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From:   Zheng Hacker <hackerzheng666@gmail.com>
Date:   Tue, 14 Mar 2023 09:59:09 +0800
Message-ID: <CAJedcCxBn=GE_pQ4xzpnvUmMA6rDuwn_AiE7S7d1EqGF9cHkNw@mail.gmail.com>
Subject: Re: [PATCH net] net: ethernet: fix use after free bug in
 ns83820_remove_one due to race condition
To:     Jakub Kicinski <kuba@kernel.org>
Cc:     Zheng Wang <zyytlz.wz@163.com>, davem@davemloft.net,
        edumazet@google.com, pabeni@redhat.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, 1395428693sheep@gmail.com,
        alex000young@gmail.com
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Jakub Kicinski <kuba@kernel.org> =E4=BA=8E2023=E5=B9=B43=E6=9C=8814=E6=97=
=A5=E5=91=A8=E4=BA=8C 07:26=E5=86=99=E9=81=93=EF=BC=9A
>
> On Thu,  9 Mar 2023 17:42:31 +0800 Zheng Wang wrote:
> > +     cancel_work_sync(&dev->tq_refill);
> >       ns83820_disable_interrupts(dev); /* paranoia */
> >
> >       unregister_netdev(ndev);
>
> Canceling the work before unregister can't work.
> Please take a closer look, the work to refill a ring should be
> canceled when the ring itself is dismantled.

Hi Jakub,

Thanks for your review! After seeing code again, I found when handling
IRQ request, it will finally call ns83820_irq->ns83820_do_isr->
ns83820_rx_kick->schedule_work to start work. So I think we should
move the code after free_irq. What do you think?

Best regards,
Zheng