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

[Tariq Toukan]

On 10/05/2018 5:36 PM, Tariq Toukan wrote:
> 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.

Well, the flows in which we need to nullify the tx_rings pointer (if 
any, I still need to investigate this) is not related to this init function.

Here we're safe.

Anyway, a V2 is already submitted, please use it for your next comments. 
I think patch is OK.