Re: [PATCH net] net: ravb: Fix possible UAF bug in ravb_remove

[Zheng Hacker]

Yunsheng Lin <linyunsheng@xxxxxxxxxx> 于2023年3月10日周五 09:12写道：
>
> On 2023/3/9 18:02, Zheng Wang wrote:
> > In ravb_probe, priv->work was bound with ravb_tx_timeout_work.
> > If timeout occurs, it will start the work. And if we call
> > ravb_remove without finishing the work, ther may be a use
>
> ther -> there
>

Sorry about the typo, will correct it in the next version.

> > after free bug on ndev.
> >
> > Fix it by finishing the job before cleanup in ravb_remove.
> >
> > Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
> > Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
> > ---
> >  drivers/net/ethernet/renesas/ravb_main.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> > index 0f54849a3823..07a08e72f440 100644
> > --- a/drivers/net/ethernet/renesas/ravb_main.c
> > +++ b/drivers/net/ethernet/renesas/ravb_main.c
> > @@ -2892,6 +2892,7 @@ static int ravb_remove(struct platform_device *pdev)
> >       struct ravb_private *priv = netdev_priv(ndev);
> >       const struct ravb_hw_info *info = priv->info;
> >
> > +     cancel_work_sync(&priv->work);
>
> As your previous patch, I still do not see anything stopping
> dev_watchdog() from calling dev->netdev_ops->ndo_tx_timeout
> after cancel_work_sync(), maybe I missed something obvious
> here?
>
Yes, that's a keyed suggestion. I was hurry to report the issue today
so wrote with many mistakes.
Thanks agagin for the advice. I will review other patch carefully.

Best regards,
Zheng

>

> >       /* Stop PTP Clock driver */
> >       if (info->ccc_gac)
> >               ravb_ptp_stop(ndev);
> >