From mboxrd@z Thu Jan  1 00:00:00 1970
From: John Fastabend <john.fastabend@gmail.com>
Subject: Re: [Patch net-next] net_sched: properly check for empty skb array on
 error path
Date: Mon, 18 Dec 2017 20:54:37 -0800
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References: <20171218223426.4685-1-xiyou.wangcong@gmail.com>
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 <4caae5f5-63e2-65c8-522e-0dfe736a7738@gmail.com>
 <CAM_iQpU8EuhBvfFtf0t0TCS-XKLffuF+E6PBM7JS8Y5dh5sR8w@mail.gmail.com>
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Cc: Linux Kernel Network Developers <netdev@vger.kernel.org>
To: Cong Wang <xiyou.wangcong@gmail.com>
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On 12/18/2017 08:31 PM, Cong Wang wrote:
> On Mon, Dec 18, 2017 at 7:58 PM, John Fastabend
> <john.fastabend@gmail.com> wrote:
>> On 12/18/2017 06:20 PM, Cong Wang wrote:
>>> On Mon, Dec 18, 2017 at 5:25 PM, John Fastabend
>>> <john.fastabend@gmail.com> wrote:
>>>> On 12/18/2017 02:34 PM, Cong Wang wrote:
>>>>> First, the check of &q->ring.queue against NULL is wrong, it
>>>>> is always false. We should check the value rather than the address.
>>>>>
>>>>
>>>> Thanks.
>>>>
>>>>> Secondly, we need the same check in pfifo_fast_reset() too,
>>>>> as both ->reset() and ->destroy() are called in qdisc_destroy().
>>>>>
>>>>
>>>> not that it hurts to have the check here, but if init fails
>>>> in qdisc_create it seems only ->destroy() is called without
>>>> a ->reset().
>>>>
>>>> Is there another path for init() to fail that I'm missing.
>>>
>>> Pretty sure ->reset() is called in qdisc_destroy() and also before
>>> ->destroy():
>>>
>>
>> Except, the failed init path does not call qdisc_destroy.
>>
>> static struct Qdisc *qdisc_create(struct net_device *dev,
>> [...]
>>
>>         if (ops->init) {
>>                 err = ops->init(sch, tca[TCA_OPTIONS]);
>>                 if (err != 0)
>>                         goto err_out5;
>>         }
>> [...]
>>
>> err_out5:
>>         /* ops->init() failed, we call ->destroy() like qdisc_create_dflt() */
>>         if (ops->destroy)
>>                 ops->destroy(sch);
> 
> Didn't I say qdisc_destroy() rather than ->destroy()? :-)
> 

Yep, thanks for the fix.

Acked-by: John Fastabend <john.fastabend@gmail.com>