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Subject: Re: [PATCH RESEND] net/cisco: Fix a sleep-in-atomic-context bug in
 enic_init_affinity_hint()
To:     David Miller <davem@davemloft.net>
References: <20200623.143311.995885759487352025.davem@davemloft.net>
 <20200623.152626.2206118203643133195.davem@davemloft.net>
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 <20200623.202324.442008830004872069.davem@davemloft.net>
Cc:     benve@cisco.com, _govind@gmx.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, lixuefeng@loongson.cn,
        yangtiezhu@loongson.cn
From:   Kaige Li <likaige@loongson.cn>
Message-ID: <70519029-1cfa-5fce-52f3-cfb13bf00f7d@loongson.cn>
Date:   Wed, 24 Jun 2020 11:41:14 +0800
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On 06/24/2020 11:23 AM, David Miller wrote:
> From: Kaige Li <likaige@loongson.cn>
> Date: Wed, 24 Jun 2020 09:56:47 +0800
>
>> On 06/24/2020 06:26 AM, David Miller wrote:
>>> From: David Miller <davem@davemloft.net>
>>> Date: Tue, 23 Jun 2020 14:33:11 -0700 (PDT)
>>>
>>>> Calling a NIC driver open function from a context holding a spinlock
>>>> is very much the real problem, so many operations have to sleep and
>>>> in face that ->ndo_open() method is defined as being allowed to sleep
>>>> and that's why the core networking never invokes it with spinlocks
>>>                                                         ^^^^
>>>
>>> I mean "without" of course. :-)
>>>
>>>> held.
>> Did you mean that open function should be out of spinlock? If so, I
>> will
>> send V2 patch.
> Yes, but only if that is safe.
>
> You have to analyze the locking done by this driver and fix it properly.
> I anticipate it is not just a matter of changing where the spinlock
> is held, you will have to rearchitect things a bit.

Okay, I will careful analyze this question, and make a suitable patch in V2.

Thank you.