Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: inconsistent lock state with usbnet/asix usb ethernet and xhci
To:     Oliver Neukum <oneukum@suse.com>,
        Eric Dumazet <eric.dumazet@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        'Linux Samsung SOC' <linux-samsung-soc@vger.kernel.org>,
        Linux USB Mailing List <linux-usb@vger.kernel.org>,
        netdev@vger.kernel.org
Cc:     Dean Jenkins <Dean_Jenkins@mentor.com>
From:   Marek Szyprowski <m.szyprowski@samsung.com>
Message-id: <02679502-cf6e-8714-e879-50a922c5d976@samsung.com>
Date:   Mon, 05 Mar 2018 08:45:00 +0100
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101
        Thunderbird/52.6.0
MIME-version: 1.0
In-reply-to: <1519747675.2649.3.camel@suse.com>
Content-type: text/plain; charset="utf-8"; format="flowed"
Content-transfer-encoding: 7bit
Content-language: en-US
CMS-TYPE: 201P
References: <CGME20180227072602eucas1p28dcdba711b3153820bd409d838cc63bd@eucas1p2.samsung.com>
        <c15c90ef-ce1b-4dd7-1d9f-673deb01b6d2@samsung.com>
        <1519740421.7296.6.camel@gmail.com>
        <bac44c1b-d701-2f6b-5e1e-738befc25c9d@samsung.com>
        <1519744167.7296.8.camel@gmail.com> <1519744400.7296.10.camel@gmail.com>
        <1519747675.2649.3.camel@suse.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi Oliver,

On 2018-02-27 17:07, Oliver Neukum wrote:
> Am Dienstag, den 27.02.2018, 07:13 -0800 schrieb Eric Dumazet:
>> On Tue, 2018-02-27 at 07:09 -0800, Eric Dumazet wrote:
>>>
>>> Note that for this one, it seems we also could perform stats updates in
>>> BH context, since skb is queued via defer_bh()
>>>
>>> But simplicity wins I guess.
>> Thinking more about this, I am not sure we have any guarantee that TX
>> and RX can not run on multiple cpus.
>>
>> Using an unique syncp is not going to be safe, even if we make lockdep
>> happy enough with the local_irq save/restore.
> Unfortunately you are right. It is not guaranteed for some hardware.

Does it mean that the fix proposed by Eric is not the proper solution?

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland