From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tariq Toukan Subject: Re: [PATCH] net/mlx4_en: Fix an error handling path in 'mlx4_en_init_netdev()' Date: Thu, 10 May 2018 18:03:36 +0300 Message-ID: <49d89081-95d8-e7ae-2903-372a201ff92c@mellanox.com> References: <20180510070226.19575-1-christophe.jaillet@wanadoo.fr> <20180510133808.GA10943@lap1> <20180510141836.2qlm676j4675buti@mwanda> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Dan Carpenter , Yuval Shaia Cc: Christophe JAILLET , davem@davemloft.net, netdev@vger.kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org List-Id: linux-rdma@vger.kernel.org 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.