Re: [PATCH] net/mlx4_en: Fix an error handling path in 'mlx4_en_init_netdev()'

[Tariq Toukan]

On 10/05/2018 5:18 PM, Dan Carpenter wrote:
> On Thu, May 10, 2018 at 04:38:08PM +0300, Yuval Shaia wrote:
> > On Thu, May 10, 2018 at 09:02:26AM +0200, Christophe JAILLET wrote:
> > > If an error occurs, 'mlx4_en_destroy_netdev()' is called.
> > > It then calls 'mlx4_en_free_resources()' which does the needed resources
> > > cleanup.
> > >
> > > So, doing some explicit kfree in the error handling path would lead to
> > > some double kfree.
> >
> > Patch make sense but what's bothering me is that mlx4_en_free_resources
> > loops on the entire array, assuming !priv->tx_ring[t] means entry is
> > allocated but the existing code does not assume that, see [1]. So i looked
> > to see where tx_ring array is zeroed and didn't find it.
> >
> > Am i missing something here.
>
> It's zeroed twice.  alloc_etherdev_mqs() allocates zeroed memory and
> then we do a memset(priv, 0, sizeof(struct mlx4_en_priv));
>
> regards,
> dan carpenter

We do zero (twice) on init, that's right. But I think Yuval's comment is 
valid in case of the driver went into configuration change, or down/up, 
that reallocates the rings. I'm double checking this.