Possible bug?

[Usyskin, Alexander]

> On Mon, Nov 10, 2025 at 03:49:20PM +0200, Jani Nikula wrote:
> >On Sun, 09 Nov 2025, Jani Partanen <jiipee at sotapeli.fi> wrote:
> >> Hello, I just got Intel Arc B570. It seems to work fine but every boot I
> >> get this in dmesg:
> >>
> >> [  342.865944] ------------[ cut here ]------------
> >> [  342.865950] UBSAN: array-index-out-of-bounds in
> >> drivers/mtd/devices/mtd_intel_dg.c:750:15
> >> [  342.865954] index 0 is out of range for type '<unknown> [*]'
> >
> >Cc: Alexander and linux-mtd.
> >
> >It's probably due to struct intel_dg_nvm regions[] member being
> >__counted_by(nregions) but regions[] is indexed before nregions has been
> >initialized.
> 
> yeah... and we shouldn't silently continue hiding the ENOMEM... Sasha,
> something like this?
> 

In general, looks good for me, but I see that we can fill less entries because of
                if (!invm->regions[i].name)
                        continue;

Let's leave 'nvm->nregions = n;' in place, only need to fix the comment.

- - 
Thanks,
Sasha

> Lucas De Marchi
> 
> ----
> diff --git a/drivers/mtd/devices/mtd_intel_dg.c
> b/drivers/mtd/devices/mtd_intel_dg.c
> index b438ee5aacc34..114e69135b8d9 100644
> --- a/drivers/mtd/devices/mtd_intel_dg.c
> +++ b/drivers/mtd/devices/mtd_intel_dg.c
> @@ -738,6 +738,7 @@ static int intel_dg_mtd_probe(struct auxiliary_device
> *aux_dev,
> 
>   	kref_init(&nvm->refcnt);
>   	mutex_init(&nvm->lock);
> +	nvm->nregions = nregions;
> 
>   	for (n = 0, i = 0; i < INTEL_DG_NVM_REGIONS; i++) {
>   		if (!invm->regions[i].name)
> @@ -745,13 +746,15 @@ static int intel_dg_mtd_probe(struct
> auxiliary_device *aux_dev,
> 
>   		char *name = kasprintf(GFP_KERNEL, "%s.%s",
>   				       dev_name(&aux_dev->dev), invm-
> >regions[i].name);
> -		if (!name)
> -			continue;
> +		if (!name) {
> +			ret = -ENOMEM;
> +			goto err;
> +		}
> +
>   		nvm->regions[n].name = name;
>   		nvm->regions[n].id = i;
>   		n++;
>   	}
> -	nvm->nregions = n; /* in case where kasprintf fail */
> 
>   	nvm->base = devm_ioremap_resource(device, &invm->bar);
>   	if (IS_ERR(nvm->base)) {