Re: [PATCH net] bnxt_en: don't leave an XDP program installed when the open fails

[Michael Chan]

On Mon, Sep 28, 2026 at 6:15 AM Vaibhav Nagare <nagarevaibhav@xxxxxxxxx> wrote:

> Restore the previous program when the open fails and release it only
> once the change has been committed.  The ring and feature configuration
> is left as computed for the rejected program; the device stays down on
> this path, and reconciling it is left for a separate change.
>
> Fixes: c6d30e8391b8 ("bnxt_en: Add basic XDP support.")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Vaibhav Nagare <vnagare@xxxxxxxxxx>

> @@ -435,8 +433,16 @@ static int bnxt_xdp_set(struct bnxt *bp, struct bpf_prog *prog)
>         bnxt_set_tpa_flags(bp);
>         bnxt_set_ring_params(bp);
>
> -       if (netif_running(dev))
> -               return bnxt_open_nic(bp, true, false);
> +       if (netif_running(dev)) {
> +               rc = bnxt_open_nic(bp, true, false);
> +               if (rc) {
> +                       WRITE_ONCE(bp->xdp_prog, old);
> +                       return rc;
> +               }
> +       }
> +
> +       if (old)
> +               bpf_prog_put(old);

As mentioned in your commit message, the driver's internal ring state
and the XDP program state may be out-of-sync at this point.  I think
bad things can happen if the next open succeeds.  Ideally, we want to
get everything back in sync.

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