From: Yunsheng Lin <linyunsheng@huawei.com>
To: David Miller <davem@davemloft.net>
Cc: <tanhuazhong@huawei.com>, <netdev@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <salil.mehta@huawei.com>,
<yisen.zhuang@huawei.com>, <linuxarm@huawei.com>,
<jakub.kicinski@netronome.com>
Subject: Re: [PATCH net 2/3] net: hns3: fix a use after free problem in hns3_nic_maybe_stop_tx()
Date: Wed, 4 Dec 2019 09:33:05 +0800 [thread overview]
Message-ID: <8901eba5-17a1-bd16-841c-3858475cfb71@huawei.com> (raw)
In-Reply-To: <20191203.115741.976811473066862969.davem@davemloft.net>
On 2019/12/4 3:57, David Miller wrote:
> From: Yunsheng Lin <linyunsheng@huawei.com>
> Date: Tue, 3 Dec 2019 12:22:11 +0800
>
>> 2. When skb_copy() returns success, the hns3_nic_maybe_stop_tx()
>> returns -EBUSY when there are not no enough space in the ring to
>> send the skb to hardware, and hns3_nic_net_xmit() will return
>> NETDEV_TX_BUSY to the upper layer, the upper layer will resend the old
>> skb later when driver wakes up the queue, but the old skb has been freed
>> by the hns3_nic_maybe_stop_tx(). Because when using the skb_copy() to
>> linearize a skb, it will return a new linearized skb, and the old skb is
>> freed, the upper layer does not have a reference to the new skb and resend
>> using the old skb, which casues a use after freed problem.
>>
>> This patch is trying to fixes the case 2.
>>
>> Maybe I should mention why hns3_nic_maybe_stop_tx() returns -EBUSY to
>> better describe the problem?
>
> I think it would help understand the code path you are fixing, yes.
Will mention that in the next version, thanks.
>
> .
>
next prev parent reply other threads:[~2019-12-04 1:33 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-03 3:08 [PATCH net 0/3] net: hns3: fixes for -net Huazhong Tan
2019-12-03 3:08 ` [PATCH net 1/3] net: hns3: fix for TX queue not restarted problem Huazhong Tan
2019-12-03 3:25 ` David Miller
2019-12-03 4:28 ` Yunsheng Lin
2019-12-03 8:48 ` David Miller
2019-12-04 1:32 ` Yunsheng Lin
2019-12-03 3:08 ` [PATCH net 2/3] net: hns3: fix a use after free problem in hns3_nic_maybe_stop_tx() Huazhong Tan
2019-12-03 3:28 ` David Miller
2019-12-03 4:22 ` Yunsheng Lin
2019-12-03 19:57 ` David Miller
2019-12-04 1:33 ` Yunsheng Lin [this message]
2019-12-03 3:08 ` [PATCH net 3/3] net: hns3: fix VF ID issue for setting VF VLAN Huazhong Tan
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