From: Dan Carpenter <dan.carpenter@linaro.org>
To: oe-kbuild@lists.linux.dev, Geetha sowjanya <gakula@marvell.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: lkp@intel.com, oe-kbuild-all@lists.linux.dev, kuba@kernel.org,
davem@davemloft.net, pabeni@redhat.com, edumazet@google.com,
sgoutham@marvell.com, sbhatta@marvell.com, hkelam@marvell.com
Subject: Re: [net-next PATCH 3/9] octeontx2-pf: Create representor netdev
Date: Wed, 17 Apr 2024 18:36:47 +0300 [thread overview]
Message-ID: <d5ce5cd4-3d4f-444d-be1d-e201c1439421@moroto.mountain> (raw)
In-Reply-To: <a55c4d98-030c-420e-b29d-3836e1ce0876@moroto.mountain>
On Wed, Apr 17, 2024 at 06:24:13PM +0300, Dan Carpenter wrote:
> f9a5b510759eeb Geetha sowjanya 2024-04-16 132 int rvu_rep_create(struct otx2_nic *priv)
> f9a5b510759eeb Geetha sowjanya 2024-04-16 133 {
> f9a5b510759eeb Geetha sowjanya 2024-04-16 134 int rep_cnt = priv->rep_cnt;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 135 struct net_device *ndev;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 136 struct rep_dev *rep;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 137 int rep_id, err;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 138 u16 pcifunc;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 139
> f9a5b510759eeb Geetha sowjanya 2024-04-16 140 priv->reps = devm_kcalloc(priv->dev, rep_cnt, sizeof(struct rep_dev), GFP_KERNEL);
> f9a5b510759eeb Geetha sowjanya 2024-04-16 141 if (!priv->reps)
> f9a5b510759eeb Geetha sowjanya 2024-04-16 142 return -ENOMEM;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 143
> f9a5b510759eeb Geetha sowjanya 2024-04-16 144 for (rep_id = 0; rep_id < rep_cnt; rep_id++) {
> f9a5b510759eeb Geetha sowjanya 2024-04-16 145 ndev = alloc_etherdev(sizeof(*rep));
> f9a5b510759eeb Geetha sowjanya 2024-04-16 146 if (!ndev) {
> f9a5b510759eeb Geetha sowjanya 2024-04-16 147 dev_err(priv->dev, "PFVF representor:%d creation failed\n", rep_id);
> f9a5b510759eeb Geetha sowjanya 2024-04-16 148 err = -ENOMEM;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 149 goto exit;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 150 }
> f9a5b510759eeb Geetha sowjanya 2024-04-16 151
> f9a5b510759eeb Geetha sowjanya 2024-04-16 152 rep = netdev_priv(ndev);
> f9a5b510759eeb Geetha sowjanya 2024-04-16 153 priv->reps[rep_id] = rep;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 154 rep->mdev = priv;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 155 rep->netdev = ndev;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 156 rep->rep_id = rep_id;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 157
> f9a5b510759eeb Geetha sowjanya 2024-04-16 158 ndev->min_mtu = OTX2_MIN_MTU;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 159 ndev->max_mtu = priv->hw.max_mtu;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 160 pcifunc = priv->rep_pf_map[rep_id];
> f9a5b510759eeb Geetha sowjanya 2024-04-16 161 rep->pcifunc = pcifunc;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 162
> f9a5b510759eeb Geetha sowjanya 2024-04-16 163 snprintf(ndev->name, sizeof(ndev->name), "r%dp%dv%d", rep_id,
> f9a5b510759eeb Geetha sowjanya 2024-04-16 164 rvu_get_pf(pcifunc), (pcifunc & RVU_PFVF_FUNC_MASK));
> f9a5b510759eeb Geetha sowjanya 2024-04-16 165
> f9a5b510759eeb Geetha sowjanya 2024-04-16 166 eth_hw_addr_random(ndev);
> f9a5b510759eeb Geetha sowjanya 2024-04-16 167 if (register_netdev(ndev)) {
>
> err = register_netdev(ndev);
> if (err) {
>
> f9a5b510759eeb Geetha sowjanya 2024-04-16 168 dev_err(priv->dev, "PFVF reprentator registration failed\n");
> f9a5b510759eeb Geetha sowjanya 2024-04-16 169 free_netdev(ndev);
> ^^^^
> freed
>
> f9a5b510759eeb Geetha sowjanya 2024-04-16 @170 ndev->netdev_ops = NULL;
> ^^^^^^^^^^^^^^^^^^^^^^^
> Use after free
>
> f9a5b510759eeb Geetha sowjanya 2024-04-16 171 goto exit;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 172 }
> f9a5b510759eeb Geetha sowjanya 2024-04-16 173 }
> f9a5b510759eeb Geetha sowjanya 2024-04-16 174 err = rvu_rep_napi_init(priv);
> f9a5b510759eeb Geetha sowjanya 2024-04-16 175 if (err)
> f9a5b510759eeb Geetha sowjanya 2024-04-16 176 goto exit;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 177
> f9a5b510759eeb Geetha sowjanya 2024-04-16 178 return 0;
> f9a5b510759eeb Geetha sowjanya 2024-04-16 179 exit:
> f9a5b510759eeb Geetha sowjanya 2024-04-16 180 rvu_rep_free_netdev(priv);
>
> rvu_rep_free_netdev() also calls free_netdev() so it's a double free.
Actually the rep->netdev->netdev_ops check in rvu_rep_free_netdev() was
supposed to prevent the double free. But since rep->netdev is already
freed, then it's another use after free. You could use a different flag
instead of rep->netdev->netdev_ops to mean "don't free this". But
really, it's just better to write it how I have suggested.
My patch adds some duplicate code but when you remove the conditions in
rvu_rep_free_netdev() and the "ndev->netdev_ops = NULL" assignment, then
overall it's fewer lines of code this way.
https://staticthinking.wordpress.com/2022/04/28/free-the-last-thing-style/
regards,
dan carpenter
next prev parent reply other threads:[~2024-04-17 15:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240416050616.6056-4-gakula@marvell.com>
2024-04-17 15:24 ` [net-next PATCH 3/9] octeontx2-pf: Create representor netdev Dan Carpenter
2024-04-17 15:36 ` Dan Carpenter [this message]
2024-04-17 14:37 kernel test robot
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