Re: [PATCH 5.3 134/166] net: qlogic: Fix memory leak in ql_alloc_large_buffers

Ben Hutchings
2019-11-12T19:42:52Z

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On Sun, 2019-10-06 at 19:21 +0200, Greg Kroah-Hartman wrote:
> From: Navid Emamdoost <navid.emamdoost@gmail.com>
>
> [ Upstream commit 1acb8f2a7a9f10543868ddd737e37424d5c36cf4 ]
>
> In ql_alloc_large_buffers, a new skb is allocated via netdev_alloc_skb.
> This skb should be released if pci_dma_mapping_error fails.
>
> Fixes: 0f8ab89e825f ("qla3xxx: Check return code from pci_map_single() in ql_release_to_lrg_buf_free_list(), ql_populate_free_queue(), ql_alloc_large_buffers(), and ql3xxx_send()")
> Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
> drivers/net/ethernet/qlogic/qla3xxx.c | 1 +
> 1 file changed, 1 insertion(+)
>
> --- a/drivers/net/ethernet/qlogic/qla3xxx.c
> +++ b/drivers/net/ethernet/qlogic/qla3xxx.c
> @@ -2787,6 +2787,7 @@ static int ql_alloc_large_buffers(struct
> netdev_err(qdev->ndev,
> "PCI mapping failed with error: %d\n",
> err);
> + dev_kfree_skb_irq(skb);
> ql_free_large_buffers(qdev);

So far as I can see, ql_free_large_buffers() will free the skb since
qdev->lrg_buf[i].skb already points to it. So there was no memory
leak, and this change introduced a double-free on the error path.

Am I missing something?

Ben.

> return -ENOMEM;
> }
>
>
--
Ben Hutchings
I'm not a reverse psychological virus.
Please don't copy me into your signature.

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