Messages in this thread | | | Subject | Re: [PATCH net] net: nixge: fix potential memory leak in nixge_start_xmit() | From | Zhang Changzhong <> | Date | Thu, 17 Nov 2022 11:04:23 +0800 |
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On 2022/11/17 6:36, Saeed Mahameed wrote: > On 15 Nov 21:20, Zhang Changzhong wrote: >> On 2022/11/14 18:40, Francois Romieu wrote: >>> Zhang Changzhong <zhangchangzhong@huawei.com> : >>>> The nixge_start_xmit() returns NETDEV_TX_OK but does not free skb on two >>>> error handling cases, which can lead to memory leak. >>>> >>>> To fix this, return NETDEV_TX_BUSY in case of nixge_check_tx_bd_space() >>>> fails and add dev_kfree_skb_any() in case of dma_map_single() fails. >>> >>> This patch merge two unrelated changes. Please split. >>> >>>> Fixes: 492caffa8a1a ("net: ethernet: nixge: Add support for National Instruments XGE netdev") >>>> Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com> >>>> --- >>>> drivers/net/ethernet/ni/nixge.c | 6 ++++-- >>>> 1 file changed, 4 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/net/ethernet/ni/nixge.c b/drivers/net/ethernet/ni/nixge.c >>>> index 19d043b593cc..b9091f9bbc77 100644 >>>> --- a/drivers/net/ethernet/ni/nixge.c >>>> +++ b/drivers/net/ethernet/ni/nixge.c >>>> @@ -521,13 +521,15 @@ static netdev_tx_t nixge_start_xmit(struct sk_buff *skb, >>>> if (nixge_check_tx_bd_space(priv, num_frag)) { >>>> if (!netif_queue_stopped(ndev)) >>>> netif_stop_queue(ndev); >>>> - return NETDEV_TX_OK; >>>> + return NETDEV_TX_BUSY; >>>> } >>> >>> The driver should probably check the available room before returning >>> from hard_start_xmit and turn the check above unlikely(). >>> >>> Btw there is no lock and the Tx completion is irq driven: the driver >>> is racy. :o( >>> >> >> Hi Francois, >> >> Thanks for you review. I'll make v2 according to your suggestion. >> > > you will probably need to check out: Transmit path guidelines: > https://www.kernel.org/doc/Documentation/networking/driver.rst >
Thank! This document is very helpful.
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