from its obj[] array
> until after the NULL check.
> 
> Signed-off-by: James Jones <jajones at nvidia.com>
> ---
>  drivers/gpu/drm/nouveau/dispnv50/wndw.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/nouveau/dispnv50/wndw.c b/drivers/gpu/drm/nouveau/dispnv50/wndw.c
> index 4a67a656e007..68c0dc2dc2d3 100644
> --- a/drivers/gpu/drm/nouveau/dispnv50/wndw.c
> +++ b/drivers/gpu/drm/nouveau/dispnv50/wndw.c
> @@ -490,7 +490,7 @@ nv50_wndw_prepare_fb(struct drm_plane *plane, struct drm_plane_state *state)
>  	struct nouveau_drm *drm = nouveau_drm(plane->dev);
>  	struct nv50_wndw *wndw = nv50_wndw(plane);
>  	struct nv50_wndw_atom *asyw = nv50_wndw_atom(state);
> -	struct nouveau_bo *nvbo = nouveau_gem_object(fb->obj[0]);
> +	struct nouveau_bo *nvbo;
>  	struct nv50_head_atom *asyh;
>  	struct nv50_wndw_ctxdma *ctxdma;
>  	int ret;
> @@ -499,6 +499,7 @@ nv50_wndw_prepare_fb(struct drm_plane *plane, struct drm_plane_state *state)
>  	if (!asyw->state.fb)
>  		return 0;
>  
> +	nvbo = nouveau_gem_object(fb->obj[0]);
>  	ret = nouveau_bo_pin(nvbo, TTM_PL_FLAG_VRAM, true);
>  	if (ret)
>  		return ret;
> 

-- 
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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