netdev - Re: [PATCH net] net/sched: sch_taprio: fix possible use-after-free

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Date:   Wed, 18 Jan 2023 12:43:31 +0100
From:   Eric Dumazet <edumazet@...gle.com>
To:     Vinicius Costa Gomes <vinicius.gomes@...el.com>
Cc:     "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org,
        eric.dumazet@...il.com, syzbot <syzkaller@...glegroups.com>,
        Alexander Potapenko <glider@...gle.com>
Subject: Re: [PATCH net] net/sched: sch_taprio: fix possible use-after-free

On Sat, Jan 14, 2023 at 12:41 AM Vinicius Costa Gomes
<vinicius.gomes@...el.com> wrote:
>
> Hi,
>
>
> From the commit message, I got the impression that only the one
> qdisc_synchronize() in taprio_destroy() would be needed.
>

Hmm, I think you are right, qdisc_reset() is probably called while
qdisc lock is held,
with BH disabled.

So calling msleep() from qdisc_reset() is a no go.

I will send a patch removing the change in taprio_reset(), thanks.