netdev - Re: [PATCH net-next v3] net: sched: fix skb leak in dev_requeue

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Date:   Tue, 2 Jan 2018 13:34:12 -0800
From:   John Fastabend <john.fastabend@...il.com>
To:     David Miller <davem@...emloft.net>, weiyongjun1@...wei.com
Cc:     jhs@...atatu.com, xiyou.wangcong@...il.com, jiri@...nulli.us,
        netdev@...r.kernel.org
Subject: Re: [PATCH net-next v3] net: sched: fix skb leak in dev_requeue_skb()

On 01/02/2018 10:49 AM, David Miller wrote:
> From: Wei Yongjun <weiyongjun1@...wei.com>
> Date: Wed, 27 Dec 2017 17:05:52 +0800
> 
>> When dev_requeue_skb() is called with bluked skb list, only the
>                                         ^^^^^^
> 
> "bulked"
> 
>> first skb of the list will be requeued to qdisc layer, and leak
>> the others without free them.
>>
>> TCP is broken due to skb leak since no free skb will be considered
>> as still in the host queue and never be retransmitted. This happend
>> when dev_requeue_skb() called from qdisc_restart().
>>   qdisc_restart
>>   |-- dequeue_skb
>>   |-- sch_direct_xmit()
>>       |-- dev_requeue_skb() <-- skb may bluked
>>
>> Fix dev_requeue_skb() to requeue the full bluked list. Also change
>> to use __skb_queue_tail() in __dev_requeue_skb() to avoid skb out
>> of order.>>
>> Fixes: a53851e2c321 ("net: sched: explicit locking in gso_cpu fallback")
>> Signed-off-by: Wei Yongjun <weiyongjun1@...wei.com>
>> ---
>> v2 -> v3: move lock out of while loop
> 
> Applied, thank you.
> 

Bit late on my review but LGTM thanks!