[PATCH] drm/komeda: return early if drm_universal_plane_init() fails.

[Carsten Haitzler]

On 12/3/21 10:09, Liviu Dudau wrote:
> If drm_universal_plane_init() fails early we jump to the common cleanup code
> that calls komeda_plane_destroy() which in turn could access the uninitalised
> drm_plane and crash. Return early if an error is detected without going through
> the common code.
> 
> Reported-by: Steven Price <steven.price at arm.com>
> Signed-off-by: Liviu Dudau <liviu.dudau at arm.com>
> ---
>   drivers/gpu/drm/arm/display/komeda/komeda_plane.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_plane.c b/drivers/gpu/drm/arm/display/komeda/komeda_plane.c
> index aa193c58f4bf6d9..517b94c3bcaf966 100644
> --- a/drivers/gpu/drm/arm/display/komeda/komeda_plane.c
> +++ b/drivers/gpu/drm/arm/display/komeda/komeda_plane.c
> @@ -279,8 +279,10 @@ static int komeda_plane_add(struct komeda_kms_dev *kms,
>   
>   	komeda_put_fourcc_list(formats);
>   
> -	if (err)
> -		goto cleanup;
> +	if (err) {
> +		kfree(kplane);
> +		return err;
> +	}
>   
>   	drm_plane_helper_add(plane, &komeda_plane_helper_funcs);
>   
> 

Ummm... can I disagree here? this goto cleanup I think is just fine 
because plane has been set before drm_universal_plane_init() is called 
which is before the if (err) here. komeda_plane_destroy() in cleanup: 
does all the right things, so this patch isn't needed. I think it's less 
clean as it adds a new "handle error" path special-case instance where a 
special case is not needed. The fix to Zhou's original patch was needed 
for exactly the reason Liviu said - but not this one... ?