Re: [PATCH net-next 2/3] bnxt_en: check for irq name truncation

[Michael Chan <michael.chan@broadcom.com>]

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On Fri, Jul 5, 2024 at 4:27 AM Simon Horman <horms@kernel.org> wrote:
> diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> index 220d05e2f6fa..15e68c8e599d 100644
> --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> @@ -10538,7 +10538,7 @@ static int bnxt_trim_rings(struct bnxt *bp, int *rx, int *tx, int max,
>         return __bnxt_trim_rings(bp, rx, tx, max, sh);
>  }
>
> -static void bnxt_setup_msix(struct bnxt *bp)
> +static int bnxt_setup_msix(struct bnxt *bp)
>  {
>         const int len = sizeof(bp->irq_tbl[0].name);
>         struct net_device *dev = bp->dev;
> @@ -10558,6 +10558,7 @@ static void bnxt_setup_msix(struct bnxt *bp)
>         for (i = 0; i < bp->cp_nr_rings; i++) {
>                 int map_idx = bnxt_cp_num_to_irq_num(bp, i);
>                 char *attr;
> +               int rc;
>
>                 if (bp->flags & BNXT_FLAG_SHARED_RINGS)
>                         attr = "TxRx";
> @@ -10566,24 +10567,35 @@ static void bnxt_setup_msix(struct bnxt *bp)
>                 else
>                         attr = "tx";
>
> -               snprintf(bp->irq_tbl[map_idx].name, len, "%s-%s-%d", dev->name,
> -                        attr, i);
> +               rc = snprintf(bp->irq_tbl[map_idx].name, len, "%s-%s-%d",
> +                             dev->name, attr, i);
> +               if (rc >= len)
> +                       return -E2BIG;

I may be missing something obvious here.  snprintf() will truncate and
not overwrite the buffer, right?  Why is it necessary to abort if
there is truncation?  Thanks.

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