Hello Sergey! > From: Sergey Shtylyov, Sent: Friday, July 28, 2023 3:49 AM > > Hello! > > On 7/27/23 11:21 AM, Paolo Abeni wrote: > [...] > >>> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c > >>> index 4d6b3b7d6abb..ce2da5101e51 100644 > >>> --- a/drivers/net/ethernet/renesas/ravb_main.c > >>> +++ b/drivers/net/ethernet/renesas/ravb_main.c > >>> @@ -2885,6 +2885,9 @@ static int ravb_remove(struct platform_device *pdev) > >>> struct ravb_private *priv = netdev_priv(ndev); > >>> const struct ravb_hw_info *info = priv->info; > >>> > >>> + netif_carrier_off(ndev); > >>> + netif_tx_disable(ndev); > >>> + cancel_work_sync(&priv->work); > >> > >> Still racy, the carrier can come back up after canceling the work. > > > > I must admit I don't see how/when this driver sets the carrier on ?!? > > The phylib code does it for this MAC driver, see the call tree of > phy_link_change(), on e.g. > https://elixir.bootlin.com/linux/v6.5-rc3/source > > >> But whatever, this is a non-issue in the first place. > > > > Do you mean the UaF can't happen? I think that is real. > > Looks possible to me, at least now... and anyway, shouldn't we clean up > after ourselves if we call schedule_work()?However my current impression is > that cancel_work_sync() should be called from ravb_close(), after calling > phy_{stop|disconnect}()... I also think so. ravb_remove() calls unregister_netdev(). -> unregister_netdev() calls rtnl_lock() and unregister_netdevice(). --> unregiter_netdevice_queue() ---> unregiter_netdevice_many() ----> unregiter_netdevice_many_notify(). -----> dev_close_many() ------> __dev_close_many() -------> ops->ndo_stop() ravb_close() calls phy_stop() -> phy_state_machine() with PHY_HALTED --> phy_link_down() ---> phy_link_change() ----> netif_carrier_off() The patch will be the following: --- drivers/net/ethernet/renesas/ravb_main.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c index 7df9f9f8e134..e452d90de7c2 100644 --- a/drivers/net/ethernet/renesas/ravb_main.c +++ b/drivers/net/ethernet/renesas/ravb_main.c @@ -2167,6 +2167,8 @@ static int ravb_close(struct net_device *ndev) of_phy_deregister_fixed_link(np); } + cancel_work_sync(&priv->work); + if (info->multi_irqs) { free_irq(priv->tx_irqs[RAVB_NC], ndev); free_irq(priv->rx_irqs[RAVB_NC], ndev); --- If this patch is acceptable, I'll submit it. But, what do you think? Best regards, Yoshihiro Shimoda > >> The fact that ravb_tx_timeout_work doesn't take any locks seems much > >> more suspicious. > > > > Indeed! But that should be a different patch, right? > > Yes. > > > Waiting a little more for feedback from renesas. > > Renesas historically hasn't shown much interest to reviewing the sh_eth/ravb > driver patches, so I took that task upon myself. I also happen to be a nominal > author of this driver... :-) > > > /P > > MBR, Sergey
