Re: [PATCH V2] net/sched: Prevent notify to parent who unsupport class ops

[Jamal Hadi Salim]

On Sat, Jul 5, 2025 at 1:07 AM Cong Wang <xiyou.wangcong@xxxxxxxxx> wrote:
>
> Hi Lizhi,
>
> On Sat, Jul 05, 2025 at 09:18:22AM +0800, Lizhi Xu wrote:
> > If the parent qdisc does not support class operations then exit notify.
> >
> > In addition, the validity of the cl value is judged before executing the
> > notify. Similarly, the notify is exited when the address represented by
> > its value is invalid.
> >
> > Reported-by: syzbot+1261670bbdefc5485a06@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Closes: https://syzkaller.appspot.com/bug?extid=1261670bbdefc5485a06
>
> Maybe I didn't make it clear, I think Victor's patch also fixes this
> bug.
>
> https://lore.kernel.org/netdev/20250704163422.160424-1-victor@xxxxxxxxxxxx/
>
> Can you check if you still see the crash with his fix?
>

syzbot+1261670bbdefc5485a06@xxxxxxxxxxxxxxxxxxxxxxxxx (in this report)
is part of what Victor's patch fixes (as listed in that patch).

cheers,
jamal

> The reason why I am asking is because his fix addresses a problem
> earlier on the code path, which possibly makes your fix unnecessary.
> Hence, his fix is closer to the root cause.
>
> Please test and confirm.
>

V
> Thanks!