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

Michael S. Tsirkin
2017-02-09T18:10:56Z

On Thu, Feb 09, 2017 at 06:55:41PM +0100, Dmitry Vyukov wrote:
> On Thu, Feb 9, 2017 at 6:50 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
> > On Thu, Feb 09, 2017 at 11:49:30AM +0100, Dmitry Vyukov wrote:
> >> On Thu, Feb 9, 2017 at 11:02 AM, Jason Wang <jasowang@redhat.com> 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?
> >>
> >> No, I can't test it, sorry. This happened once on bots. And bots
> >> currently test only upstream versions.
> >
> > Which trees are tested? Will linux-next help?
>
> Linus tree, linux-next and mmotm at the moment.

OK that works, I'll add the fix to my tree includes in linux-next.

--
MST