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

[Jason Wang]

On 2017å02æ10æ 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