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Date: Thu, 15 Jan 2015 11:12:39 +0300 From: Dan Carpenter <dan.carpenter@...cle.com> To: Kukjin Kim <kgene@...nel.org> Cc: netdev@...r.kernel.org, Dave Miller <davem@...emloft.ne>, Byungho An <bh74.an@...sung.com> Subject: Re: [PATCH] [PATCH] net: sxgbe: Fix waring for double kfree() On Thu, Jan 15, 2015 at 10:43:11AM +0900, Kukjin Kim wrote: > rx_ring->rx_skbuff = kmalloc_array(rx_rsize, > sizeof(struct sk_buff *), GFP_KERNEL); > - if (rx_ring->rx_skbuff == NULL) > - goto rxbuff_err; > + if (!rx_ring->rx_skbuff) { This is missing a dma_free_coherent() here. > + kfree(rx_ring->rx_skbuff_dma); > + goto error; > + } > > /* initialise the buffers */ > for (desc_index = 0; desc_index < rx_rsize; desc_index++) { > @@ -502,13 +508,6 @@ static int init_rx_ring(struct net_device *dev, u8 queue_no, > err_init_rx_buffers: > while (--desc_index >= 0) > free_rx_ring(priv->device, rx_ring, desc_index); > - kfree(rx_ring->rx_skbuff); The double free bug is that free_rx_ring() frees kfree(rx_ring->rx_skbuff_dma); and kfree(rx_ring->rx_skbuff); so just calling it in a loop here will cause a double free. Also free_rx_ring() doesn't take an index parameter, it takes a size parameter. The right way to fix this is to create a release function that mirrors sxgbe_init_rx_buffers(). static void sxgbe_free_rx_buffers(struct net_device *dev, struct sxgbe_rx_norm_desc *p, int i, unsigned int dma_buf_sz, struct sxgbe_rx_queue *rx_ring) { struct sxgbe_priv_data *priv = netdev_priv(dev); kfree_skb(rx_ring->rx_skbuff[i]); dma_unmap_single(priv->device, rx_ring->rx_skbuff_dma[i], dma_buf_sz, DMA_FROM_DEVICE); } Then just swap that into the free loop instead of the free_rx_ring(). err_init_rx_buffers: while (--desc_index >= 0) { struct sxgbe_rx_norm_desc *p; p = rx_ring->dma_rx + desc_index; sxgbe_init_rx_buffers(dev, p, desc_index, bfsize, rx_ring); } kfree(rx_ring->rx_skbuff); Something like that. regards, dan carpenter -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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