On Thu, 27 Jul 2023 21:48:41 +0300 Sergey Shtylyov wrote: > >> 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}()... > > >> 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... :-) Simplest fix I can think of is to take a reference on the netdev before scheduling the work, and then check if it's still registered in the work itself. Wrap the timeout work in rtnl_lock() to avoid any races there.
