From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jason Wang <jasowang@redhat.com>
Subject: Re: net: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected in
 skb_array_produce
Date: Fri, 10 Feb 2017 13:17:36 +0800
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Cc: Dmitry Vyukov <dvyukov@google.com>,
        David Miller <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Cong Wang <xiyou.wangcong@gmail.com>,
        netdev <netdev@vger.kernel.org>,
        syzkaller <syzkaller@googlegroups.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
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On 2017年02月10日 02:10, Michael S. Tsirkin wrote:
> On Thu, Feb 09, 2017 at 05:02:31AM -0500, Jason Wang wrote:
>> ----- Original Message -----
>>> Hello,
>>>
>>> I've got the following report while running syzkaller fuzzer on mmotm
>>> (git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git)
>>> remotes/mmotm/auto-latest ee4ba7533626ba7bf2f8b992266467ac9fdc045e:
>>>
>> [...]
>>
>>> other info that might help us debug this:
>>>
>>>   Possible interrupt unsafe locking scenario:
>>>
>>>         CPU0                    CPU1
>>>         ----                    ----
>>>    lock(&(&r->consumer_lock)->rlock);
>>>                                 local_irq_disable();
>>>                                 lock(&(&r->producer_lock)->rlock);
>>>                                 lock(&(&r->consumer_lock)->rlock);
>>>    <Interrupt>
>>>      lock(&(&r->producer_lock)->rlock);
>>>
>> Thanks a lot for the testing.
>>
>> Looks like we could address this by using skb_array_consume_bh() instead.
>>
>> Could you pls verify if the following patch works?
> I think we should use _bh for the produce call as well,
> since resizing takes the producer lock.

Looks not since irq was disabled during resizing?

Thanks