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From: Tariq Toukan <tariqt@mellanox.com>
To: Dan Carpenter <dan.carpenter@oracle.com>,
	Yuval Shaia <yuval.shaia@oracle.com>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
	davem@davemloft.net, tariqt@mellanox.com, netdev@vger.kernel.org,
	linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] net/mlx4_en: Fix an error handling path in 'mlx4_en_init_netdev()'
Date: Thu, 10 May 2018 17:36:55 +0300	[thread overview]
Message-ID: <f29e851d-c4d7-cd04-dbb7-582adebc2854@mellanox.com> (raw)
In-Reply-To: <20180510141836.2qlm676j4675buti@mwanda>



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.

  reply	other threads:[~2018-05-10 14:37 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-10  7:02 Christophe JAILLET
2018-05-10 13:38 ` Yuval Shaia
2018-05-10 14:18   ` Dan Carpenter
2018-05-10 14:36     ` Tariq Toukan [this message]
2018-05-10 15:03       ` Tariq Toukan
2018-05-10 14:35   ` Christophe JAILLET
  -- strict thread matches above, loose matches on Subject: below --
2018-05-08  9:34 Christophe JAILLET
2018-05-09 10:31 ` Tariq Toukan

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