linux-kernel - Re: [PATCH] net/mlx4_en: Fix an error handling path in 'mlx4_en_init

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Message-ID: <20180510141836.2qlm676j4675buti@mwanda>
Date:   Thu, 10 May 2018 17:18:36 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Yuval Shaia <yuval.shaia@...cle.com>
Cc:     Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        davem@...emloft.net, tariqt@...lanox.com, netdev@...r.kernel.org,
        linux-rdma@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] net/mlx4_en: Fix an error handling path in
 'mlx4_en_init_netdev()'

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