Re: net: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected in skb_array_produce

[Jason Wang <jasowang@redhat.com>]

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