On Fri, Mar 30, 2018 at 11:44:04AM +0900, Ji-Hun Kim wrote:
> @@ -528,18 +528,22 @@ static void device_free_rings(struct vnt_private *priv)
> priv->tx0_bufs, priv->tx_bufs_dma0);
> }
>
> -static void device_init_rd0_ring(struct vnt_private *priv)
> +static int device_init_rd0_ring(struct vnt_private *priv)
> {
> int i;
> dma_addr_t curr = priv->rd0_pool_dma;
> struct vnt_rx_desc *desc;
> + int ret = 0;
Don't initialize "ret". When you do that it disables static analysis to
find uninitialized variable warnings.
>
> /* Init the RD0 ring entries */
> for (i = 0; i < priv->opts.rx_descs0;
> i ++, curr += sizeof(struct vnt_rx_desc)) {
> desc = &priv->aRD0Ring[i];
> desc->rd_info = kzalloc(sizeof(*desc->rd_info), GFP_KERNEL);
> -
> + if (!desc->rd_info) {
> + ret = -ENOMEM;
> + goto error;
> + }
> if (!device_alloc_rx_buf(priv, desc))
> dev_err(&priv->pcid->dev, "can not alloc rx bufs\n");
>
We need to handle the case where device_alloc_rx_buf() fails as well...
Some years back, I wrote a post about error handling that might be
helpful:
https://plus.google.com/106378716002406849458/posts/dnanfhQ4mHQ
You are using "one err" and "do nothing" style error handling which are
described in the post.
> @@ -550,20 +554,29 @@ static void device_init_rd0_ring(struct vnt_private
> *priv)
> if (i > 0)
> priv->aRD0Ring[i-1].next_desc = cpu_to_le32(priv->rd0_pool_dma);
> priv->pCurrRD[0] = &priv->aRD0Ring[0];
> +
> + return 0;
> +error:
> + device_free_rd0_ring(priv);
> + return ret;
> }
Of course, Jia-Ju Bai is correct to say that this is a layering
violation. Each function should only clean up after its self.
Also, this is a very typical "one err" style bug which I explain about
in my g+ post. The rule that applies here is that you should only free
things which have been allocated. Since we only partially allocated the
rd0 ring, device_free_rd0_ring() will crash when we do:
dma_unmap_single(&priv->pcid->dev, rd_info->skb_dma,
priv->rx_buf_sz, DMA_FROM_DEVICE);
"rd_info" is NULL so rd_info->skb_dma is a NULL dereference.
regards,
dan carpenter
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